The issue is half medium, half technique.

First, your medium. You need something with high opacity. In wet media, we're talking black ink, and probably a wet one. Examples of Black inks which can be easily manipulated to produce an even distribution are sharpie markers, India ink, the proprietary uni-ball brand's ink pens, and Copic markers of the darkest black. For dry media, you want something soft and easily blended, with a really dark color. You want charcoal, or the softest B graphite you can find. I have found that eyeliner pens also work, as weird as that sounds. I'll talk about watercolor pencils at the very end. In either case, even the best tool is not enough. A mark which shows no hand in its production is a very difficult thing to create in traditional drawing media. My own college level instructors told me it was so difficult, it wasn't even worth chasing. (I disagree with them. Mastery of material and technique is always worth pursuing.) It is much easier in painting and printmaking techniques. Doing it with drawing media just takes practice and patience, but using the right tools for the task will make it easier. Black is always the best choice in this regard, as it is usually the most opaque pigment on any palette. The more translucent the pigment is, the harder this becomes.

The technique:

Keep in mind, this technique takes a long time to practice and master. It requires a ton of patience and endurance. It is a meditative task, in that it is slow, repetitive, boring, and more than a little uncomfortable. It is a trial of tolerance, and demanding of a quieted but focused mind. I would not do this in a place where you are likely to be distracted. Learning this technique is how I learned what it means to meditate.

1. Be gentle:
Press just hard enough to apply the pigment, and absolutely no harder. The weight of the tool alone should be more than enough. Most of an artist's hand is exposed by the damage it does to the paper. By preserving the finish of the paper, you hide your mark. Love your paper: that original finish is why you are doing this in the first place, after all!

2. Go slow:
This is especially important with inks, but just as important with dry media. Go just fast enough to leave your mark. Going too fast will pull at the texture of the paper laterally, changing the way light reflects off of it. With ink, you still need to keep a decent pace; the slower you go, the more ink soaks into the page, and the more it bleeds outward. If you're using ink, draw from where you know your bled edge will be, not where the edge of your nib is. Having a really tightly packed paper, something machine-pressed, with poor absorption, is a good thing here, as more ink will sit on the surface, making the mark take longer to dry, and getting you a darker result. For dry media, you'll want something stiff and toothy, something that can carve out your marking tool like sand paper. You won't always get to choose the best paper for the job, but if you have the choice to use the best, then you should make the choice to use the best.

3. Full length strokes:
In even, straight lines, at a constant pace, scan from one edge of the shape to the other. Do not break this line until you arrive at the opposite edge. Be careful to make the ends of each mark flush with the edges of your shape. The ends of a mark have subtle differences due to minute changes in pressure and timing as your physical hand changes direction. You want to "hide" these subtle marks by putting them in the edges of your shape. If you make the mistake of coloring a large shape in "blocks", then the mark ends line up and the series of subtle marks become a visible line of their own. If you color at random, the many marks form a texture which telegraphs your hand to the audience. So, while it is painfully slow, color it one line at a time, scanning back and forth like a computer printer. Your hand will cramp. Adjust your grip slightly with each mark to delay and reduce discomfort. If you are using dry media, you can rest your hand every few marks, but ink is far, far less forgiving.

4. Overlap:
Each mark you make, make sure you overlap the previous mark by slightly more than 50%. The thicker your mark, the easier this is to do. This is especially important with ink, as the repeated overlap ensures maximum deposition of ink at the surface, helping to hide the effects of drying time differences from one mark to the next. This is why ink is so much less forgiving. You want to finish each mark before the previous one has finished drying. The faster the ink dries, the harder this becomes without damaging the paper. Slower drying inks, like dip inks, are often preferred. This urgency imposed by the drying time for inks makes this technique rather stressful if you are not comfortable with the ink and paper yet. Reactivating inks, (like copics) which begin bleeding again when exposed to their wet medium, are a very good option, because the overlapping marks will bleed together somewhat, reducing the need of good mark timing.

5. Two coats:
Go over the work a second time, angling the strokes of the second coat by about 30°. Be even more gentle than the first pass, as you have already weakened the paper's finish. Ink will have significantly altered the absorption rate of the paper, as the dried ink will have infused its binding agent into the fibers, and your technique will need to adjust accordingly. If you are working in a gloss-finishing medium, like metal point or graphite, the smooth deposit of material is effectively a new finish for the page, and it will change how the next layer is deposited, no matter how soft your pencil is. The main purpose of this step is to get maximum color at the surface. In dry media, because you are being so gentle, you likely won't produce a very dark surface. You'll need to go over it several times, possibly many, many times if the paper is very soft or thin, depositing pigment in many thin, even layers, until the surface is completely coated, blotting out the paper fully. In ink, you always lose some color to absorption. After the initial coat, the fibers are generally clogged with dried binding agent, so the second coat is usually almost perfectly the same color as the dry pigment alone, as most of the ink will dry on the surface, rather than as a stain in the paper. In both cases, with media which blend easily, (charcoal and copics) the second layer allows loose material to blend, obscuring your mark.

Why not some other angle, like 90°? You want a slight angle for one purpose only: crushing any subtle damage your initial marks made. Provided your second coat is just as gentle, the slight angle will maximally wipe out variance from the first coat. Think of it as polishing the finish, only much more gentle. At the commonly proposed 90° angle, your second coat would create the same kind of damage as your first coat, but will intersect with the initial damage in highly concentrated points, arranged in an even pattern, forming a checkered texture. Using a slight angle spreads out the intersections, and creates a broader, less even pattern, making it much harder to see.

6. Blend it if you can: This only applies to media which can be blended and worked after application. (So, pretty much just dry media, with the special inclusion of Copic markers) Using a tortillion, makeup brush, finger, or other blending tool, gently swirl the pigment in a soft, "fluffing" gesture. This moves any loose material around, allowing you to carefully even out its distribution. (With copics, you need a 0 ink pen, that's the one containing nothing but binder and medium. Just make quick, feathery full-length strokes back and forth across the area at a slight angle to your last coat. After quite a bit of work, the marks will begin to bleed together even more. Not all reactivating inks are available in an unpigmented form- in fact, Copic is the only brand I've seen that does it.)

Dry Media: The Other Method

One of my classmates called it cottonballing. I think she just made that up herself, but it's appropriate. That's what it feels like while you're doing it: soft and fluffy. Using a soft, dark, dry material, such as charcoal, begin coloring in your shape with a very light, gentle mark. Be careful to preserve the finish. Do not lift your tool. Color the whole shape in one long, slow, gentle, ponderously meandering mark. It is, in essence, the most delicate form that scribbling can take. Make no sharp angles or straight paths, always be curving, and do not stop moving. Keep your whole shape in sight, watching for an even distribution, and take whatever arbitrary path leads you through the uneven spots most frequently. Don't watch your tool tip, allow your subconscious take care of that while you focus on the work as a whole. To quote Bob Ross, "Think like water. Let it flow." Eventually, you will have applied a thick enough layer that the surface is completely coated, and cannot possibly get any darker. As long as you avoided patterns like the plague, and preserved the paper's surface, no discernible hand will be visible. Head to an edge and feather it off, following the contour.

Watercolor Pencils

If you plan to use this tool, use appropriate paper that can stand up to localized moisture.

These tools are kind of a gray-area hybrid between watercolor painting and traditional drawing. They are pencils containing dried, brick-form watercolor paint as a lead, plus some additional ingredients to make them less brittle and a little stronger so they draw smoothly. Unfortunately, there is considerable variation in WC pencil hardness, and manufacturers have not thought to advertise their relative pencil hardness. Some brands actually have different hardness from one pencil to another depending on the pigment! Find a set with a very soft black. (Actually, in general, find a set with the softest pencils you can find; they react to water activation better, as they apply as a loose dust rather than a dense accretion.) Use one of the methods from above for dry media to color normally, as though it were just a pencil. Now get out the water and use a damp brush to carefully soak the surface. You want to activate the medium and take up as little as possible. A shorter-bristled brush with a wide surface works best here, as they have less of a belly for pigment. Work the surface until all of the paint has been evenly activated and blended while wet. Let it dry.

If this sounds like it sucks: You could always do what my teachers suggested: take up printmaking. I wasn't satisfied with that answer. Other artists have their own techniques for hiding their hand. It's something of a technical mastery "magic trick" in the arts. These techniques are mostly found among hyper-realists and photo reproduction artists. If you know any of them, or meet one, and notice that they do a good job of obliterating their hand from the finished work, ask them how they do it in a polite way. Most artists are pretty down to chat about technique- especially if you buy a commission off of them.


How can I keep my metal tools from rusting after using them with plaster?

The grit in your plaster pits the surface of your tools, especially if the plaster still contains moisture while you're carving it. And then when you clean your tools with water the water gets into the pits and if left to sit there it will eat way at the metal.

Try to get the water off your tools as fast as possible.

After cleaning your tools with water, dry throughly with a dry cloth and then blow dry the tools to get rid of all the moisture (moisture hidden below the surface residing in the pitted surface).

There are anti-rust sprays. But in your case coating the tools with a rust inhibitor would not be a good idea as the coating material could stain your plaster.

Clean and dry quickly is my recommendation.

If you store your tools in a container with a lid thrown into the container a bag of silica gel desiccant. The desiccant will help absorb any remaining moisture.


How to best attach EL wire to clothing mostly-permanantly?

The obvious solution seems like the best here. Sew it on by hand. This requires basically no sewing experience; if you can sew on a button you can do this.
Don't put the needle through the wire. Rather, put the needle through the fabric from behind, wrap it over the wire, and put it back through the fabric on the other side. This makes a loop of thread over the wire. Repeat several times in the same location until you have a sturdy loop around the wire. Tie off your thread. Repeat in another location.
Using a thicker thread will make the process faster, because you won't need as many loops in each spot. Suitable threads include: a double thickness of normal sewing thread, embroidery thread, crochet cotton, even twine if you find the appearance and texture acceptable. Remember that the knot on the inside will be thicker than the thread itself, so consider how the knot will feel when the garment is worn.
If you like, you can make the knot and the loose ends part of the design. Use a thicker yarn or string, and tie the knot on the outside. Leave the ends an inch or two, or as long as you want the fringe.
You will need to experiment to figure out the best spacing of the attachment points.


Are computer controlled sewing machine commercially available?

There are a number of computer controlled sewing machines on the market. Brother is one company, Husqvarna, and a number of other manufacturers produce devices which use software running from a computer, which typically creates a file sent to the machine. The file contains instructions to be executed with respect to movement of the mechanism which shifts the fabric (encased in an embroidery hoop) and movement of the needle and thread.
The above references consumer grade devices, possibly described as hobbyist level, although custom embroidery and sewing shops will use them for commercial use.
If you require industrial grade device related information, consider to clarify your question. I'd expect that industrial grade devices would be even more fully computer controlled.
I have a client who manufacturers quilt producing machines. Many dozens of needles with corresponding thread spools, precise fabric movement, multiple fabric layers (of course, it's a quilt) and take-up systems for the completed product. At the time I was able to view the systems, they were operating on an embedded Windows XP OS, which also contained the software to generate the stitching and related operations.


What Faber-Castell Polychromos color codes do I need to paint this?

There are a couple of ways that you can go about matching...

The first is trial and error testing on scrap paper. It's tried and true, really, because all you do is look at the color options in your set and get close, then work with additional blending with other colors to match up. Take notes. :)

The more "scientific" way is to use an application like Photoshop, The GIMP, or similar that you can use to color sample. Use the color sampler tool to get the value of the color and match it up with this chart: http://colour.granjow.net/fabercastell-polychromos.html and test the result on scrap paper.

Bear in mind that in many cases, you're likely to be layering one color over another, so the sampler may not always be accurate. Test and use your own judgement, always, before applying to your art piece. Make sure your scrap paper is the same as the paper you're using for your work.


How can I get that translucent effect on Jack O' Lanterns?

Obviously you need to remove more material in order to allow light to shine though. You know that much.

  However, whenever I try I either can't get the husk thin enough, or I go too thin and bust through.

What you need are depth checkers spaced around the surface of the lantern where you are trying to achieve this effect.

Toothpicks would be an easy suggestion for this. Put the pick in and feel the the inside of the pumpkin for where it is going to come through. You don't want the toothpick protruding the inside. That would negate its purpose as a depth check. You know it is inside enough once you barely feel it with your fingers. Putting it too far through might make it move easier which would again reduce its effectiveness. With enough toothpicks you can then use the portion that is outside of the pumpkin to gauge the thickness near the toothpick.

While I cannot find a picture of this being done to a pumpkin (yet!) a similar principal is used when making a quinzee. They use sticks to make sure the whole structure is of the same thickness.

Likely, the tactic I described above, is what was used in your first picture.   Look at where you see the pinholes of light coming though. I have used MSPaint with awesome circles to draw attention to the holes.


How to prevent acrylic or polycarbonate sheets from bending?

Consider tempered glass instead.
While using glass brings a real fear of breakage, thick glass actually doesn't break so easily, and it is quite strong. 2m x 3m is on the large size. Typical glass table tops that I remember seeing are more in the (at most) 1m x 2m size. I did a quick search and found a local (to me) vendor - local is important because picking it up yourself or getting a local truck delivery will be a lot cheaper than sending long distance - where this size is in the $1,000 range. From the same vendor, a table top 1/4 the size is ~ 1/8 the cost and 1/4" thick instead of 3/8" thick. So clearly this is a viable option, but whether it is practical or not will depend on your budget and other factors.
Glass also tends to not get scratched up as easily as most plastic, which may be a big advantage for a display medium.


Alternatives to sewing machine bobbin felt pads

Bobbin pad? Or spool pad? I use spool pads to protect the surface of my antique sewing machine (1940's Singer Featherweight). Different shaped spools can sometimes rub on the surface around the spool area. I didn't use pads when I had a modern machine.

Sometimes your thread might come on a different sized spool or a different size of hole in the middle, and a felt pad can help a spool with a larger hole sit better on the machine, and keep a constant tension instead of jumping around a lot. A friend's machine is very touchy about how it is threaded, and for shorter height spools a pad helps align the thread more with what the machine likes.

I bought my spool pads on Etsy and they are 100% wool and 5mm thick in a variety of colors. But you could likely use any felt.


From what material/s I need to create a mold so that I can pour in it safely any kind of molten plastic?

Injection molding can in fact be done at home. But judging from the OP this method would be far and above beyond the scope of his current knowledge on these types of things.

The easiest way to cast plastic parts at home or in your workspace if that’s the case would be with the use of a commercially available product such as SmoothOn.

Simple. Sold on amazon as well as most other online retailers.

I suggest doing at the very least some cursory research into the process’ used when casting/molding with SmoothOn products, as they offer a variety of materials such as polyurethanes, rubbers, silicones etc.
a quick google search will lead you in the right direction. YouTube aswell.

Also, just as a quick tip to lead you in the right direction, try finding some videos of sculptors and character designers using this stuff for they’re own casting/molding needs and you’ll have a good point of reference to start from.
Good luck :)


Making earrings and a pendant with rubies. Materials to avoid for the prong fitting

You could create a wirework bezel setting or prong setting, whichever you choose.

For the choice of metal, you could use copper wire, or copper wire which has been plated in gold or silver.  These options are available from jewellery making suppliers such as Jewellery Maker and Create & Craft


Paper brighteners used in modern papers contain fluorescent materials that make the paper glow under a black light. Bright white paper will actually glow fairly well.

Any paper that's been treated with these types of brighteners will glow under a black light. Typically, you'll see that neon colors are going to be the "brightest", and so they will glow the best.

In this case, it's not anything to do with what the material is made from, but how it's colored/treated. The chemicals are called Optical Brightening Agents, and are used in a wide variety of products to add fluorescence. Think of any neon/fluorescent paint, crayons, safety vests, etc. The OBAs work by reflecting invisible (to us) UV light as just-visible blue light, which is why they glow.


Plastic/Glass for a very large, custom frame

A clear Mylar sheet could work.

Clear, moisture resistant, acid free and archival.
And available in the size and price range you are looking for.

Here's an example available on Amazon
https://www.amazon.com/gp/aw/d/B0027A3HKG/ref=mp_s_a_1_1?ie=UTF8&qid=1473127673&sr=8-1&pi=SY200_QL40&keywords=clear+mylar+roll&dpPl=1&dpID=31N50Emps-L&ref=plSrch


How to cast beads using DIY casein plastic?

I actually did this six months ago, and the shape that I cast is still solid, virtually indestructible and mold-free, so I am speaking from experience here.

The instructions I wrote down here for
making milk paint are very similar, but with a few notable differences. It is very important that you work in a hygienic and sterile environment, which means really taking care not to introduce microorganisms and fungi.

  Casein is a milk-based product that you can make by warming whole milk
  in a copper saucepan and adding about 5 drops of lemon juice per liter. Whisk the milk vigorously, making sure to whisk the copper saucepan. You
  don’t have to get it boiling hot, but it mustn’t be cold. You will see clumps
  forming, and then remove it from the heat. Pour the entirety through a
  fine-meshed strainer and reserve the watery part (the whey).

Because ultimately we want to remove all of the water, put the clumps in a clean nylon stocking and squeeze out all of the moisture that is left. Then remove the casein and put it on a baking sheet that is lined with waxed paper / baking paper. You will find that the casein is a little crumbly and tends to fall apart, but if you squeeze it between your fingers it will retain its shape.

Then you force the casein into a beadmaking form like this and bake it at about 150 degrees Celsius for three to four hours.

NOTES

You may wonder why the copper saucepan. That is because by whisking the milk in it, you are adding copper ions to the casein, which act as a natural antibacterial and antifungal agent.

You can also add other materials like pigment or fillers to the casein - and although I haven’t tried it, I expect that using Marble Dust (available at better art supply stores) would strengthen the final product, as would adding mica flakes.


There are many versions of sunset. What colors will you be using depends on what type of sunset are you planning to paint. It is always the best to go out and observe. As always, I will be talking from my own experience.

I would advise you to look at these pages:

Munsell color system

Why is the sunset red?

You will find it very interesting. It will help you understand colors a little bit better, or should I say - the light.

As sun sets lower, thanks to atmosphere, it gets more orange, sometimes even red, and also changes the visible size. Lets say this the entire explanation (it is not) because, for more details, it would take hours to write.

Take these colors:

Prussian Blue
Cadmium Orange
Flesh color (or Raw Sienna or Naples Yellow)
White
Cadmium Red and Rouge Red
Burnt Sienna
Cadmium Yellow

Prussian Blue can be used instead of black. Take a look at the beauty of that color. Sometimes, limited palette that we have can make someone go for black color, and I understand it. Black color is nice, sure, but it will kill the vibrant color of the sunset. That is why you should use Prussian Blue!
When mixed with red, it will produce nice purple glow, and purple can be seen at sunset. I cannot explain how much I love to use this paint.

Cadmium Orange is for the strong light Sun gives us at Sunset. You need Sun to glow. After all, it is an explosion that we see. Cadmium Orange, when applied, can get you closer to that glow.

Flesh color Use it instead of white. It looks pink-ish, but it is not. If you need to make some area lighter, mix it with this color.

White - use it as a background for glowing areas. This is how it works. If there is an area you would really want to make strong in color, first paint it with white. Wait for it to dry. Paint over it with the specific color. In the picture below, I would use it for the Sun. Sometime you will not be able to produce such pure light that can be found in nature, so applying some background before painting is something you can do.

Burnt Sienna - to darken some areas that are opposite of the lit side, use this color. Example: on clouds.

Cadmium Red - is just perfection to get the glow.

Rouge Red - mixed with Prussian Blue gives deep color of the sunset sky.

Cadmium Yellow - it gives extra glow for the Sun and clouds.

Here is a color chart to help you out.

But there is a problem. This is not the only palette. Sunset can be more red, more yellow, more purple...

So, in short: for sunset go for colors that are in ranges of yellow, orange, red, purple, blue.

Lets say that sequence would be: Prussian blue/ Prussian Blue mixed with Rouge Red/ Rouge Red (not too much) / Rouge Red with Cadmium Red/ Cadmium Red (not too much)/ Cadmium Red mixed with Cadmium Orange/ Cadmium Orange mixed with Cadmium Yellow at the very end (preferably just glimpse of it at certain areas).

However...

...look at this picture above! It breaks that sequence! That is because sunset is not so uniform. But lets examine it.

The lightest part is the Sun itself. I would use white. Wait for it to dry. I would apply Cadmium Orange. But that would not be enough. I would wait for it to dry to the point where I can glaze over it with Cadmium Orange. Glazing is what you should be using here. Light scatters all around, and you need it to show. Mixing colors will not produce that effect. Glazing will.

The darkest color on that picture is not black. That is purple glazed over with Burnt Sienna and Cadmium Red. So, I would use Prussian Blue First. Mix it with some Rouge Red. That will produce fine, dark, purple color. Then, glaze over it with Burnt Sienna (but only at the darkest parts) and with Cadmium Red where dark parts of the clouds start to meet lighter clouds.

Clouds at the top are on fire. I would use Flesh Color to mix with Cadmium Red and Orange. The lightest parts seem so light and fluffy, so you need to make them thin. I would use white and glaze over it with Cadmium Yellow.

Hope this helped. It is not enough and it never will be, but it should be fine for the rough start.

Good luck.

P.S. I used these links because they were the easiest to find when typed in Google Search. My goal was not marketing of these products. You can take any brand you like, if it works for you. I, myself, am using many different brands.


How can I mount a polished stone to wood?

Epoxy resin
I love the stuff for the same reason John Vukelic's answer does so I would recommend it here as well. Even some of the cheap 2 parts should work perfectly fine for this. It is very good at bonding different material even when the surfaces are not perfectly mated.
The two parts about Gorilla Glue that need to be cautioned here is that it has expansive properties and is (as far as my experience with it goes) not a clear product once cured. These can both be mitigated with proper clamping and proper application.
Prep your surfaces
There are infinite ways I imagine that you could place your rocks so it would be hard to cover all angles of advice here but there are a couple of things I want you to look out for.

Try and mate the surface of the stones and wood as best you can. Glues will fill the gaps but if you can keep the spaces as small as possible you can help prevent air and moisture pockets which could lead to complications in the future. Again... not a huge risk but worth putting in the time.

Avoid crevasses where moisture will sit. Follow up from the last point be sure there is few places for water to sit or seep in. Depending on where your stick gets used and lives you don't want moisture build up to weaken the wood underneath. The wood is going to fail before the glue does.


How to make best out of painting poster colors on canvas?

Poster colors are water-soluble and can be reactivated. They are also relatively opaque, compared to other watercolours. But even though this type of paint might seem suitable for glazing and layering, you have to be careful when doing so, since the new colour can easily mix with the underlying one.
Like gouache and watercolours, working with poster colours on rougher types of canvas (yours is "medium grain") will cause the grain to stand out as the pigment particles will condense in the deeper parts of the texture.
I don't think there is a way to prevent this, but you can dab or smudge the surface of larger areas slightly before the paint has completely dried and settled, especially if and when you're blocking in your composition.
The trick is to work quickly and use little water.
As a side note: depending on the manufacturer (and, if one looks at translations, on country/culture) poster colours may or may not be synonymous to gouache. They are very similar, in any case, and you can use that term to find more and specific information online, if you want to.


How can I draw single hairs on a black background with charcoal or graphite?

The flocculent beauty of the work you show is not that the artists drew a single hair (that would never achieve the effect) the beauty came from the artists layering one drawn hair "over" another and repeating it until the desired depth was achieved.

I can think of two artists on Youtube who demonstrate this layering process (with explanations for their reasoning)
Darrel Tank https://www.youtube.com/watch?v=bsEiMe3OiGo
Stan Prokopenko https://www.youtube.com/watch?v=NHewz3JbKrQ

Here's a simple example of the layering process. This is based on a presentation by Darrel Tank. If you wan to see the complete process in action then check out his video series.

For this example I will use an HB mechanical pencil, a kneaded eraser and brush. Paper is 400 series strachmore (60lb). I only have white paper and black pencils. Don't focus on the materials. Focus on the process.

With a couple of simple strokes the first strands of the hair are stated.

The pencil strokes are softened using a brush by gently brushing across the surface. The harder the pencil the more difficult it will be to soften the pencil marks.

Next I take a kneaded eraser and form it into a sharp thin edge. Drawing the eraser cross the surface removes some of the pencil markings and leaves behind a negative space creating the illusion of overlapping strands of hair.

Next I go back and restate some of the lines with the pencil.

Again I use the brush to soften the marks.

The process is repeated until the desired layering effect is achieved.

Repeat the steps as many times as needed until the desired effect is achieved. Don't be as heavy handed as i was in laying down the layers. The harder you press the more difficult it will be to remove the pencil marks. A light touch is needed.

The above was just one example of how to create the layered effect you are looking to achieve. Masking and opaque paints can also be used but they too rely of the layering for the desired effect.


Your problem is the opacity of most fabric paints; most liquid ones are only designed to work effectively on a white or light-colored shirt, and the thick plasticky "puffy paint" writers aren't going to be effective over large areas or in stencils.
If you're working with just white, opaque white screen printing ink for fabric works very well. It will handle similarly to paint, and like paint you'll need to be careful about it bleeding over the edges, but it will bind to the fabric and retain its white color. Unfortunately, most other colors of screen printing ink tend to be translucent, with the expectation that they would be applied over a layer of the white ink. While aligning the two layers is fairly trivial in a professional setting, it may be more challenging with a hobbyist setup using regular stencils. As you mention just "solid bright white" in your question, however, this is likely your best bet.
Screen printing ink can be purchased in most places that sell art supplies, as well as some crafting supply stores; be sure to check that the type you are purchasing is for use on fabric (Speedball brand has distinct formulae for paper vs fabric printing, while Jacquard branded inks are formulated for both grounds; other brands may vary). Follow the instructions for setting as described on the container for your best results.


The problem with bottles
Oil paint doesn't really "dry", it hardens through a chemical reaction that turns the oil in the paint into a kind of plastic.  The oil reacts with oxygen in the air and polymerizes.
If the paint is stored in a container with no air (like a squeezable tube), it can't start the hardening process until it's dispensed and exposed to air.  If it's stored in a jar or bottle that isn't filled right to the top, the container will contain some air, and the oxygen will react with the paint.  There may not be enough air for all the paint to harden initially, but it will harden as a cumulative process.  The surface can skin over (which would need to be removed and discarded), and some of the paint below that could become partially polymerized, which will change its characteristics.
Every time you open the container, you exchange the air inside with fresh air, and more oxygen to react with the paint.  Even if you open the container only briefly to take out some paint for use, you leave the container with fresh oxygen when you reseal it, which will react with the paint while it's in storage.
A container of just linseed oil can eventually do the same thing, but it's less susceptible.  Without the paint pigment, the oil is better able to mix when you handle the container, so it has more tendency to become slightly polymerized throughout instead of the surface hardening.
Solutions
I can think of a few kinds of "adjustable" containers that would allow you to store the paint without air pockets:

Empty plastic lotion tubes designed for people who make their own cosmetics or want to repackage lotions for travel size.  They're widely available (Google "empty lotion tubes").

Large plastic syringes (no needle, just a fairly large "nozzle").  It's easy to plug the nozzle hole to seal it when not in use.  These are available on Amazon and other retailers.  They're typically made of polyethylene and can be cleaned and reused, and 100 ml is a standard size.

Small, very heavy-duty resealable plastic bags/pouches that open on the narrow end.  You can buy squeezable plastic pouches that are long zip-lock tubes designed to fill with juice and freeze to make popsicles, like these.
They also sell refillable plastic "flask" pouches with a capped nozzle designed to hold and drink beverages like this.  These tend to be bigger than your paint quantities, but you just squeeze out any air.  Or keep the empty portion flattened as you fill the pouch so all the paint is at the open end and there is no air in the unfilled portion of the pouch.

Very heavy-duty plastic bags plus an accessory resealable dispenser cap.  You can find these caps at places like Amazon or at big grocery stores in the gadget section.  They are typically a spout with a snap-close lid plus a clamp that seals the bag around the spout.  When you use up the contents, you can clean and reuse the cap.  They go by various terms, but "plastic bag spout" as a search term brought up a bunch of examples on Amazon.
You can also make your own.  Cut the top off a plastic bottle that has a cap and neck with deep, continuous threads (more likely to find on a juice bottle than a soda or water bottle).  Unscrew the cap and feed the opening of a very heavy-duty plastic bag through the bottle neck from the bottle side.  Fold it over the threads of the neck.  Then screw the cap on over the bag.
A variation is to use the top of a plastic bottle that has a flip-top cap or other closure mechanism (like a bottle from shampoo or liquid dish detergent).  The bottle should have some kind of indentation between the threaded neck and the rest of the bottle (so you can secure the bag without it pulling off).  Wrap the opening of a very heavy-duty plastic bag around the indentation and use a zip tie to make a tight seal.  Then you can use the cap's built-in dispenser.

Use a bag similar to an icing piping bag that is completely air tight (not rolled from a sheet), and that has a good sealing clip on the back and a nozzle with a sealable cap.

If you don't want to go that route and want to stick with a bottle or jar that will contain an air space, you can slow down paint hardening by displacing the air so there is no oxygen in the sealed container.  Before you recap the container, squirt in a burst of "canned air" from a duster (like "Dust-Off").  The gas is propellant and an "inert" gas.  Aim the nozzle at the wall of the container so the gas creates a vortex.  Then immediately cap the container.  This will displace most of the room air.
Another way to do this if you have access to dry ice is to drop a few very small chips of dry ice on top of the paint and lay the lid on loosely.  Give the dry ice a few minutes to sublimate and displace the air, then tighten the lid.  Use just a few small chips of dry ice so you don't freeze the paint.  They will mostly float on a layer of carbon dioxide and sublimate quickly, and it doesn't take much to produce enough carbon dioxide to fill the top of the container.


Is there a website for drop-in life drawing sessions?

@Kevin, here are the online sites my husband uses to practice figure drawing from home:

New Masters Academy
CroquisCafe on YouTube


How does one approach drawing mountains for landscape/environment concept art

I don't have any experience with Photoshop textures, so I'll limit my answer to general information.

Colors

First pick the "pure" color of the rock in bright daylight, which will be the base color of your mountain. In the first reference image of your question, that's a dark grey with a tint of brown. For other types of rock (like sandstone or marble) the base color can be a very different one.

Then adapt the color according to where the sun is situated in your picture:

The mountainside facing the sun reflects the yellow sunlight. Add more yellow or light brown to the color on this side
The mountainside opposite of the sun reflects the blue sky. Add more light or dark blue to the color on this side.
The sides perpendicular to the sun (neither facing the sun directly, nor facing away from it) should be painted in the base color.
If you want to paint a mountain at sunset, the sky is darker and the sun is red instead of yellow, so add red to the base color for the sunny side and dark blue to the shaded side.
When painting snow, the base color of snow is pale blue or grey. only the snow facing the sun is bright white.

Perspective

The common way to add perspective to a mountain range is to put a thin veil of sky color behind each mountain. That means:

The rock base color for the mountain closest to you is unchanged
For the mountain behind that, add a little light blue to the base color, then further mix this adapted base color as described above.
For the next mountain behind that, add even more blue to the base color
If the sky has a different color (like sunset), add this color to the base color instead of blue
If you want to paint a foggy / misty scene, add light grey or white to the base color (your 8th reference image with the horned spires shows this well)

Traditionally, you would start painting from the background to the foreground. When working with Photoshop, you can add a new layer, stick with the same base color and add a semi-transparent veil on top of the layer.

Bare Rock Texture

This becomes relevant at a closer perspective than the general chunky outline of a mountain. It determines how you fill in the outline with a pattern that looks natural.

Here you need to imagine how the mountain was formed during millions of years. Reference images from different places in the world may give you a feeling for how rock corrodes in different ways.

Is it a fold mountain? Then there should be regular, reoccuring lines running in parallel (as shown in the snow deposits in your first reference). These lines can be at any angle you choose and even curved (as in this reference).
Is it a fault block mountain? Then there should be high cliffs with vertical fracture lines. There can also be horizontal deposit lines in different base colors, depending on the different kinds of soil that formed the mountain.
Is it a volcanic mountain? Then the lines should all originate from a central point slightly above the top and spread out towards the base, reflecting how the volcano expelled lava and how corroding rocks and ash deposits slowly slide from the top down to the base.

Other "Stuff"

A mountain is never just a structure of bare, clean swept rocks. There are deposits of soil, snow, ash or other things accumulating on the rock surface. There are plants growing on this soil. All this adds a rounded slope to the area and another color.

You can purposefully leave this stuff out to create a more jagged, dramatic landscape or you can add more of it to give the landscape a wheathered and rounded off look.

These kinds of deposits tend to be few on the top of a mountain, filling occasional gaps at a steep angle. Towards the base they become more and filled with more material, resulting in flat angles and round outlines.


What materials can be used to stiffen a leather bag?

One thing not on your list is steel wire.

This is a sort of steel framing I suppose. But it can do a lot while remaining light and flexible. I would think you want something in spring temper, so perhaps piano wire of sufficient gauge. I suppose whenever I've seen these it's been mild steel though, somewhere around .050-.100" diameter.

"U"-shaped members on each side and each end might do the trick. They could be sewn into seams or otherwise concealed.

Interestingly, these members resist torsion (twisting) as well as bending. So, for example, if you wanted a bag that didn't flop down but was free to pull apart for access at the top (and pull together at the top to close), you could place a square wire frame at the bottom and a U or square frame on the sides only (not the ends). The frame would tend to make each side "hinge" in and out as one, roughly like the cover of a book, rather than having to pull each end separately to open.


What you are seeing may have been constructed at the gym, but they would have used a device available to anyone. It's likely called a badge laminating machine or some combination of those terms.

Amazon sells a number of designs encompassing various size capacities.

This is just one of many available. This particular model has a production restriction in that you cannot produce too many in too short of a period. If you exceed the limit, it's likely the machine will overheat and damage something internally.

More expensive models will have higher production capacity.


How can I keep my yarn relatively stationary while working?

Yarn Bowl

This is the easiest suggestion I can think of. You just need a bowl or bowl like object with a hole or path for the yarn to come out. The hole is large enough for the yarn but small enough to stop the ball from moving around. The weight of the bowl is important as well since you will be pulling on it. Having it close to yourself would help that anyway.

There are oodles of commercial options but avid crafters would make their own following the basic criteria above.


What is the difference between linen and cotton canvas?

From Understanding the difference canvas and linen:

  Canvas can mean different things to different people. In the context of painting, the word ‘canvas’ means a fabric used as a painting surface. The difference is that sometimes the canvas is made from cotton fibres and other times from linen fibres. Each material is worth looking at in more detail.

  Cotton

  Cotton is a soft, fluffy fibers that grows in a boll or protective capsule around the seeds of cotton plants. The plant is native to the Americas, Africa and India and is most often spun into yarn or thread to create a soft, breathable textile - the chances are you are wearing some cotton right now.

  The advantage of cotton to you as an artist is that it is affordable and it stretches very easily. A properly prepared cotton canvas will last a long time and is the most popular surface for oil and acrylic painting, especially for students, although it is considered too flexible for very large paintings. It is classified according to its weight and surface texture.

  When it comes to tightness, cotton comes out on top. It is possible to stretch cotton tighter than linen without straining the wooden support around the canvas, and a heavy-grade cotton can make up for its lack of strength and weight.

  Linen

  Linen is strong and durable, and remains the preferred surface for many artists but it is expensive. It is made from the fibers of the flax plant and top quality flax is harvested mainly in Western Europe. If you want your painting to last then a linen canvas is a sound investment. The threads that make up linen, known as the warp and weft threads, weigh the same, which means they are less prone to expansion or contraction due to moisture.

  Linen retains its natural oils, which helps to preserve the fibre’s flexibility and stops the canvas from going brittle. It is also regarded as having a more ‘natural’ weaved finish than cotton – a variety of textures and weights are available in both rough and smooth finishes.

  Because of its strength linen holds up to a heavy painting hand and does not become slack as easily as cotton canvas."


Is there an easy way to sharpen a wire loop carving tool?

This answer is not based on first-hand knowledge of sharpening wire loops, but is based on extrapolating what works for paint scrapers.

Many years ago while performing one of those early-marriage projects that required the removal of paint from second-hand furniture, I decided that my scraper blade needed to be replaced.  Ran over to the local hardware store and the knowledgeable clerk informed me that I did not need a new blade - just sharpen it - doh, really? how?

He proceeded to demonstrate and after thirty seconds and two swipes of a file to the cutting edge I went home.  I still have the scraper and blade, though it's much reduced in size.

I would take the same approach with these flat wire loops and use a file to restore the edge.  A few firm swipes should produce a nice edge.  It might also be possible to treat the edges the same way you would sharpen a pocket knife with a whetstone or with a small hand-held stone. It might be a bit tricky on the curved parts, but I think any artisan could handle a file to create a curved edge.


How can I finish stitching those last few inches?

You have two options: Prettier - the Ladder Stitch, and Stronger - the Baseball Stitch.

First, the Ladder Stitch.

Quoting the linked site:

  First, poke your threaded and knotted needle through the bad side of one cloth, ensuring that the knot is on the inside of the plushie. Next, pass the needle partway through the good side of the other piece of cloth at the closest location where the pieces meet. Don't pull the thread too tightly; you'll need space to perform the next step. Now that the tip of your needle is on the inside of the plushie, pass it through to the outside and pull the whole needle out. Repeat. Remember to pull the earlier stitches tight at some point, once you don't need the wiggle room.

This one, when pulled taut, closes neatly, holding the two halves pretty much flush with each other and looking very neat, but it isn't quite as strong as the latter, and when mistreated, it will just pull apart, revealing the needlework, crumpling the cloth laterally, and losing the whole appeal.

The Baseball Stitch - same as on a baseball ball, except pulled taut such that it forces the material to fold and crumple, is much stronger, but when pulled taut, the sides don't form such a neat, flush connection, but form a shallow groove, and the needlework may be visible if one peers into it.

Just push the needle from the inner side of the material onto the outer, and cross to the other side, repeating, inner to outer. When pulled taut, it crumples the material left inside into two "bars", which provide tension to the stitch preventing it from coming apart, and pressing against each other pull it inside, forming the characteristic groove. It requires much more force to break and doesn't crumple the visible surface of the cloth when strained, but if it does come apart somewhat, due to abuse, the needlework will show more, and even perfectly new it will form a deeper and more visible groove than the Ladder stitch.

Let me add that in your situation, where you're repairing items that were already subjected to abuse and likely will continue to, the baseball stitch is a better choice, as despite worse initial appearance, it doesn't degrade nearly as much when abused.


H and B relate to the hardness or softness of the pencil's graphite. "H" stands for "hard" and "B" stands for "black" with "F" right in the middle between HB and H... though, the source of the lettering seems to be debatable according to Wikipedia - H stands for "Hardtmuth" (the surname of the owner of an art supply company) and B stands for "Budweis", the town the pencil company was relocated to but "hard" and "black" are probably more useful to remember.
A "number 2 pencil" as we (in the US) are often told to use for filling out multiple choice answers on Scantron sheets, is right in the middle, the equivalent of "HB"... though, according to this site, there's no "industry standard" so one company's HB may not be the same as another's. This is also explained in the Wikipedia article linked above, which notes that on some scales, the US equivalent of HB is a #2 pencil, while other manufacturers use the equivalent HB=2½.
As a general explanation of the differences between the grades, pencils.com shows the following image:

As you can see in the image, the higher the H value, the lighter the result but the finer the point, while at the other end, the higher the B value, the darker the blackness of the graphite and wider the point.
This site has some great guidance on what the benefits of each are:

H leads are extremely smudge-resistant and give cleaner lines, making them useful for things such as outlines, technical drawings, light sketches, and even watercolors. Left-handed pencil users can also take advantage of smudge-resistant H leads. On the downside, hard leads tend to be scratchy, especially as you move up the scale.
B leads are smooth to write and draw with. They smudge easily, but are readily erased. They're perfect for pencil drawings as artists can take advantage of the brush-like expressions, especially in the higher B grades. Animators in particular enjoy using 10B over animator paper because it writes like butter, creating nice, quick, heavy lines with no friction.


What kind of paper can I use in place of U.S. currency for origami?

I don't think any such thing exists; the two closest alternatives I can think of are both long out of manufacture (Eaton's Corrasable bond, and Crane's "Old Money"). Old Money would also have been too thick, but Crane took advantage of being the manufacturer of US currency paper by creating a 100% cotton bond paper that was 30% recycled currency. (Similarly, their "Denim Blues" recycled cotton scraps they got from Levi's, and is also discontinued).

Tracing paper is thin and strong enough, but holds creases too well and makes it very difficult to reverse them cleanly. Baking parchment (which you can find in food storage sections of stores, next to the aluminum foil and plastic wrap) has a similar issue, but is a little easier to work with, and in fact one youtube video demonstrates making a flasher with it.

The best alternatives I've found for ready-made papers to fold with that are thin and strong and take a crease well and of a size to allow for more complex models are the usual hard-to-source candidates, such as thin kraft paper. The origami-shop.com website has a good (expensive) selection of the papers folders prize in sizes larger than the usual 6"x6" kami that frustrates us so.

There is, of course, the option of DIY tissue foil (i.e., laminating foil with tissue paper and spray adhesive), and sizing paper with methyl cellulose but those never appealed to me, either.

See also: What should I look for in a paper for a complex origami model?


Artificially accelerating the discolouration of leaves

The solution we used was unexpectedly simple, but not truly satisfactory:

We placed short branches with leaves in the freezer and took them out just two hours later. To my surprise, they already started to change color.

They didn’t develop the deep reds they would normally have, but had a distinctive reddish hue. I suppose repeated freezing/thawing cycles could have improved the results, but the minor that was involved in project declared them “good enough”. For a conclusive answer, further experiments need to be done next summer.


Drawing from a photograph that is too bright

The problem is that your reference photograph suffers from overexposure.
However, this image apparently contains sufficient information to tweak it to reasonable levels in Photoshop using the 'Curves' tool:

Nevertheless, I still suggest you pick a better photograph as reference: this one has a very small depth of field (i.e. the amount of spatial depth in the photo that is reasonably focused), and the level of detail on the cat's visible flank is very low (due to the high illumination of the photo and the DOF).
Here is the tweaked version of the photograph, if you insist on using it.

This question seems related to How to draw human body in chest/collarbone area?, where drawing proper shapes was problematic due to the reference image being underlit (or because the subject had insufficient lighting).


Don't use quick-crete mix your own, for one thing you don't want gravel in detailed or smooth are casting, just sand, the finer the better. I have had a lot of success using a mix of sand and marble dust but I was casting giant pacific clam shell replicas so I wanted that very white sparkly surface.
Getting it really smooth requires a sealant, concrete by itself will not be perfectly smooth just because of the sand. Using a vibrating table will help a lot with getting a smooth void free surface.
I use a pool lining mix ratio since it is a gravel free minimum void mix, something between 1:2 or 1:3(portland cement:sand) but a little experimentation is best. The water ratio is more important, you want as little water as possible, 1:3 or less, but it is effected by climate so again experimentation is best. the DIY stack has help for counter-top cement which is pretty much what you want. https://diy.stackexchange.com/questions/90389/whats-the-best-ratio-for-sand-only-concrete
I have heard good things about plasticizers but have not used them myself.


How do I determine optimal bake time for a polymer clay sculpture?

If you burn your clay your oven is too hot. So turn down the heat a bit.
You can also put your creation into a box made from aluminium foil pans. This will protect it from direct heat.

You can also bake the clay multiple times. So create the bigger pieces first, bake them, add the details and bake everything again.

Another option is to bake everything separately and put it together using glue or even the varnish for small details.


Can gold/replacement leaf be water/damp proof?

"Water-based" is not equivalent to "water soluble after drying". I have no idea what this particular (Pebeo brand) gilding size is made out of, but if it's like most others on the market, it's very similar to latex/acrylic paint (or white glue, or a number of other materials): it's water-based in that it can be thinned with water, and it can be cleaned up with plain soap and water while it's still wet. However, once it dries, it's basically insoluble: the only way to remove it is by physical means, i.e. scraping.

That said, unless a glue/paint explicitly says that it's water-resistant once dry, I wouldn't suggest using it in a wet area. It may not dissolve in water, but it may soften, or otherwise not react well.

Also, a bathroom ceiling is not where I'd personally recommend using imitation gold leaf: nevermind the glue, the leaf itself will tarnish pretty rapidly with that much moisture around. You'd need to use a sealer to prevent that, and I don't know of any that are meant to be used in damp areas on a plaster/drywall base. (Plus, how would you go about sealing the stars without getting sealer on the rest of the ceiling? Do you really want a shiny ceiling?)

If you really want to do this, I'd suggest looking into a gilding size and sealer meant to be used outdoors. That'll get you the water-resistance you need in a bathroom, but you'll hit other issues, like possibly discoloring (or worse) the rest of the ceiling, and having to use a respirator to avoid breathing noxious fumes.

One way to get around all those problems would be to get star-shaped wooden cutouts/plaques, gild those (with an outdoor-rated size and sealer), and glue them to your ceiling.


Anything better than baby oil for blending oil pastels?

Baby oil/mineral oil will never dry by evaporation like turpentine or mineral spirits ( AKA naptha , VM & P). It will not polymerize like boiled linseed oil or plain linseed oil. It may be drawn into the paper or canvas which could appear to be drying.


Why isn’t a orthographically projected plane at 45 degrees seemingly half its actual length?

For example, a vertical plane (geometrical entity) seen from the front of an orthographic system will shrink on the horizontal axis due to rotation around the vertical axis until it becomes invisible, but at middle point of rotation, the projection will be longer then half of the actual length.

How come is the projection shrinking in the first place?

Top angle rotation implies movement in 2 axis, in this case upwards and to the left. However, because from the front angle the up vector becomes backwards vector, the movement on that axis will not be visible in projection. That leaves only movement to the left to be projected, therefore the plane will shrink horizontally.

At what rate is the shrinking?

The change in size happens gradually (not linearly), first slower, then faster, or vice-versa, because the trajectory is an arc, not a straight line.

2.1. How to geometrically describe an arc/circle?

An arc can be simplified by using equal segments. Every segment has a certain angle, depending on it’s length, and the next segment inherits the angle and is rotated still by the same degree.

2.2. Why does the trajectory matters?

The closer the plane is to 90 degrees (to the projection plane) the smaller the projection, and the closer it is to being parallel, the closer to actual length. If every projected segment has a different, increasing angle, the length will grow bigger with every increment of the arc. This is the projection of the rate of shrinking..

If the trajectory would be a straight line at 45 degrees, then at 45 degrees the projection would be at half the actual length. However, this means the plane would have to shrink.

In conclusion I would like to add that this is a matter of rotation and it is valid in perspective as well. However, in perspective translation also marks the scaling of an object. I think foreshortening refers only to translation, not to rotation. Nevertheless, a projection can change size according to rotation as well.


What's the name of this type of fabric pattern?

It's called "paisley" in English.

  Paisley or paisley pattern is an ornamental design using the buta (Persian: بته) or boteh, a teardrop-shaped motif with a curved upper end. Of Persian origin,1 paisley designs became very popular in the West in the 18th and 19th centuries, following imports of post-Mughal Empire versions of the design from India, especially in the form of Kashmir shawls, and were then imitated locally. Although the fig- or almond-like form is of Persian origin, its English name derives from the town of Paisley, in West Scotland, a centre for textiles where paisley designs were produced.


Is there a way to determine the fiber content of a yarn if I've lost the label?

According to Maggie Righetti in Knitting in Plain English1, there are a couple of methods you can use to narrow down the possibilities.

The Burn Test

Take a small length of the yarn and hold a flame to one end of it. Take safety precautions when doing this. Don't perform this test near anything else that's flammable and be prepared for the yarn to burn or melt.

Animal Fibers - These will burn slightly but will not sustain a fire once the source of the flame is removed. There will also be a smell.

Plant Fibers - These will sustain a fire once lit.

Man-made - These will melt when exposed to high heat or flame.

The Rub Test

Rub a few strands of the yarn between two fingers 8 - 10 times.

Cashmere and some acrylics - These fibers will start to pill or ball when rubbed together.

The Resistance Test

Hold 3 inches of a single strand of yarn between your hands. Pull the strand firmly, then quickly release the tension.

Good wool, some acrylics - Will "stretch and snap back"

Cotton, linen, and silk - These have poor elasticity and will not snap back.

Getting Mixed Results

If you seem to get results that imply the yarn is multiple things, it probably is. Many yarns are a mixture of different fibers.

1
Righetti, M. (2007). Chapter 3: Don't Get All Balled Up About Yarn. In Knitting in Plain English. New York City, NY: St. Martin's Press.


Since you're interested in learning drawing without a specific medium, I recommend Udemy. It has a lot of great lessons, if you're willing to pay (~$15). My recommendation is https://www.udemy.com/course/the-ultimate-drawing-course-beginner-to-advanced/. Not only is the course long and comprehensive, but you can even ask the teacher questions about anything. He gives out assignments and reviews your submissions. You can see what other people submitted, too!

Note: I'm not sponsored in any way by Udemy or the course teacher. I took the course last year, and really enjoyed it.


Toilet/tissue paper is processed in such a way as to be as absorbent as possible.  So, by soaking it in water the paper fibres expand and when they dry, they shrink back and stick well to each other. Other papers, like inkjet papers, are coated, or otherwise processed, in such a way as to reduce the absorption of ink. In your case this means that if you try to make papier-mâché with such paper and just water the fibres won’t be able to absorb enough water in order to expand and stick well together when dry.

So you can use toilet/tissue paper and just water to make papier-mâché but for less absorbent paper you may need some adhesive (e.g. starch from flour).


Acrylic paint on wood: how to make it "glow" after the painting is already done

I think it's hard to judge the real difference between the paintings your nephew made and the example of the goal he has in mind: the first are taken in what seems a yellowish light, while the second is colour corrected (at least, it seems to have a proper white balance set) and taken in bright light.
Assuming both the eyes of the giraffe and the fur on the hat of the bird are white in reality, this reproduction comes closer to what the artworks look like:

The visual change this inflicts notwithstanding, there are a few remedies to make the colours in the paintings brighter (assuming no coat has been applied afterwards, since that potentially influences the solutions and makes them dependent on the nature of the coating; if this is the case, let me know, and I can update my answer):
Retouch

It's easiest to retouch or repaint (parts of) the paintings.
The saturation of the current hues may have suffered from dilution or mixing with other hues.
Use pure, unmixed paints, and apply them undiluted on top of the existing colours.
The yellow of the bird, for example, seems to be a desaturated or earthy yellow, or a yellow ochre. If a brighter hue is desired, apply an unmixed pure yellow over it.

Glazing

Alternatively, mix a (semi-)transparent colour using clear, unspoiled water and use it to give depth to the existing colours.
This technique is especially wonderful with oil paints (mixed with oil instead of water, naturally) as it gives very rich colours and depth to paintings, but with acrylics it also works quite well. You can even glaze your acrylic paintings with oil paints as well, for additional control and colour richness. For this to work the paints must have dried completely, so as not to spoil them by mixing with the existing layer.
As an example, you can use a diluted or translucent pure red (e.g. madder lake) to glaze the existing red of the Christmas hat.

Use neon colours

Use the aforementioned neon colours to really saturate some of the colours. The range of neon colours is limited, but you can use them to make some of the existing colours, like the yellow of the bird, really pop.

Other answers point out the role the support plays in the saturation of colours. Wood, especially dried, porous, and/or unprepared, may indeed absorb part of the paint or water in acrylics. Apart from their colours becoming brighter, this is another good reason to use undiluted acrylics, as they will effectively form a plastic layer on top of the support. It then functions similar to acrylic gesso, a property on which some of the solutions offered here are based.


What can I do to ensure I only erase the smaller details without affecting the area around it?

Get an erasing shield/stencil:

An erasing shield is a metal stencil that can mask off the parts of your drawing you want to protect, while exposing only the area you want to erase, so you can erase with more precision.


How can I smoothly flatten select parts of a wire design?

The flat parts of the wire are achieved by using a curved face chasing hammer and a hammering block. The chasing hammer has a slightly convex surface that makes those nice smooth transitions from the flat part of the wire to the regular rounded part of the wire. If the hammer surface is too flat you'll see hammer marks on the wire. Visually check the hammer face before buying to make sure that it is convex (slightly domed) and not fully flat or worse, concave.

Here's what one looks like:

The [my] hammering block is a smooth square of heavy steel about 4" x 4" square and quite heavy. The goal is to have a heavy and very smooth surface that's harder than the wire or metal being hammered so the surface doesn't get marked up opposite the side being hammered.

Steel wire is very hard to hammer and may be as hard or harder than the hammering block. Aluminum wire might be softer but I've heard it's brittle and might not take hammering well. Most of my experience has been with sterling silver, fine silver, brass, and copper.

The example photo is lovely but I was taught that it wasn't a good idea to hammer where wires cross as this makes weak spots in the finished piece. Maybe something has changed.


Using leather to bind books with substrate

If you are very careful with the tools you can do some shallow tooling. Tools with rounded tips would be best. You might be able to just kind of smooth out the texture of the leather in certain areas to create contrast. Even if you back the leather, deeper lines and sharper tools will cut through. You might be able to get creative with some colored leather backings so that when the tool breaks through the color underneath will show.


Inks are largely divided into two categories: dye-based and pigment-based.
Additionally, there is invisible ink, which usually consists of a variety of other ingredients that need to undergo a chemical reaction in order to become visible.
Dye is a soluble colourant, which means a dye-based ink is a solution, whereas pigments are colourants that consist of small particles, making pigment-based inks chemical suspensions (see also here).
Why the difference is important, is because both have different characteristics.
Without going into the chemical differences too much, the benefits of dye-based inks include:

Beautiful color quality
Easy to spread and paint with
Affordable and easy to find
Adheres to almost any surface

And the disadvantages are:

A tendency to fade out fast
A lack of resistance to external factors
More prone to bleeding

For pigment-based inks, the benefits are:

Resistant to most exterior factors
Can last for decades in paper
Doesn't fade out over time
Dry and adhere fast to surfaces

And the disadvantages:

Color can be a bit dull
Pretty expensive & difficult to find

Lists mostly copied verbatim from here


What are the differences between paper intended for oil painting and acrylic painting?

I am sure it's fine. It is undoubtedly primed with acrylic gesso; or rather, it is highly unlikely it was sized and primed in a traditional oil technique. In the old days, sizing (protecting the support--the painting surface--from the adverse effects of coming in contact with oils) and priming (painting the surface white for a brighter painting) were two separate steps. The canvas was stretched, sized with an animal glue, allowed to dry and then primed using thinned out (with turpentine) white pigment. If the painting was done on a board, gesso--a mixture of glue, chalk and white pigment--was used. Since the 1950's acrylic gesso has become popular. Acrylic gesso is a polymer-based liquid which sizes and primes simultaneously. It is appropriate for both oil and acrylic supports and, because it is both cheap and easy to use, is the most likely material used to prime your oil painting block.

If you like, you can paint in acrylics, let them dry, and then paint over them in oils. What you can never, ever do is paint in acrylics over oil paint.


Fast method to cut/shred glue stick into small pieces

Use a sharp knife and cut chips at one end, as if sharpening a pencil. Keep cutting until you get the needed quota :)

If a specific (different) shape of the pieces is needed, then we need more details.


How do I effectively blend with Artist's Loft colored pencils?

A common technique for pencil blending is to use either a colorless blender pencil (they make one for this brand) or to use solvents to blend, normally something like Mona Lisa odorless mineral spirits.

For blending pencils, I'm pretty sure the Artist's Loft line is wax based and so the blenders for Prismacolor should also work. The thing to remember with this technique is that you won't be able to layer more color after, so do it last.

If you try the solvent option, use it in very small amounts on a cheap, small, paint brush as you really do not need a lot. Make sure you have a few layers of pencil on first, that's how you'll get the best look. You can then layer more, when it's dry, and do more blending. It will dry very fast.

Paper also matters. Higher quality paper will allow for more pigment to be laid down and make blending easier. Some people even use 140lb hot press watercolor paper for this (check labeling to be sure), especially if they use solvent blending. You can only do so much with lower-end paper before you destroy the tooth of it or even rip through.

However, at the end of the day, these are low-end, student-grade, pencils and you're simply not going to get the same smooth blending that a professional grade pencil is going to get you.

Quick edit note: You don't need to buy high-end watercolor paper if you want to try that route. Student grade should be fine, the main difference with student to professional is the sizing and cotton content which, in this use case, isn't as important. Just make sure it is acid free (should say so on packaging).


I have a bunch of bright white cardstock. Is there something I can add to make it glossy like glossy card stock

Have you considered using a high-gloss clear spray paint?

And I would suspect that gloss = plastic to some degree, and an inkjet printer basically sets down ink droplets. If you print on glossy paper that's not specifically designed for inkjet printers, you might end up with a smear of ink. So I'd suggest do printing first, then if you use spray paint you could possibly do several pages at once.

Bonus perk of post-print gloss: inkjet ink doesn't always stay put (can be smeared by malicious fingers), so glossing the paper afterwards will help seal that ink in.

HTH


From the image of the white lamp shade i think the tabs are not interlocking, but rather interlaced and glued.
Proper interlocking would not need gluing .. for instance if the tabs where cut as trapezoids and the two edges joined by a series of folding actions to hook the wider ends into narrower inner edges of each tab.

In the other images i suspect they are also interlaced and glued, but that is not clear to me.


How can I cut a (reverse) waterdrop shape out of a cardstock perfectly?

If you have a makerspace in your area or a similar craft related activity/club, you may be able to gain use of a craft cutter such as the Silhouette Cameo or a Cricut product. Still associated with the makerspace, you may find members with a laser cutter. Stretching the application a bit means you could also use a flatbed CNC machine to make the straight and large curves, although the small point at the bottom would have to be done by hand with a sharp craft knife.

I've recently become aware of a product that can be best described as a high-frequency vibrating craft knife. At a cost of US$399, it's steep for hobby use, but might be practical for high production craft use. It's a Kickstarter campaign called Wondercutter, but as a Kickstarter item, there's a risk involved.

As I own a laser cutter which cuts cardboard quite cleanly, it's on the top of my suggestion list.


How do you fade one color to another with oil paint without getting the mixed color?

There are green areas in the photo, although they are not bold.
Maybe your solution would be not to fade but to juxtapose bold colors.

Yet, if you want to fade, painting by layers will have a cleaner mix than painting in impasto (glaze a very thin blue over the yellow). Also you could use dots of each color next to each other for a vibrant optical blending (like impressionism or pointillism).

Otherwise, first fade the colors toward grey before fading.
One of the ways to desaturate the colors is going into non complementary biases, like fade from a blue-green (cyan, phtalo, Prussian), into a blue-red (ultramarine, cobalt), fade that to a yellow-red (azo, cadmium) then a yellow-green (lemon yellow, Aureolin). The intermediary color will be greenish but muted.

Another way is to use ochres and earth tones (transitioning with a Venetian or yellow ochre, or muting the green color with green-earth or another greenish brown paint), and yet another way is to use opposite colors to mute the intermediary color (i.e. mute the green with a glaze of red).

However, I think the best way to achieve a clean contrast with high colors is to mix as little as possible.


How to attach PVC piping to a flat surface

I would suggest Plasticweld epoxy putty. It's designed to work with most plastics, including PVC.

Because it's a putty, it's moldable and can be used to attach to a greater amount of surface area of the pipe to the gun.

You'll be most successful by sanding the portion of the pipe and gun where you plan to use the adhesive, giving the putty a better sticking area. I would also wipe clean with some rubbing alcohol to remove  dust particles (alcohol because it dries quickly).

In the end, the putty will be flat against the gun surface, but U-shaped against the pipe.

The putty can also be sanded, drilled, painted, etc. once dry.


Blackening steel with oil vs. vinegar - and others?

Treating with vinegar (or other acids) tends to form a dark grey patina, depending on how it is applied it can also also show variations in shade. More viscous things like mustard and tomato sauce can be dabbled or stippled on to create a distinctly mottled effect. Acids also work well to strip off or at least dull bright zing plating and galvanising.

This finish needs to be dried and sealed with wax, oil, lacquer etc fairly quickly (ie within minutes) or it will start to rust. Also because it is somewhat porous it can be a good base for tinted oils and waxes.

Oil blacking works by polymerising and partly burning the oil. Here the temperature is quite important as the metal needs to be hot enough to blacken the oil without burning it off completely. If you watch the oxide colours as it heats up the point when it goes from deep blue to grey is usually about right. This process is pretty similar to seasoning a cast iron pan. You can either dip the piece in a container of oil or paint it on with a rag (don't use a synthetic brush, it will just melt).

Oil blacking is reasonably stable and doesn't require any additional sealing, although a layer of hard wax, reapplied every so often will make it a bit more durable.

I would recommend using linseed oil or similar rather than motor oil as motor oil (especially used) will contain all sorts of additives that you don't really want to be handling or inhaling. I've found that a mixture of linseed oil and paraffin wax works well.

Another option is to allow the piece to rust and then treat it with a rust converter such as Fertan, these are generally phosphoric and/or tannic acid based and will turn the rust a deep blue/black which can then be sealed with wax, oil etc


It's a woven rib twill (diagonal pattern) like denim except that in denim the twill pattern is tighter and smaller in scale and the blue yarns in the rib cover the white yarns.  In this fabric the brown and the tan yarns both show.

Chinos (khakis) are also a woven twill, although tighter and not as bold as this twill, and both yarns are usually the same pale tan color.

Fun fact: the reason jeans look whiter over time at high-wear points like knees and hems and the edges of pockets is that as the blue yarns are rubbed away with wear and tear, the white yarns underneath begin to show through.

Probably the best way to describe this fabric when looking for another pair is that it's a heavy twill in which there are two colors in the diagonal.  Best yet is to take these with you if you shop in physical stores.

Good luck, this is a nice fabric.


Can boiled linseed oil from hardware stores be used for oil painting applications or cleaning brushes?

Since you tagged this as oil-paint, I assume that is your intended use.

Actually, the BLO that is sold  in art stores is the same stuff that is peddled in hardware stores, be they large or small.

So you can use the BLO from the gallon cans for anything that you might use the BLO purchased from anywhere else.

Edit:

Note that not all linseed oil is "boiled linseed oil".  BLO is not even actually boiled, but has additives that cause it to dry faster. Raw linseed oil is a slow drying product and may be refined.  Stand oil is heated and is lighter in color.

Most hardware stores carry only BLO.

Raw linseed oil is harder to find except in specialty stores (e.g. art supply houses).  Art stores are likely to carry multiple forms of linseed oil, but the one with the "Boiled linseed oil" label contains the same stuff as from the hardware stores.


What would happen if I machine laundered dry clean only fabric before making it into a garment?

I think it really depends on the fabric.
If the manufacturer of the fabric states that it should be dry cleaned, that's probably a signal that they're serious about it. Silk and wool can often be hand-washed in very gentle shampoo as a way of pre-shrinking the fabric... but some fabrics simply don't tolerate washing well. They lose their look or shape when soaked in water, so even pre-washing won't do much for you. Another consideration is colorfastness... apparently some brightly-colored silks can lose their color when washed.
From a dry cleaner's website:

The first determination is whether or not the fabric can be submersed in water. Fabrics such as cashmere and wool are susceptible to losing shape in full submersion and will likely shrink, so typical washing should be avoided. Another gentle fabric is silk. An extremely delicate material, silk can be hand washed; however, it should never be complete submerged nor agitated in a washing machine.  [. . . ]
While some fabrics may be washed, like certain chiffon, satin, and lace articles, additional care must be taken when ironing. A dry cleaning process offers a safer alternative to typical ironing, making it more effective for a wider variety of products.

If you're making a structured jacket and you want to retain the crisp lines and smooth drape, you probably don't want to machine wash your jacket as it may destroy the cut and the work you put into it. Now, if it's a casual jacket that doesn't need to look "neat" or "sharp", your washing regimen likely won't matter but keep that in mind.
I found another quote that sort of peeved me - it's tangentially related and I thought it might be valuable here...

Q: I was wondering, does it mean all the Big Designer Labels pre-launder all their fabric before production?
Graceful Sewing
June 1st, 2015
No, they do not. That is often the only reason that garments purchased from them have to be dry cleaned. If they had preshrunk the fabric, we could toss it in the washer and it would do fine. But because they skip this step, we are left with huge dry cleaning bills so they could save a few dollars and make us think we are. Also, on clothing that is washable, you will often find the the seams are a just little gathered coming out of the dryer, or that the garment is not quite on grain like it was (that why our garments tend to look old quickly). The best way to handle these is to gently tug on each end of the seams (particularly in knit fabrics) and straighten it out while warm. The lay the garment out flat or neatly fold it without wrinkles and let it set until it cools completely. If the garment is twisted off grain, gently tug on the two shorter corners to pull it back into alignment and then proceed as above. Your clothing won’t have the advantage of custom-made (and preshrunk) does, but it will look better and last longer.

So, my interpretation here is that, yes, to a degree, if the fabric is pre-washed, it may affect the final outcome's washability... so it's not only the fabric type that determines the washing method on store-bought clothing.
Another interesting source is on The Laundress where they go through various fabric types and garment styles to hash out what can and can't be washed at home. The ones that relate to fabrics specifically include

Don't wash viscose (it shrinks, often unevenly)
Don't wash polyamide blends (they grow)
Don't wash "structured" items - ties, blazers with shoulder pads
Don't wash suede & leather - if marked "not washable" or "Dryclean only"
Don't wash fur with skin

There's actually not too much on this list, amusingly... so it seems that, provided you do some research on how to wash anything else properly (that does not mean you can toss everything in your washer, though), you should be able to avoid dry clean only clothes to a large extent.


What does a pigment's richness refer to?

A paint that is "Rich in pigment" has a higher concentration of pigment (and less white filler). A paint that is rich in crimson or ultramarine pigment has high saturation. A paint that is rich in umber or black pigment has low saturation.

So the term "rich" can't be consistently translated into the "hue, saturation, value" system of designating colors. Some rich colors have high saturation, and some rich colors have low saturation.


Which glue should I use to attach paper to glass?

We make beer.

We occasionally make labels for that beer.

The easiest, best cheapest way to attach the labels is... ready for this... you sure???

Milk.

Don't know why, don't ask why. It works. You won't be able to wash the bottles without the label coming off but if you're brewing, by the time you're washing the bottle, you probably want the label to come off.

Because you're getting the entire label wet, it will evenly discolor but I haven't had major issues with the colors running or smearing. There's a helpful guide for it on "OnlineLabels.com". They even have a comparison photo of a sticker label next to a milk-application.

Of course, they want you to buy their labels, so they make it sound onerous to do the application process. We've done a full 5 gallon batch pretty easily, so don't be too concerned about it. And if you try it once and hate it, well... you could switch to sticker paper. Apparently a lot of people use Avery brand sticker labels (the ones you might use for mailing).

Based on their instructions, they have you dip the paper in the milk... we found it was much easier to use a basting brush (or a cheap 1-inch chip brush from the hardware store) than to try to dip the paper.

For other options, see the related/identical question to this on our Homebrewing site - here. This answer, specifically, talks about using milk.


Paperweights used to hold down Art, Posters, or Maps for framing

Weight bags/Paper weights to hold down art
as pkamb said in the commments.  Also, I searched "paperweights to hold down art" and the ones you're looking for are there. Take a look at it, that's what you're looking for.


What type of glue will work well on wood and metal?

2-part epoxy is my usual recommendation when it comes to mating different kinds of materials together. That is usually one of the selling points.

I would caution with the use of Gorilla Glue for this. While is might be a viable choice you need to be careful of its expansion properties. If you do try to use it make sure you clamp appropriately and clean any excess that seeps out. That is general advice for gluing in general but you really don't want warping in the final product here.

Depending on the size of the veneer and how it is prepared there is a chance for small pockets to exist where the glue could expand. As long as you clamp firmly for the duration of the setting time you should be fine though.


Achieving Smooth Concrete Texture with Tiny Bubbles

Surface texture
The fineness of the sand determines the surface texture (ignoring texture created by the surface of the mold or through a treatment like brushing the surface).
On something like a sidewalk, where high traction is important, relatively coarse sand may be used or combined with finer sand, resulting in a gritty surface.  Finer sand is used for purposes such as building construction.  Non-decorative concrete walls are pretty smooth but "flat" (as in not glossy).  For concrete countertops and some art casting, extremely fine sand is used.  If the mold has a smooth, polished surface, the resulting concrete can look like shiny stone.
The triangular castings in the top picture look like ordinary, general purpose concrete (although the units toward the back look like they were made without using good technique that an experienced concrete worker would use for structural purposes). The planter in your bottom picture looks like it was cast using a general purpose mix, either a concrete topper or one containing very small aggregate.  The irregular rim and non-uniform color suggests this could have been mixed with some other material, or it was a recipe mixed from scratch.  But the surface texture looks like the sand particle size used in a standard, general purpose mix.
Bubbles
Concrete has bubbles.  Air fills the space between the particles when it's dry and air gets blended in when it's mixed with water.  Concrete starts with bubbles.  If you don't do anything to it, it will harden with bubbles.  For concrete structures, like buildings, bubbles affect the strength and longevity.  So after fresh concrete is poured, it is vibrated to help the bubbles work their way to the surface.
On something like building construction, the forms are often very tall, so even pouring and working in layers, it's hard to eliminate all the bubbles.  With art casting, the craftsman may not have been trained in concrete techniques.  But on a thin-walled casting like the planter in your bottom picture, it's harder to get all the bubbles out.
It also could have been intentional to give it the appearance of crude, poured concrete, which is a different look from the smooth surface of clay (they could have achieved a clay-like surface texture in concrete with a different mix and technique if that's what they were going for).
However, referring to the cast triangular item in the upper right of the first picture, that has an unusual amount of bubbles -- more than concrete normally has.  That one looks like the craftsman may have been experimenting with partially foaming concrete.  They may have used additives, and probably whipped the concrete more than blending it.
Terminology
If you see hardened concrete with visible bubbles, the term for that would be "concrete".  A more precise term for concrete with the smooth, flat surface texture like the items in your pictures would be "general purpose concrete".  The technique for achieving that surface texture would be pouring it into a form or mold with smooth sides and then leaving it alone until it's hard.
Basically, what's pictured is not special in any way and doesn't have terms for a special mix, technique, or finish.  It's concrete with no special treatment.  It would take a special mix or technique to make it look different from that.


If the light is coming from a candle, or group of candles, you're going to have very dramatic chiaroscuro lighting.

Shadows should be very black, with not a lot of grey tones.  Keep in mind that only the elements very close to the candles are going to be visible.  Also, candles have yellow light, so basically all colors are a shade of yellow or orange.  Blues and purples will be just about black.


What is the correct converter to fit my Inoxcrom fountain pen?

Seems like everything online says these use the Standard International size cartridge. There are some complaints of leaks though unless you get them from the original maker.

If you have an old original cartridge, you could try cleaning and refilling it.


Start with acetone (nail polish remover) and see if that does the trick. Agitating with a Q-tip can speed things along. It all depends on what the coating is, but acetone won't hurt the copper so it's a good place to start. If it works but isn't fast, you might try soaking it for an hour or so.

A more aggressive approach would be oven cleaner, but it's likely to remove any patina from the copper and shouldn't be left on there too long. Also make sure to rinse thoroughly with water afterwards to remove any caustic residue.


A needle may not be as stiff as you think. One reason a needle seems so stiff is that it's short. A needle of the same diameter and material that was a foot long would not seem stiff at all by comparison. This is just the mechanics of materials at play.

The design problem is a trade-off between wire diameter and material strength. The stiffness of the wire is increased with the wire diameter and also by the strength of the material; a wire of stronger material will deflect less than one of a lesser strength, given the same diameter.

The strength of steel is strongly affected by the alloy and its state of hardening. At the low end would be baling wire, which is mild steel (low-carbon) which cannot be hardened. At the high-end would be tool steel (chrome-vanadium alloy perhaps) that was hardened to maybe 60 Rc (really darn hard). These would exhibit really different deflection characteristics, from bending (permanently) with mild hand pressure to really making you work for it and probably snapping before taking too much of a bend.

A generally good compromise on these is available in music wire, as Matt mentions. Music wire is high-ish carbon steel hardened to a spring temper. This makes it good for springs, which is what a piano string is. It can be made harder, but this comes at the cost of increasing its brittleness. (If you snap a good needle with pliers you'll find that it snaps suddenly, aka. a brittle failure.)

Additional strength can be obtained using a tool steel, which I expect what the best needles are made from. This is most easily obtained as so-called "drill rod". It is supplied unhardened (but still quite strong) and can be hardened to your specifications using a propane torch and either water or (vegetable) oil.

None of these options will be absolutely rigid over any distance. You'll need to decide where to trade off a graceful curve with wire thickness. If you can prevent the wire from rotating, you may be able to "pre-stress" the wire (bend it upwards) such that it appears quite straight when loaded.

I would start with the music wire. It's much cheaper and easier to find. If it's important enough and music wire won't get it done you can look into tool steels.


Do reference photos have to be the same size as my final drawing?
No.
Typically for individuals that begin learning to draw, they would start out in a grid method. To get a feel (muscle memory) where everything is proportionately going to be placed. Over time the hand and eye coordination will start to catch on over time. There are also other methods, such a projectors, or even tracing tables to help assist in large scale pieces of art.
Printers and tablets can be a good idea. It is common for artists to print out pieces of art, and grid on the printed piece of paper, to help with proportions as well.


Perhaps you could make your own version by mixing up a ground that you could paint onto less expensive paper. I am pretty sure Golden makes things that you can mix into their acrylic mediums to add tooth to the surface. If you build up a thick enough base you could hand sand that surface to get the different grades that Uart provides.

It would be tricky to match the even consistency of Uart but rolling your own seems the most economical approach. It also lets you control the base color of your surface as you can pigment the ground you are applying.


How to prevent my cutting mat from warping?

Taking each aspect in turn:

Covering the mat with something white, a sheet of paper, a fabric sheet, a light colored towel, may provide protection from any thermal related warping. If the mat is warping in a manner that causes it to lift upward in the center, generally speaking, you may be getting "top layer" thermal expansion.

Hammering is less definitive, unless you can see patterns in the mat. If you are hammering in a regularly visited location, it may be splaying out under the mallet or hammer, causing a sort of bottom layer expansion, which would result in the edges curling upward. It would take substantial hammering in the same location to accomplish this.

Small sections of localized bending could be the result of hammering. It would result in an irregular form of warping, perhaps dimples in some areas, bumps or moguls in others.

I found this on the Blick web site:
"If your Blick Cutting Mat should become bent or distorted, simply heat it in sunlight or hot water until it becomes pliable and then lay it flat until cool."

You could consider to play a hair dryer over the surface to "relax" the warping or bumps. I would recommend against anything as powerful as a heat gun, as it has the capabilities to melt the surface in a very short time.

If you are successful in flattening the mat, shade and cooling air flow are your friends.


What are practical advantages and disadvantages of learning to use both hands to draw?

I meet with a small group once a month to "do art". Each month one of us is in charge of the lesson. We just did pencil sketches using our dominant and then non dominant hand. We were all amazed- everyone liked the non dominant drawings better. You are more detail oriented and try to draw to perfection w your dominant hand. The non dominant  drawings were looser and more free. It is considered a good practice to do to increase your awareness to detail, your drawing skills and good for your brain.


How can I fully bleach a polyester shirt?

Bleaching works "as expected" for natural plant fibers (e.g. cotton). Polyester is actually a plastic, and bleaching will not have the same effect. I expect one (some?) of the following:

no change;
some fading, potentially not uniform;
(partial) destruction of the shirt, as a result of the bleach attacking the plastics. Even worse, if there is anything natural hidden somewhere (some stitching, logos...)

Bottom line, I would not even try. A new white shirt must be quite easy to find, and quite cheap.


Can I melt or weld broken ABS plastic back together?

Back in my University days I worked at a place that used to modify vending machines to allow 12oz cans to be vended in 16oz machines. They did this by adding ABS blocks to the racks using a very liquid substance that lightly melted the ABS and allowed the bond to form. It was a very tight bonding.

The closest I've found to that, and probably your best bet if you don't mind buying it, is Plastruct Plastic Weld. This may even be the hobby version of the stuff I used back in the day, the effect is the same based on the description.

I also understand that acetone (otherwise known as nail polish remover) can have a similar effect on plastics of various sorts. If you have some junk plastic to test with, this is worth trying. You're not using a lot, you just need to dip the parts to be bonded in or brush it on with a non-plastic brush or cotton swab.