So what's new in my life? 09/11/18 - Just got back from vacation.

I just got back from a much needed and really great nine day vacation to my remote Arizona property. It was a really restful and relaxing visit. I got a lot accomplished while I was there, but still found time to just goof off and have fun too. I got to do some astronomy, even though the weather was pretty cloudy most of the time. Here is a 50 minute exposure of M101. It turned out pretty good. Click the photo to more photos and read about all my adventures from this vacation on my Travel and Vacation Photos page.

08/19/18 - Beach Re-Nourishment at Indian Rocks Beach, Florida.

My girlfriend and I like to take long walks on the beach in the evenings after dinner. We try to get out there at least a couple of times a week, and we walk at least four miles each time. A four mile walk in the sand is quite a workout. Plus the beach at night is cooler, less crowded, and more romantic;-) Anyway, we could see the beach renourishment happening off in the distance at the far northern end of our walks. Last night we decided to get a closer look. We parked two miles further north than usual and started our walk from there. It was still 1.3 miles before we reached the area where they are currently working.


There is some sort of large barge about a mile offshore pumping sand slurry through a pipe about four feet in diameter onto the beach. A big machine separates out any debris, and just let's clean sand and water flow onto the beach. Two huge bulldozers were spreading the sand around. They were about doubling the width of the beach to provide for protection from storms. We continued walking for another 0.7 miles beyond the work zone before turning around and heading back to the truck. The new wider beach on the far side was really nice. Since we are both into paleontology, we wished we could have got a look into the dumpster all the debris separated from the sand was being dumped into. We could hear stuff banging its way down the length of the pipe. There were probably a lot of nice shells and maybe some big shark teeth and fossils in there. No dice though. A guy was patrolling the parameter of the work zone and shooing everyone away. Gotta find out where they dump that stuff.

08/14/18 - Facing off a plaster mold and lost foam casting in Aluminum.

Last weekend used my Woodpile CNC mill to face off the top of a refractory plaster mold I had cast earlier using the foam mold in the below video from 7/14/18. It was my first experiment with milling plaster. I dished out the top surface to f/4 so the resulting cast glass telescope mirror blank would have a constant glass thickness. It went well, but I am concerned about tool life. The tool seems to have been dulled a lot by the cut. The refractory plaster I use for molding glass is filled with silica and alumina to make it more heat resistant. That also tends to make it dull cutting tools quickly. I'll keep experimenting though. Maybe cutting the molds out of disks of plaster will be a better method than cutting a pattern in foam and then casting the plaster in it. Time will tell.


I also did a little lost foam casting last weekend. I needed an aluminum disk 1/2 inch thick for another project. I didn't have any flat stock on hand that I could cut it out of, so naturally I thought of firing up the foundry and casting one. It went surprisingly well, or at least seemed to at first. It always surprises me how easy lost foam casting in ordinary sand is. On the left is the kind of pattern I was using. On the right is the result. I don't know if the three soda straw vents were really needed, but they take no time to add, and they are easy to cut off the finished castings.


Here I have cut off the vents from the disk casting. I also sawed off the riser in the middle later. I then center drilled the disk and screwed it onto an arbor so I could mount it in a lathe. My plan was to take the disk in to work early on Monday and clean it up on the toolroom lathe we have there. I had also cast a large round rod of Aluminum using a bean can as a mold. I can turn it down to make any large parts I would need large diameter round stock for.


Things didn't go quite as planned. I knew the disk was a little warped (kind of like a potato chip) but didn't think it was too bad. Once it was turning in the lathe though, I could see just how bad it really was. There was no salvaging it. I tried casting another