Fill a large bucket or sink with cool to room temperature water. Immerse the leather in the water for about 10 minutes, or until it becomes thoroughly soaked.


Note that this process works best when used with vegetable tanned leather.
You can technically stiffen the leather by soaking it in nothing but room temperature water, but it will only become mildly harder and you will not be able to shape it. The addition of a hot water step will allow you to make structural changes while hardening the leather further.;
, As your leather soaks, fill a large stockpot with water and set it on the stove over high heat. Continue heating the water until it reaches a temperature of 180 degrees Fahrenheit (82 degrees Celsius).Use an accurate thermometer to keep track of the temperature. If the water is too hot or too cold, your results can vary dramatically from those described here.
If you do not have a thermometer, you can gauge the temperature of the water by slowly heating it on the stove and testing it every minute or so with your bare hand. If you can keep your hand immersed in the water, it is safe to use that temperature for your leather. Once you can no longer bear to keep your hand in the water for more than an instant, remove the water from the heat source and do not allow it to get any hotter.
Some people prefer to soak the leather in boiling water. Doing so stiffens the leather at a faster pace, but it also gives you less control. The resulting leather can become very brittle and may be unevenly stiff across its surface.
 Pull the leather out of the cool water and immerse it in the hot water. Let it remain there for a few minutes.


After the first minute, you should already see the leather darken and curl.
The longer you soak the leather, the stiffer it will become. If you soak the leather too long, however, it will be more brittle when dry.
When using this method, soaking the leather in hot water for 30 seconds after it already darkens will result in a piece of leather that is hard but not inflexible. This means that the total hot water soak time would be about 90 seconds. Leave the leather in the water for a longer period of time if you want to make it stiffer.
 When you pull the leather out of the water, it should be fairly flexible. If you need the form the leather into a specific shape, now is the time to do so.


When wet, the leather will be stretchy and easy to form. This stretchiness will vanish within the first minute or two, though, so you need to work fast if you plan to stretch it out. The leather will still remain flexible for up to an hour after the stretchiness fades away, though.
 Let the leather sit out at room temperature for several hours. After it dries, the leather should be notably thicker and stiffer.


Stiffened leather will also shrink, so the piece you started out with may not look as large when you finish the process.
Soak the leather in cool water.
Heat a second pot of water.
Dunk the leather in the hot water.
Shape as desired.
Allow the leather to dry at room temperature.
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