How to Stiffen Leather. To stiffen leather, you need to alter its structure at a molecular level. This is usually done by combining heat with water or wax, but there are several different ways you can go about doing so. Soak the leather in.
Leatherworking tip- Trying to wet form leather and dont have a bone creaser? Grab a cork! Its firm enough to mould the leather but soft enough to conform to the form underneath. Itll even burnish as the leather dries!