Polyurethane resin

From CosplayWiki

Polyurethane resin is pretty harsh stuff to work with. It gives off strong chemicals and should be used in a place with proper ventilation. It comes in a big metal can similar to paint thinner and has a small tube of catalyst which is used for hardening. The little tubes of MEKP (Methyl Ethyl Ketone Peroxide) can be bought separately. Each brand will give their own ratios of resin to MEKP but it's typically about 8 drops per ounce of resin. The good part about this type of resin is it dries fast and the ratio is more of an art than a science as the catalyst only creates a chemical reaction that causes heat to cure the resin. If you're a little off in your mixture it will still harden it just might do it too fast or take a long time. This stuff will eat away pink insulation foam, so don't use it on it unless you seal it with something first such as latex paint.

Information provided by Alex Evangelou