I've been using biodegradable materials to recreate another one of my old synthetic-materials masks designs. This picture shows the results of mixing natural polymer starch with a recycled paper pulp material:
Those are the exact same ingredients that I used as a "spackle" coat to smooth the surface of the paper mache magpie mask, and to detail the nose of the giant paper mache bear puppet. But in this case I mixed up a much larger amount and press-molded it into a plaster mold.
If you are familiar with the masks I made for my old business Goblin Art, you would have seen the original version of this mask made from synthetic liquid neoprene rubber, slip-cast into the same plaster mold.
Original neoprene version:
The neoprene mask has more detail than the bio-plastic/paper pulp mask, but I will try a finer-grained paper pulp next time and see if that makes a difference.
Regardless of the difference in detail though, I really feel that this is a huge breakthrough--to finally be able to recreate one of my most complex original mask styles with natural and biodegradable materials. Plus much more affordable and accessible materials! But I plan to make (and stress-test) more masks with this technique before I create a tutorial.