I was wondering if anyone has experimented with any other foam other than what Project Puppet offers.For instance, a local Hobby Lobby near me has PolyFoam sheets pretty cheap. The only differences are that it's poly foam and it's 1 in. thick instead of the 1/2 in that P.P. offers. IS this difference in type going to affect the puppet? What about the thickness?
It's really tough generalizing about reticulated foam and poly foam because those are catch-all terms for different types of open cell ("sponge-like") foam. There are a lot of variables, especially thickness of the foam, the chemical formula that's used to make it and the number of PPI (pores per inch).
I really like 3/4" inch reticulated foam for most things, although 1/2" works well at a smaller scale sometimes. Years ago you could find 3/4" poly foam available commercially, but I have not seen it in that thickness for many years. The foam I have was ordered wholesale and custom cut in to 3/4" sheets by a manufacturer, which is not really a cheap way to go.
One inch poly foam tends to a little bulkier and heavier than reticulated foam. Not terribly so, but it does make a difference. Sometimes that's a bonus if you want to make a character look especially round, or full.
I find most 1/2" poly foam a little too flimsy, but again it has its uses.
Most experienced puppet builders don't just work with one kind of foam, they choose a material that best suits the puppet they are building. My advice is to buy small quantities of different kinds of foam (as much as you can afford), experiment with them and see what the pros or cons of each are.