I've read everything I can find on here about foam.  Here's the deal: regular 1/2 foam (the blue/green foam from the fabric store) is not holding its shape in the head of the puppet I am making.  So... what kind of foam do I need?  I've looked at EVA foam mats (the anti fatigue ones), thought about going to a foam company (there are several in our area) and asking them, etc.  Would 35 PPI hold the shape better than the foam I have?

Doesn't it depend on the kind of shape you're wanting to make? I remember trying to make a bell-head shape, for which someone here (most likely Shawn) pointed out that removing part of the foam would help hold the shape.

Not sure if this is applicable, but I'm wondering if that detail is helpful in knowing how to fix the problem...

It is true that EVA or L2000 will hold it's shape better, but depending on the design of the puppet it can be a bit two ridged for operation of the mouth.  Often what I do is combine the two. The outer skull can be of the more pliable foam but then I use the denser foam both for the mouth plate and for supports on the inside of the head. Say you have a round head shape and it is collapsing on you. You could cut a half round of EVA and then glue it on the inside of the head to help support it. Here is a picture that illustrates adding support for something that is collapsing. These where large Christmas tree body puppets and the "branches" kept spreading out and collapsing.  We went back in and added trangle wedges on the ends of each to help support the form.



You may even notice that there are round metal hoops. These where actually original to the costumes although we did have to reattach them because they had started to pull out. This is another example of how you can support foam so it holds it's shape. You don't always have to use foam as your supports.

What size is the head? I have used regular density .95lb white 1" foam even for an over sized mascot head. The key is to make the head from several pieces glued together, kind of like the slices in a beach ball.  This gives it more strength.  If you look at our custom creations page as well as most of the blacklight animals, these are all made from the 1" white.

Julie