Spray Foam Feet?

I have become fairly curious over the aspect of spay foam feet. I have been wondering about how safe it is. Ive looked in the memories and saw aborted spray foam heads but never anything about feet. I was planning to cast it in a latex mold and then covering them in paper clay so that they dont get squished. Is it a good idea? I am not a fan of carving foam, so if it is not safe to make them out of spray foam then what is a good direction to go in? Thanks for your help in advance!