Duckster'

I don't have the answer but I LOVE the question. I was in Hobby Lobby yesterday and was checking foam. They had 2mm and 3mm for .79 and .99 cents for a 14 x 17 sheet and I kept thinking it sure would be nice if I could find some 1 mm. So, sorry I don't have a source but I'm going to tag along and hope someone can enlighten both of us.