I know this is a really stupid question on my part, but what exactly is a cake drum made out of? Is it just 2 cardboards glued together, wrapped in foil or what?

I have found cake drums made from two different materials. Some, usually the silver ones, are made from a very thick piece of foam core board - I believe it is 1/2 inch thick.

When I go to the out of state supply stores, I am able to find them made of 1/2 inch thick drywall.

Theresa