www.depronusa.com sells 6mm white depron foam, that is what you will need to make a foamy
www.depronalaska.com also carries the same stuff is Depron USA is sold out.
If your looking for foamy locally, you won't find Depron, which really is the best stuff. Fanfold (blue foam) can be found at Lowes I know for sure, maybe Home Depot I am thinking, and is cheaper.