Ok here is the red neck, el-cheapo coming out of me. LOL
I am wanting to make an old Samsonite brief case into a lockable pistol case.

So I am looking for a source of that grey egg crate foam you see in most gun cases. (or any color)
It would have to be at least 3" thick 18"x24".
It does not neccesarily have to be "gun case" foam.
Any egg crate foam should work.

While it won't likely be egg crate foam you should be able to buy 3-4" thick foam of different densities from a sewing supply shop. They generally stock several different types for pillow making.

hangunnr

You'll find 3-4" foam at places like Home Depot, hardware stores, marine supply outlets, and upholstry shops. The latter may also have scraps more than big enough, cheap too. 1" scrap foam can also be had at carpet outlets, 3-4 layers on each side of the case should work. Lay the top layer out and trace your guns on it, cut out to inlet, or leave whole. Just glue all layers in when you're done inletting.

Keyman (non sibi sed partiae)

check out a home health store, they should carry the egg crate foam , it is used for bed ridden patients.
nmhunter

We used to get egg crate foam at the local Army/Navy store all the time. reakin

Local surplus store has it here. Also check with your local upholstery shop, they got lots of stuff like that in all different thicknesses.