Where to get foam for under pcb?

[___q]

On some of the used custom keyboards I've acquired, there has been a piece of foam in the bottom of the case under the PCB, presumably to deaden some of the bottoming-out sound by filling up that hollow space.  These keyboards also sound great.

I have a Filco in one of the vortex aluminum cases which I did not put any such foam in, and it doesn't sound nearly as nice as the customs.  Where can I buy foam like this which is safe for the pcb?  Searching on Amazon for words like 'foam' and 'memory foam' isn't particularly helpful.

Thanks!

[damorgue]

I believe the one commonly used is actually a shelf liner.

[jcrouse]

Michaels (hobby store). Cheap and many nice colors to choose from, if that matters.

[damorgue]

http://www.amazon.com/Grip-Shelf-Drawer-Liner-Black/dp/B000KFSOFI

Rubber shelf liner, like the one above is the one I was thinking of.

[CPTBadAss]

I used a rubber/foam kitchen drawer liner from Target.

[Halverson]

I line the bottom of my boards with nudes of CPTBadAss.

[The_Beast]

I line the bottom of my boards with nudes of CPTBadAss.

I see how it is!