I would comment that not all foams are created equal.
I once used some kitchen no-skid drawer liner material from a dollar store in a small tote box I had in the trunk.
Went back weeks later, the tools that had plastic handles had sort of melted the material, leaving dots of the foam stuck to the tools.
Some foam like the kitchen drawer liners will react w/paint, too.
I seriously doubt the better closed cell foam or whatever it is would have those problems, and would be much
better at resisting damage from chemicals than the junk I was dealing with. All the same, I think it would be a good idea to get a sample piece or find out the exact material it's made from and look up the properties to see if it'll hold up to garage use.
A good choice might be neoprene, like HERE
, but darn- the PRICE!
I'd like to use the 1/4" and 1/2" for the cut out sheets, then back them with 1/8". Would make for a nice "finished" look.