Thanks! I used 1" pink foam from Home Depot and cut out the shapes with a bandsaw. I think the coloured layers of paint protected the foam from melting when I sprayed on the clear coat. One of the hills had a felt spots where the spray caused some melting but nothing major. Not sure why it happened to just one and not all the rest. There must have been a few tiny missed spots when I painted it that left the foam exposed to the clear coat.