Sealing tray area before re-foaming? "Flex Seal"??

[McDog]

1.Idea stealer.

2.if it works on a screen door then it will Flex....heck it's even called flex seal.

3.you can't get every crook and crevice with 5200.

4. Expanding foam gets wet and polystyrene sheets do not so polystyrene is a permanent solution with drain holes.