Both home Depot and Lowes sale the nice foam, it's pipe insulation. Just be sure you get the nice dense foam and not the other stuff. Not sure what the two called but they are both for insulation of pipes, I think the good stuff is used on air condition pipes.
I just received some EPDM foam tubing from Granger for the airplane holders for Lg. prop planes at our field and it is the perfect material. The tubing has a soft foam inside and a skin on the outside. It's actually used for air-conditioning piping. You can order it slit or non slit depending on you preference. I ordered 18 feet and it was $40 with shipping
Thanks I will look for the EPDM. The stuff I have is like the pool noodle noted (come to think of it) and in one use it smashed as flat as pool table felt.