I'm in the process of fixing the cheap plastic hinge AC blend door on my 86 F350. I've search the forum here and found some that used like Home Depot foam, but was wondering if anyone has come up with any better foam material since then. I need to get like a piano hinge for the door, but was wanting to cover the door with some good foam stuff similar to the original Ford one.

 

I think I used packing foam from a computer monitor.

Take a look in a local hobby/art supply shop e.g. Hobby Lobby or Michael's.

 

I have used cap tape. The stuff that seals the cap to the pickup bed

 

You can get 1/8" or 1/4" thick foam rubber from your local Orchard Supply Hardware in what ever size you'd need, which works great for this use. I've also seen a different material at O'Reilly's sold as an oil absorbant foam mat which works great for the sliding door air vents on the non-AC trucks.