My apologies if this is posted under the wrong topic section. I'm tearing my hair out and stuck. Unfortunately the mustang forums I post to had no replies.

I'm working on my other girl's heater core (91 mustang), and decided to redo all the foam on the blend doors. I saw on the interwebs that older cars supposedly had used 100% wool felt prior to foam becoming the popular material of choice. So I bought some, and stuck it on. Unfortunately the felt is too thick and it's not letting the door make a good seal when closed, see pic below. I have not been able to locate any thinner 100% wool felt. Supposedly the readily available 100% polyester felt found at craft stores will deteriorate after a few years. I also read the open cell foam from the big box stores would also fall apart after a few years. I really do not want to do this job twice. So here I am, with less hair and stuck.

Does anyone have any tips or a source for some felt or foam that would work for this application? Any insight would be greatly appreciated.

Thank you,

Jorge

Click to view attachment

Maybe it was wool in the 60s mustang but the 914 uses foam. All the later cars I've seen have been closed cell foam which is what Vintage Air & others use.

In that application I doubt it was a whole sheet. More likely just the perimeter.

Hello Jorge,

Maybe filter material (filter fleece) that is used to protect fans in tooling machines from dust will work? Should be available in industrial supply stores.

Greets, Arno

Chris - I'll give Vintage Air a call. Maybe I can buy some foam from them?

Arno - Good idea with the filter fleece. If I can't find a foam source I'll buy some and see if fits.

Thanks guys!

It's readily available on amazon/ebay/aliexpress. It's also used in car sound deadening with PSA (Pressure Sensitive Adhesive).

example

Felt that is used for the bottom of furniture legs. Different thickness and it is very dense.

Take a look


Bob B

Can you slice that layer of felt in half? Make it half the thickness?

I googled “automotive wool felt” and found material as thin a 1/16”.

Unfortunately, it’s sold by the yard, so probably way more than you need. Try an car upholstery shop?

I knew you guys would come up with a few different ways to attack the problem! In between the different wools/felt or foam one should be the right fit.

I'll report back once I test them out and find the goldilocks answer.

Thanks all!