What is the fuzzy stuff on the inside of HVAC vents?

As part of the e21 refurb, I'm taking apart the HVAC to clean it all up, etc.

The vent panels (the parts that open and close inside the HVAC assembly) are covered in some kind of foam stuff, but it has totally deteriorated and basically dissolves if you even look at it crooked. I assume this material is there both to seal (it extends past the edges of the metal vents) and to quiet things down.

Anyhow, I need to replace it. Anyone know where to get this stuff? It looks like it is applied in a self-adhesive sheet.

Here's what I'm talking about:

I cut pieces of felt from the craft store to fit and glued them into place.

All I know is it comes off in little bits after a couple decades and flies into your eyeballs when you turn the fan on.

Lots of folks use billiard felt.

Thanks, good ideas!

I believe that acts as a sort of filter. I reckon air conditioning filter foam may work too. I wonder what the restoration guys use...

Here is what one of my RX7 peeps did. Nice restoration of the blower motor and heater core. http://www.rx7club.com/3rd-generation-specific-1993-2002-16/heater-core-restoration-w-photos-1001759/

The foam is three fold in purpose.
It softens the shutting, so when it opens and closes it doesn't make a clapping noise.
It acts as a seal for the door.
And it is also a general noise reducer (same concept as carpet on the walls of a theater.)

hmm, I wonder if flocking those pieces would be effective....I have plenty of flocking stuff left over from the e30 dash

you think it is bad there.. BMW puts that same stuff inside the airbox.. yes, after the filter. And yes, it does fall apart and get sucked into the engine

Interesting. I had the airbox apart on the e30 many times, as well as a full clean-out of the MAF/AFM, and didn't notice any of it (other than the foam seal from the airbox to the IM elbow, which I replaced).

the E36 has a fully "foamed" airbox

For those who suggested felt, good suggestion. I stopped by Michael's Crafts on the way home and got a couple sheets of their "thick" felt sheets (about $1.25 each). They are self-adhesive and the adhesive seems very tacky and good, not cheap stuff. Anyhow, came out great so thanks again :)

here's the stuff in case anyone cares