replacement foam for blower unit flaps

[devolution]

I found something that works really well to replace the foam that covers the flaps inside the HVAC blower unit. The old stuff, as you may have encountered yourself, was disintegrating badly and leaving a mess inside the vent system. I spent a good deal of time cleaning all of the vents out and didn't want more black crap blowing into the car, so I had to find something of the basically the same density and thickness. It took a while to find someplace that sells different varieties and also sells in small quantities. The one I decided to use is this: http://www.mcmaster.com/#86225K11 . I got one sheet of that foam (24" x 24" x 1/8") with no adhesive backing. They have an adhesive-backed one also that might be easier to use, but I wasn't sure how well the adhesive would hold up over time.

I used a putty knife to carve off the bulk of the old stuff and then Citrasolv to strip the remainder and the old adhesive. After the flaps were dry, attaching the new stuff and cutting it to size was simple. I used 3M weatherstrip adhesive to attach it. This foam looks very similar to the original and works great when reassembled.

One thing to keep in mind when ordering single sheets from McMaster Carr: they package it flat and the box they set me was huge, and even though the sheet was only $4.32 and weighs next to nothing, the shipping was $19! I called right after I received the receipt and complained about the high shipping cost (this was before I saw the box), and they were cool enough to refund me the entire shipping cost. once the box arrived, I realized why it cost so much (though distance definitely was a factor since I'm on the West coast), so you might want to inquire with them before placing the order about whether there's some way they can ship it either folded or rolled up so it's cheaper.

this is what the plastic looks like with old foam stripped off (sorry, quality isn't great):


and here's a side with the foam attached and cut to size: