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Sherri Zann · 02-26-08, 01:17

Yeah, there is some outfit in Manila (?!) called "AutoFoam" that shoots expanding polyurethane foam (from Germany, probably Wurth Chemical as source has been the speculation) into the car pillars and sills. There is a bulletin board where a number of people either had AutoFoam do this, or they took Great Stuff and did a DIY job.

Great Stuff is polyurethane-based, and yields a closed-cell foam. Make sure you don't use a substitute which is latex-based, because this creates an open-celled foam that can absorb water.

Also, here's a warning from the door and window version of Great Stuff (GS): "Reacts slowly with water, releasing carbon dioxide, which can cause pressure buildup and rupture of closed containers. Elevated temperatures accelerate this process." My concern would be if you really sealed a hollow section, having the car heat up in the sun and potentially push out a panel. Of course, that's what you are trying to avoid by using the w/d version that has minimal expansion, compared to the gaps and cracks GS.

Also, GS is about 20-30% isocyanate, and you don't want to be breathing the fumes while it is curing.

I was very, very tempted to shoot GS into the A pillars and the sill. I haven't so far because of my concern that I might end up trapping water inside the car structure and helping it rust from the inside. For example, I have a sun roof. And there are all sorts of other ways that water can get inside structures. I wonder if the open pillars are part of drain paths. I may examine the sills and pillars more carefully from below to figure out how this really works. I think the idea of foaming these hollow areas is potentially excellent, both for structural rigidity and noise-reduction. The guys in Manilla were very enthusiastic after doing it!

02-26-08, 01:17	#8 (permalink)
Sherri Zann Lurker Extraordinaire Sherri Zann is offline Join Date: Jan 2002 Location: Durham, NC Posts: 234	Re: Sound proofing to reduce road noise Yeah, there is some outfit in Manila (?!) called "AutoFoam" that shoots expanding polyurethane foam (from Germany, probably Wurth Chemical as source has been the speculation) into the car pillars and sills. There is a bulletin board where a number of people either had AutoFoam do this, or they took Great Stuff and did a DIY job. Great Stuff is polyurethane-based, and yields a closed-cell foam. Make sure you don't use a substitute which is latex-based, because this creates an open-celled foam that can absorb water. Also, here's a warning from the door and window version of Great Stuff (GS): "Reacts slowly with water, releasing carbon dioxide, which can cause pressure buildup and rupture of closed containers. Elevated temperatures accelerate this process." My concern would be if you really sealed a hollow section, having the car heat up in the sun and potentially push out a panel. Of course, that's what you are trying to avoid by using the w/d version that has minimal expansion, compared to the gaps and cracks GS. Also, GS is about 20-30% isocyanate, and you don't want to be breathing the fumes while it is curing. I was very, very tempted to shoot GS into the A pillars and the sill. I haven't so far because of my concern that I might end up trapping water inside the car structure and helping it rust from the inside. For example, I have a sun roof. And there are all sorts of other ways that water can get inside structures. I wonder if the open pillars are part of drain paths. I may examine the sills and pillars more carefully from below to figure out how this really works. I think the idea of foaming these hollow areas is potentially excellent, both for structural rigidity and noise-reduction. The guys in Manilla were very enthusiastic after doing it!