| to reinforce the sub-frame attachment on an e46; as they seem to be plagued with sub-frame tear outs. I know of one guy who has used it to reinforce the front sub-frame on a track e30. Once cured the foam has a compressive strength between 2000-3000 PSI. I had my doubts about it, but it is impressive stuff, almost like concrete when hardened, but very light. I had some leftover to mess around with and could not smash or crack it with a hammer after it cured. The foam can get expensive; I believe a 14oz cartridge is running about $80. If you are attempting to fill large areas a pneumatic gun is recommended which can get pricey too.
Loctite Henkel makes a lot of the stuff under the name Terocore. It is used my many manufactures to reinforce pillars to meet crash safety standards. Supposedly, structural foam repair/reinforcement has been used extensively for years in Europe (occasionally in the US) by bmw as an authorized dealer repair for mild cracks at the sub-frame attachment. According to the literature I checked out proper structural foams are not supposed to hold moisture. 
|
FWIW, I have used structural foam as a preventative measure - 
