expanding foam inside body cavities?

yeah he beat me to it....if you use the right material( ie duramix) it is designed to work in that environment, I would not use mono foam or any harware type deal.....and do not fill the cavity up, that is what will cause warpage, do i in 3 or 4 small steps and it should be fine.....but do a test peice first.

And dynamat is overpriced, brown bread or other similar products are as good but cheaper.
http://www.b-quiet.com/brownbread.html
http://www.zeronoise.com/prod01.htm" target="_blank" rel="nofollow">http://www.zeronoise.com/prod01.htm
http://www.zeronoise.com/prod01.htm" target="_blank" rel="nofollow">http://www.zeronoise.com/prod01.htm

thanks guys. yeah, like for pillars and areas that arent able to be gotten to, i was going to use a hole saw to cut out like 3/4" holes. fill the areas. then when its done, id fill them back in. how much would that stuff run? and how much does each amount (gallon, pint, whatever) cover? if nothing else, id like to use it inside the bedsides.

I KNOW WINDOW COMPANIES WILL VOID WARANTIES ON HOUSE WINDOWS IF YOU PUT THE FOAM IN THE CRACKS BESIDE THE WINDOW BECAUSE IT EXPANDS SO MUCH THAT IT DISTORTS THE WINDOW FRAME CAUSING THE WINDOW NOT TO GO UP AND DOWN.JUST THINK WHAT IT COULD DO TO SOME THIN UNSUPPORTED SHEETMETAL.

If you use 2 part foam and leave one side completly open it will work. but pouring somewhere that has a part open and part blocked it will force the block side to push againts the metal. it works good if you have the right circumstances to do it.