Anyone ever use "Pillar Foam"?

[85 Cutlass Brougham]

I am considering the use of a special foam that is used in late model cars to add stiffness to the structure and reduce interior noise. I would put it in the hollow spaces of the B and C pillars and also around the perimeter of the roof inside the reinforcement. Has anyone ever done this before? My biggest concern is that it will expand too much and damage the exterior sheetmetal. My second biggest is the possibility of trapping moisture and causing rust. However, I have also heard that it keeps condensation moisture out of the metal and will help prevent rust as well. Any thoughts/experiences would be greatly appreciated before I do this.

 

[v8power]

i know a body shop guy that does something like that. all i know is you have to make sure there is no pockets in the foam, other wise that will hold moisture and rust. I am stopping by there tomorrow and will ask him what he uses for that.

 

[megaladon6]

if it is the same as the new car foam it does seal out moisture. i don't know if they make a spray, but PUR15 is a paint that you put on metal (including rusty metal) that completely prevents rust. that may help, especially on your floor pans.

 

[85 Cutlass Brougham]

Yeah, I need something I can put into the cavities I can't reach with paint and sanding, which is one of the reasons I want to use it. As for POR 15, I am using fiberglass resin instead because of cost. I have removed every speck of rust from the pans and they are very solid. I stand on them all of the time and have no issues. I am also using it to seal the underside of the car where I patched the pans so as to keep out moisture. I did a patch of fiberglass 3 or 4 years ago on the driver's floor and it is still rust-free. I can see through it and it is still shiny underneath it.

 

[megaladon6]

i just wanted to throw it ought there in case it would help.

 

[85 Cutlass Brougham]

Well, after talking to a friend who had this conversation with someone he knows who went through auto body school, I decided against it. It seems that it is a fire hazard and once it catches fire there is no way to put it out because of where it is. He said the new F-150's can't be welded because of it and that the foam in them can smolder for 20 hours and not even show itself until the truck erupts into flames! In a roof that has needed around 8 patches due to rust, I don't want to make it impossible to fix in the future, or make it harder to change the roof. So, I guess I'll stick with more traditional sound deadening and rust proofing and leave the flammable foam to Ford.