Expanding foam to fill voids
I have been reading about using the cans of low expansion foam for sealing walls and subs from the trunk and what not.
Are there any problems with using it to fill places like the support frames in the roof and pillars?
I have read that they are toxic when burnt and that they could cause damage to the outer metal skin of the car.
When used sparingly can the cavities like the following picture be filled?

Will the heat effect it? (my truck is black) Will the roof expand and contract enough to effect anything?
Thanks for any info.
Later,
Brad
[ August 28, 2005, 10:27 AM: Message edited by: PistonHead ]
Are there any problems with using it to fill places like the support frames in the roof and pillars?
I have read that they are toxic when burnt and that they could cause damage to the outer metal skin of the car.
When used sparingly can the cavities like the following picture be filled?
Will the heat effect it? (my truck is black) Will the roof expand and contract enough to effect anything?
Thanks for any info.
Later,
Brad
[ August 28, 2005, 10:27 AM: Message edited by: PistonHead ]
Are there any problems with using it to fill places like the support frames in the roof and pillars?
I have read that they are toxic when burnt and that they could cause damage to the outer metal skin of the car.
Oh yeah they can damage the skin of the car if you select an aggressive expanding foam. Marine foams have a variety of densities and expansion rates, if it expands too slowly it will run out of the cavity if it is too aggressive you bend the sheet metal.
When used sparingly can the cavities like the following picture be filled?
i filled the cavities of my trunk lid with expanding foam.. i also have 3 layers of asphalt undercoating in my trunk and on the trunk lid, and 2 layers on the bottom of the spare tire well under the car.
ghetto yes, but it vibrates alot less than it did before. only thing i need is a deadener sheet for behind the license plate.
yeah its ghetto but it does the trick for now anyway, like john said though just be careful with the expansion rate of the foam you buy, because you can actually bend the metal if you put too much into too small a space
ghetto yes, but it vibrates alot less than it did before. only thing i need is a deadener sheet for behind the license plate.
yeah its ghetto but it does the trick for now anyway, like john said though just be careful with the expansion rate of the foam you buy, because you can actually bend the metal if you put too much into too small a space
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Very often, people use this and it causes ripples and undulations in the exterior body panels as it expands.
Another problem is that when being used in large quantities, it does always solidify in the middle. In the cavities you posted, it wouldn't likely experience this problem.
The flip side is, you aren't likely to hear any benefit from all your work - that area just isn't transmitting much sound into your vehicle. Use Brown Bread, Dynamat or B-Quiet and damp the flat panels.
If you were building some sort of high performance vehicle, then there are structural foams available that will fill cavities to increase the stiffness of the chassis and raise it's resonant frequency. You need to already be a 9/10ths before this would add any benefit - R-Compound tires, full suspension swap with all heim-joint / spherical links, etc... I cna dig up the name of that product if anyone needs it.
[ September 09, 2005, 06:52 AM: Message edited by: Dave_MacKinnon ]
Another problem is that when being used in large quantities, it does always solidify in the middle. In the cavities you posted, it wouldn't likely experience this problem.
The flip side is, you aren't likely to hear any benefit from all your work - that area just isn't transmitting much sound into your vehicle. Use Brown Bread, Dynamat or B-Quiet and damp the flat panels.
If you were building some sort of high performance vehicle, then there are structural foams available that will fill cavities to increase the stiffness of the chassis and raise it's resonant frequency. You need to already be a 9/10ths before this would add any benefit - R-Compound tires, full suspension swap with all heim-joint / spherical links, etc... I cna dig up the name of that product if anyone needs it.
[ September 09, 2005, 06:52 AM: Message edited by: Dave_MacKinnon ]
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