Spray Foam behind chair rail

[cilantro]

Hi all,

I'm still in the demolition/deconstruction process. My bus is 7 windows in length, and behind the chair rail of the back 4 windows on each side there is cured spray foam. Its dirty, its damp, its gross, and I want it gone. Does anyone have any good suggestions to scoop it out?

I was able to do the smaller pocket above the wheel well using a scraper and the back end of a hammer to "scoop" it out but this is a lot of effort. Small bits I can get out with a shop vac. Any ideas for tools/techniques to break it up and get it out?

Thank you friends!

[musigenesis]

Gasoline or some other kind of solvent would probably work. Last year one of my gas cans fell over in the back while driving and a tiny bit of gas leaked out, and it ate away a surprisingly large amount of the XPS foam board of my subfloor. You would of course want to be very careful doing this. Eventually all the gas or solvent will evaporate, although it would be smelly for a little bit.

Personally I would just leave it as it is, too much work to remove it with really no benefit.

[cilantro]

Originally Posted by musigenesis

Gasoline or some other kind of solvent would probably work. Last year one of my gas cans fell over in the back while driving and a tiny bit of gas leaked out, and it ate away a surprisingly large amount of the XPS foam board of my subfloor. You would of course want to be very careful doing this. Eventually all the gas or solvent will evaporate, although it would be smelly for a little bit.

Personally I would just leave it as it is, too much work to remove it with really no benefit.

I've considered leaving it as-is. The only real reason for me would be to treat any surface rust that is living in there. If it wasn't for the rust I wouldn't consider this.

[musigenesis]

Originally Posted by cilantro

I've considered leaving it as-is. The only real reason for me would be to treat any surface rust that is living in there. If it wasn't for the rust I wouldn't consider this.

If it's that stuff from a can (which it probably is) then possibly you do have some rust behind there - rust that was caused by the stuff in the can. That foam is single-component which means it requires air to cure properly; without the proper curing it stays wet for a long time and can cause corrosion. The chair rail is made of galvanized steel, though, so in all likelihood it's fine.

[BeNimble]

If its spray foam, no chemical will effect it. What I use is a vibrating tool, and scrape it off. Great tool, second only to the angle grinder.

[Danjo]

I like the don’t worry about it solution. If you have leaks, worry about that instead. The foam will dry out eventually

[o1marc]

Quick Google search says scraping and sanding to remove cured foam. Whether it was closed cell or open cell depends on what the water is doing with it. Open cell will hold water.

[Oscar1]

Break a piece off, if it’s only damp on the outside and dry crumbly inside it’s likely closed cell. If it’s open cell foam it will retain that moisture and more even if you fix the leaks. If it’s closed cell leave it, the surface will dry if not subjected to more water. Unknown rust in there, yes a good chance of that especially coming from Ontario. Without removing the exterior skin you’d likely never get enough out to deal with rust remediation anyway and it would be a massive amount of work. Confirm it’s closed cell and fix the leaks, if it’s open cell foam sell the bus. Just my opinion.
PS say hi to my sister for me, she’s in Milton. Lol
Cheers

Oscar