Cleaning walls for spray foam

[Crisfole]

How clean should my walls be for good spray foam adhesion? Getting this stuff off is _really_ hard...
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[EastCoastCB]

Links aren't working.

[Crisfole]

Posted from Tapatalk.... One sec

[Crisfole]

Ok, I'll describe... Weird that the links work for me. Anyway:

The entire inter wall is covered in old adhesive and composite strips of wood used to keep buzzing down, I presume. It's all 35+ years old and very hard to get off...

[TJones]

Originally Posted by Crisfole

Ok, I'll describe... Weird that the links work for me. Anyway:

The entire inter wall is covered in old adhesive and composite strips of wood used to keep buzzing down, I presume. It's all 35+ years old and very hard to get off...

If its dry and not sticky or oily it should stick ok. You could get a cheap can of great stuff and do a test area. With a bus of that age you want to make sure the metal is not corroding behind the adhesive. I had lots of sticky black goo that I wasn't confident spray foam would stick to so I've removed it. It was a huge PITA but I know my spray foam will stick now.

Ted

[o1marc]

That foam pretty much sticks to everything. It sticks even better to everything you don't want it on.

[Crisfole]

Haha! The whole bus is Aluminum except one or two parts. Aluminum oxide isn't that damaging or spreading, happily!

I'll probably just chisel it off then wire brush it.