Floor heat manifold boxes

[Twodose]

I was thinking about spraying great stuff in the manifold boxes outside, the metal is starting to rust pretty bad and thought that may be a way to keep any more dirt or moisture out of them, was wondering if anyone has done this, or if it would be a bad idea.

 

[OurTown]

Great Stuff is a good insulator but I think it is kind of a moisture sponge. It would not be fun to dig all that out if you had to fix a leak in there. What about spraying it with an oil made to slow rust? There are a bunch out there.

 

[MEP001]

Yes, Great Stuff does NOT keep out moisture.

 

[mjwalsh]

We have used in the past with good results to help protect rusted metal a similar spray such as the following:

Amazon.com: VHT SP229 Rust Convertor Can - 10.25 oz.: Automotive