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· Registered
328 Posts
Discussion Starter · #1 ·
1. I inspected my ducts and found several areas where rust had made holes, so I removed all of them to inspect/clean/seal. I'm going to replace the sections with holes, but there were a few small areas where rust had started, but it's only on one side. Is there something I can put on those spots to stop it from rusting further, instead of replacing the section? This is the worst one... it seems to be from insulation sticking to the duct, in this case.


2. The insulation is old (30+ years), but it's still mostly intact. I plan on re-using most of it, unless there is a particular reason not to. Most is an unlabeled faced yellow fiberglass.


3. None of the ducts were sealed, so I'm going to seal all seams/joints with mastic (no tape, unless there is a reason to use it)... is there a preferred order of doing this? I would like to seal them and insulate outside of the crawl space, but I'm afraid the mastic might get disturbed during installation. If so, I'll just install and add mastic/insulation after.


· Hvac Pro
25,111 Posts
I would take a wire brush and clean off the rust and then wrap the area with silver foil tape. HDepot has it. You can seal all the other joints with it also. It is not terribly expensive.

Or order a large roll online from Amazon or elsewhere.
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