car rust repair

Jim Wilkins · 2017-08-30T15:20:00+00:00

I have a persistent rust problem on the lower edges of rear fenders where the wheel well liner blocks access to the back side. The lower edge seam wasn't watertight and rust has perforated the outer and wheel well liner sheet metal below the factory sealer bead, which was applied from inside after spot-welding and didn't reach down to the joint. I dug out most of it so I could MIG weld patches without igniting it. Several local paint suppliers have suggested 3M 08852 Cavity Wax Plus to coat the inside of my larger welded and smaller resin patches to prevent or slow the so far yearly rust lines along their edges. LPS-3 wasn't up to the task, or I didn't coat the out-of-sight area well enough with it. The Cavity Wax comes with long applicator tubes. I'd like advice on if it really works, and how difficult it is to remove if for some reason it doesn't and I need to weld in a larger patch. The clerk told me it's better than rubberized undercoating in the wheel well. The suggested alternative there is spray can truck bedliner, assuming it can be removed if necessary. tia -jsw

car rust repair

Aug 30, 2017 23 Replies

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Bob Engelhardt 8 years ago

On 8/31/2017 5:20 PM, snipped-for-privacy@snyder.on.ca wrote: ...

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I'm late to the party, but I have some personal experience here. Back in '03 I painted a trailer frame with POR-15 and did not top coat it. (An erroneous page on their web site said that it didn't need to be top coated.)

The POR-15 that is on the part of the frame that is exposed is intact and there is no rusting there, or anywhere. It will likely fail sooner than if it was top coated, but I'm pretty satisfied with the 14 years that I've gotten.

Bob

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Jim Wilkins 8 years ago

I ended up brushing a similar Rust Converter into the gap between the fender and the wheel well edge, then sealing the openings in the highly curved area with SS heat treat foil stuck on with truck bed liner. Then I sprayed 3M Cavity Wax on the repair and the opposite side wheel well which didn't have the gap. Time will tell...

-jsw

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Larry Jaques 8 years ago

Did you tell them of this, and did they offer a quantity of top coat (or top coat and por15) to make up for the confusion? That would be cheap advertising and extremely good customer relations to do so for anyone who purchased product in that time frame, despite no known losses by the consumers. It would lock in consumer loyalty as well as begin free advertising by said consumers to future consumers. Just curious. At the price they're getting for the product, they can afford it, too.

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clare 8 years ago

POR15 followed by Black-Kote

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