DuB

iTrader: (1)

For those of you who have cut your fenders, what did you use to seal the edge to protect from rust? Mine is currently painted, but I'm hoping there's something more gummy or tougher.

is150

iTrader: (10)

I primed the exposed cut and top coated with an underbody spray. The underbody spray I used hardened and wasn't rubberized.

thekhmer

iTrader: (2)

3m seam sealer

veez81

I’ve gone over it with waterproof silicon

DuB

iTrader: (1)

Hmm, all good ideas. Anyone have experience with POR-15?

kietlander

Any reason to cut instead of roll?

mkmckinley

If you cut through the factory paint and coating it will eventually rust no matter what you paint it with.

DuB

iTrader: (1)

If you seal any exposed metal, it won't be able to oxidize/rust. I don't understand the significance of if it's factory or aftermarket coating.

bclexus

At the factory car bodies are protected with special chemical formulations, typically phosphate conversion coatings where the car body is dipped into large heated tanks. Some car makers galvanize part or all of their car bodies before the rust inhibiting primer coat of paint is applied. If you cut, scrape or scratch the rust preventative protection (be it phosphate coating, galvanizing or specialized rust inhibiting primer) you expose the sheet metal to rusting. Sealing is usually the application of an aftermarket coating onto the surface of the sheet metal. Unless the sheet metal, which has been cut, scraped or scratched, has been properly cleaned and treated before the aftermarket sealing product is applied, whatever protection it may offer will be minimal at best.

DuB

iTrader: (1)

Yeah, I plan on cleaning the metal properly prior to sealing it again. "It eventually rust no matter what you paint it with" is a bit strong of a statement though.

I live in CA so I prob don't have to worry much, but I was wondering what you guys in the wetter areas use? It wouldn't hurt me to be safer than sorry. Plus it'd be good reference for anyone doing a forum search later on.

mkmckinley

You're not going to be able to re-plate the part and you can't get the same adhesion that the factory paint job achieved. The factory finish starts with plating/galvanization and then goes to seamless heat cured paint that covers the whole surface. It doesn't matter how careful you are cleaning the bare metal. Whatever room temperature curing paint you use will have microscopic pores and cracks that will allow the base metal to be exposed to oxygen. You'll also always have an overlap between whatever paint you put on and the factory paint. This is true especially in the area you're describing where there's a lot of flexing, heat cycling, impact from road grit, vibration etc. Eventually you're gonna have rust.

It's your car, I genuinely do not care what you do with it. I was just trying to answer your original question.