Minor Engine Bay Rust Treatment -Prepaint

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Robj

Robj

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I've got the engine out and am going to paint the engine bay. I've got a couple small areas of rust. The worst is under the washer bottle.

I'd like to get some thoughts on products you all use to treat it after cleaning it up but before paint. It's a daily driver/a couple small shows a year, not really a show car. I'd like it to look nice but is doesn't have to be perfect. I want the paint to stick and the rust to not be an issue in the future.

I'm not planning to strip all the paint in the engine bay. Some treatments look like they're pretty much for working on a piece that's completely bare metal with no paint. I'm looking for the products and the steps that can got over the scuffed up paint and bare metal and neutralize any small unseen pits of rust. It's been a long time since I've done this. There's so many new ones out there It would be nice to have some actual user knowledge.

Thanks

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That’s surface rust- basically nothing until it becomes something.

wire wheel clean, and coat it a good primer then body color. If not, steel wool it clean and try to not press too hard. Then clear over it. That will hold it back until you get the whole car painted.
 
I used POR once, didn’t stand up. Rerusted. The only way to remove rust for good is electrolysis that I know of.
 
I know basically squat about painting, so may have just been lucky but had rust on the firewall under the brake master cylinder. Can’t remember if I used sandpaper or a wire wheel but cleaned it up best I could and sprayed it with Rustoleum rust converter, primer then paint. That was 7-8 yrs ago, rust hasn’t come back
 
The body is good. We did that a few years ago. Just kept putting off the engine and the engine bay.

Rebuilding the engine now so it’s time.
 
Syleng1 said:
Electrolysis is for hair removal. Lol!
Click to expand...

youtube it, knocks all the rust clean off. I have done it several times.

the best muscle car restorers use it if they can get new or good used replacement metal. private metal treatment companies have tanks large enough to dip the whole car tilting it on the way in to remove all pockets of air in proprietary caustic solution. removes all rust, paint, body filler and seam sealer. there is one guy in Florida that goes after the seam sealer between spot welded sections with homemade knives and hooks to remove the trapped sealer. he even circles the areas that he cant get it out of.

the only sad thing about it is alot of cars come out looking like Swiss cheese, it removes rust in areas where you thought there was no rust.
it also harms no good metal unlike acid dipping or using stuff like vinegar or molasses.
 
I have had good luck with POR15, but I don't think that is what you want to use for mild surface rust. There are several brands of Rust Converter out there. The one I use is from TP Tools. You can get it from pretty much any car parts place and specially a car paint place. A lot of them contain Phosphoric Acid, so be careful. Anyway, the rust converter actually converts the chemical makeup of the rust and it turns black. It is no longer rust, it's chemical composition has changed. Any time I am dealing with minor surface rust like this, I always strip the panel to bare metal, and then treat the entire panel with the converter. That way, every little spot of rust gets treated. However, you said you did not want to strip the area to bare metal, so here is what I would do. Wire brush to get of as much loose rust as possible. Then sand the area with 220 and then 320 grit dry paper. Clean area thoroughly with some type of pre-paint solvent. NOT WITH WATER!. Then treat the entire area with the rust converter. Follow the directions for the brand you bought. When the appropriate time has elapsed, re-sand with 320 grit dry sandpaper, clean area thoroughly again with pre-paint solvent and apply a few coats of decent primer. You will have a lot of pock marks and scratches to fill in. Do that now with an easy to sand filler (a good spot filler would be best). Then final prime and paint. I know this sounds like a lot, but trust me when I say that there is no short cut to a nice looking repair that will include paint. Feel free to contact me via PM if you have any more questions.
 
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