I'm a little torn on what to paint the outside of the wheelhouse with.. I have bare metal exposed from sandblasting and welding. The metal is not rusty so I am not sure I should put rust encapsulator on it. Does the eastwood stuff stick to clean metal better than POR-15? I could use cold galvanizing compound, which should prevent rust but can't be painted over (not a big deal there). Or, I could prime and paint it with spray bomb paint. Assuming I get everything sealed up like I should, does it really matter what I use? I have to spray the wheelhouse before I weld the quarter panel on because I can't get to it after that. The inside of the quarter I can do before or after I weld it on, I may do it before so it's easier to get to. So, I need to know soon.
The rust encapsulators (I speak mainly from experience with POR-15) do not stick well to clean metal. I would spray a little water on it from a spray bottle, let it sit a couple days and get a nice layer of "dusty" rust. Brush the rust off and paint the POR-15 right on it. The thin layer of rust actually etches the metal so the POR-15 sticks to it. That should take care of you for life. If you want to paint over it, I think you can hit the POR-15 with 400grit wet sand paper and paint over it, although I have never done it. I like the powdercoated look that dry POR-15 has. Side note--I had a spot rust through the paint on my truck about 2 years ago and figured that since it was exposed to sunlight, I would use it as a test for POR-15 in the elements. I heard it turns gray when exposed to sunlight.... Well, it has kept the rust from coming back all this time. It has lost some of it's glossiness, but continues to do it's job. I might try to rough it up and paint over it one of these days... Damn, this response ended up being pretty long winded...
on the unexposed areas i always use cold galvanizing compound to seal them. i haven't tried the por-15 so i can't speak to that end but the galvanizing works well.
It's a zinc-rich coating (looks like primer, but paint don't stick to it that well). I have a spray can of it from Eastwood (hmm, did I buy a quart can too?), and I was kinda leaning toward using it, just wanted to hear others ideas, since it's been so long since I bought it, I don't remember what I planned to use it for.
Por 15 makes a product called "Metal Ready" it will etch bare metal to help the Por 15 stick, I've used it everyware I can on my car.
When I had new rear quarters installed about 11 years ago the body shop coated my wheel wells with roofing tar. The guy said he's "been doing this since the 50s, and if the stuff lasts 20 years on a roof think how long it'll last on your car". It has held up great for 11 years so far.
