Okay, so I get the fenders and other rusted parts sandblaster and then I have these pits left behind. Not deep ones but there none the less and now I need to know how to take care of these. Years ago I used a red oxide paste to cover minor blemishes but like I said that was 25 years ago. What should I do to fill these minor pits to prepare for paint? Pic of fender before and after sandblasting with primer.
Can't really tell from the pic but it looks like no big deal. If it's deeper than it looks in the pic just skim it with body filler, knock it down with a flat sander and shoot it with primer. If it's light, a high build primer will get the job done. Ask your paint supplier... -Ron
As long as the blasting got all the rust out of the pits, apply two coats of high build primer and sand it out. If you liked red oxide, you will love high build. Eastwood sells, Featherfill and Slicksand...check them out.
as long as there isnt rust in the pits (redish brown) just skim over it with filler. if there is still rust in the pits either take it back and have it shot again or spot blast it your self or use a chemical to neutralize it, so your paint doesn't bubble up down the road. most likely the pits are just what the rust ate and what you have is whats left of the good metal.
Good point Kail, I was told to cover it with naval jelly first then wipe it down. He said it would neutralize the rust so it doesnt reappear. That true and if so how do you you apply it the right way? ie. wipe it on and wash off before blasting or after blasting?
If there is still rust in the pits, then it wasn't properly blasted and needs to be redone. Cover it in naval jelly? That's the worst advice I've ever heard. Why not just spray WD40 all over it and guarantee that you'll never get paint to stick.
If your worried about rust coming back. Metal prep first.then Half time or icing Prime first,,,,, Quality glazing putties Also fiberglass doesnt stick to metal. Expands and contracts at different rates. Instead of naval jelly Id even consider Jb weld. Im toying with it on my car. Dont know if it hold Only did shifter handle Coated over jb weld And im gonna try it on trans tunnel. Any of my advise is old school Just dont use nitro-stain Only good for scratches,Using laquer based primers .The reason why cars cracked is they used nitro stain as filler and after 13 or more coats of laquer Everything loosened up, Also never use spray can primer its Inferior to any automotive paint. another words paint problems.....
is this pitting something I could/should treat with heavier sanding? Then come back over it with lighter sanding until pitting is gone? Or not a good idea.
da w/80 grit then use a metal cleaner like dx579 from ppg. then epoxy prime, from there it's on with body filler or slicksand whichever you choose.
Really dont think the fiberglass filler would stick huh? Kinda what its designed for. Never had a problem with it. Id use that, or metal to metal filler, something along those lines. After the filling process, prime it with an epoxy based primer. Prime with normal shit and go thru the normal process. And to the comment of the f/g filler not sticking well, polyester filler if put on properly doesnt come off. And it expands and contracts at different rates. The sandblasting pits are enough for the epoxy to stick to. Just dont use an etch on the blasted metal, it falls into the pits and doesnt stay on top from what im told from my PPG instructor.
if its just pitted don't over think it just level with filler (bondo) and thats it, the rust should be gone, and i wouldnt grind the metal smooth because then its going to be even thinner which can lead to trouble.
Im not sure if featherfill has any etching properties. Its a polyester based primer, basically you are spraying a "skim coat of filler" onto the panel. Look into it and see if it does any etching properties or a high zinc content. Or just spray epoxy down, but the featherfill is a good idea. Forgot all about that one. Probably wont work on nasty pits tho. Mite be a good option though.
This is getting really confusing to follow. If there's rust in the pits, have it re-blasted or use Picklex 20. Its a spray that works great to rid rust from deep pits. Let it sit for a minute and wire brush the snot out of it. Done. Then either filler if its really deep, or a high build primer thats good for bare metal. Read the tech sheets to see if the primer is OK to go over bare metal. Etching primers usually arent going to offer a good build sufficient ebough to fill pits and high-build urethanes that are ok for bare metal are very high priced. I use HOK KP2 Epoxy primer for this very task. I Picklex the rusty pits and then a round of epoxy primer and/or filler.
Old school here. Here's a trick most body men never learned. You need 4 things, then paint. First, Take a propane torch and flash the moisture off the metal. You will actually see it run ahead of the flame. Next use a product called "Ospho" It's an acid that turns rust back into iron. I stripped a roof on a 57 chevy while living in Orlando Fla. I coated the whole roof with a throw away paint brush. I left it outside for 4 days and it never did rust even with the dew and humidity. I swear by it. If you need to fill some holes, I've found that "Aluma lead" or "All metal" works great. Warning. It gets burning hot in a hurry, so work quick. A heavy fill red oxicde primer will fill the small pinholes, water sand with 220 then use "Egal claw" spot filler if needed. Let dry, water sand again, light coat of primer, water sand with 600, then lay the paint to it. Guarenteed it will never rust under the paint. I learned this from a professional named Butch Scarlatta from Classic auto body. His waiting list was over 3 years. I don't use air tools. I can do a faster job with paper wrapped around a paint stick. You don't get sea sick looking down a side of my car.
All sounds pretty cool except the red oxide primer man...it is old school and should probably be left there. Sorry. Much superior products to it now.
Grampa always swore by the brush, claimed it worked the paint into the metal instead of it laying on top. seems to be true. I've often primered up with a brush. works good and not too hard to sand out the brush strokes. If thats too fancy get some red tractor paint and put it on with a broom nice and thick
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