Need paint blending advice (rust repair)

[02fanatic]

I have successfully repaired the rust hole on my '76 daily driver (well, in the summer anyway)....and I have put on two coats of one-step Dupont "Malaga" spray....color will be fairly close to the great paint job on the car overall.

I have two questions:

1. Should I always sand between coats?...and what grit?

2. What is the best way to "blend" the touch-up area into the surrounding paint on the fender? I have the repair area masked off with tape currently....I was thinkiing maybe I should remove the masking and sand the ridge where the tape was, then try to buff out overspray after applying one final coat.

Any help from you painters out there very much appreciated from this amateur body shop repairman! :-)

I guess that's several questions huh?

Thanks,

John

[esty]

it isn't necessary to sand between coats, assuming you're doing them all withinin the recoat window of the paint you're using...follow the specs on your brand of paint

blending is an art but the jest is to over reduce your final coat running onto the old paint...you'll want to knock down the paint line caused by the tape with 600 before the final coat

be careful over reduced paint tends to run

[02fanatic]

Is there some sort of buffing compound I can use once the paint dries after the final coat to buff out the overspray? I know body shops use the stuff....thanks for the tips. BTW, I am using 600 grit between coats, and I haven't had one bit of running problems (so far anyway).

[dubois]

First the repair area should be sanded with 600 wet or equivalent. The blend area should be sanded with 800 -1000. The masking should be a revese masking to avoid hard lines. The way to accomplish this is to cover the repaired area with 18" masking tape and simply lift the paper away, so the tape is covered by a nice roll. Obviously you have to tape the end so the paper won't fall back on the repair. Some lines have a chemical that helps the blended area stick, but a nice sanding should be able to do the job. The repaired area when dry will have a halo around it, where it was blended and some of the overspray. Here it comes the difficult part, especially on dark colors (such as malaga), one must make that dissapear by buffing lightly, hopefully it will feather nicely and will only be noticed from 3'. The trick is to buff from repair to blend, never the other way around. For inexperienced hands I would reccommend getting hold of some 3m extra cut compound and doing it by hand.

The easiest way if re repair is more than six square inches, is to clear the entire fender, and yes you can clear on top of single stage.

You can do it, the worst it could happen is that you may have to start over again.

No sanding between coats needed.

[02fanatic]

Well, I can only try...I'll follow up when finished to let you know how it goes. Thanks for the help!

[B-Doon]

I should know the answer to this as I used to be an auto claims adjuster...but are the 02's clear coated? I was thinking that an original paint job might be single stage only....then again, I have no idea if my paint job is original...I was going to do some rust repair and ask this question in the future, but now seems like a good time..

Brian

72 two tone inka/rust

[DukeRimmer]

Wash the entire fender with grease and wax remover. Lightly wet sand the entire fender with 1500 or some other ultra fine grit. Machine buff the entire fender, except repair area, with rubbing compound. Block sand the repair area with 400 until the mask line and any other flaws are removed. Block sand repair area with 600 to remove 400 grit scratches. Wash entire fender with grease and wax remover. Blow dust from gaps around fender and mask entire car, three feet of paper around fender and plastic beyond that (no need for plastic if using laquer). No masking on fender. Apply paint to the repair area. Use tack cloth to remove dust and dry overspray beween each coat. When the repair area is covered, reduce paint 50%, turn up air pressure, and recoat a larger area. Now reduce 100% and blend out farther. The size of the blend depends on the size of the repair. It takes practice to get the feel of the finer details. It has to look good on day one because the blend does not want to be buffed. It's just too thin. If the rest of the car is very bright and glossy, you can clear coat the entire fender after the blend. The clear can be color sanded, buffed, and polished as if you repainted the fender, but clear can cause a "color" mismatch if the door paint is not as glossy as clear coat. Good luck.

[Mike Self]

which is why they had so much trouble with their metallics--especially polaris and siennabraun. Clearcoat wasn't commonly used on production cars back in the 60s and early 70s...

mike

[DukeRimmer]

Metallics were clear coated, solids were not. Malaga is a solid, but clear will protect the color blend. When in doubt just drag a piece of black sand paper over it. Clear will transfer to the paper as white.

The failure you refer to is caused by oxidation of the color coat. When this happens the clear looses adhesion, cracks, and falls off. It's the americans that did not use clear in the sixties. Next time you see a dead paint job on a chevy notice it's a different failure. It looks like dead german paint after the clear has fallen away.