rwd

I'm looking to touch up a 1/2 inch elliptical mark where the clearcoat on a fender edge has apparently been worn through.

Inside and outside the mark, the color is fine, but I'm not sure how to make the ellipse itself disappear.

More clearcoat doesn't seem to hide it, and although clearcoat can be polished to eliminate scratches, that doesn't seem to work on this. Similarly, if the mark were discolored/burned clearcoat, I would have thought it could be removed by going further down to the color, but that doesn't seem to work, either, although I haven't been too aggressive with it.

If anybody has a solution, I'd certainly like to hear it.

Spraygun

Hi, that is a tricky repair, I've pulled it off a couple times, but it's hairy..
How I did it:
I degreased area, lightly sanded with 800 dry for a couple inches around the damage, then use rubbing compound to prep area 24 inches around where you sanded, then degrease again. Lightly spot in with basecoat ( if it's metallic you should do spray out panels till you get the right pressure/fluid nozzle adjustment to match car) When i do the base I'll back tape the paper ( put paper about 10 inches outside repair with paper covering repair area then pull the paper back over itself to leave a roll so any overspray will not be a hard line) dust your base till your satisfied, then pull paper ( do not tack, the basecoat dust around repair area will act as a blend ) repaper in the same manner about 12 to 15 inches out depending on how the base looks. Mix clear thin, add extra reducer to allow you to dust clear on and have it shine. first coat just over base, let flash, the next coat out over basecoat dust into unsanded finish. Now this is where it gets tricky, you need to melt the clear edge, depending on what paint line you are using there may be a product for this, PPG has DX840. If not mix your ready to spray clear with 4 to 5 times by volume with a med or slow reducer. Pull the paper and spray the edge of the clear with your blender, lightly at first watching how it's working. Take your time, be sure to let blender flash before applying more, it's easy to run the thin blending solution.At this point your repair may look ugly, don't fret, if you have a hazy area around your repair with no clear edge visible your in good shape. let dry overnight and buff area with a light compound you'll cut the haze back toward the repair, you should be able to have a very light line or no line cut back to the area of unsanded clear around your repair. Let it sit for a couple hours after compounding, the buff wth glaze, the use hand glaze. let sit overnight. ( if your repair has to be done at this time, wax the area with a paste wax, if you did your repair properly you should see no evidence of your repair. If you have time let the repair sit for a coupe days giving the clear time to cure before waxing )
Good luck, I found it nerve racking, usually having to repair a mistake on one of my jobs done by bodyman during reassembly. i hope it works out for you.

rwd

Many thanks for the comprehensive and detailed post. I can see how it would work.

Just out of curiousity, do you know why the actual clearcoat damage (whatever that visible mark or edge between the undamaged basecoat and undamaged clearcoat is) can't either be just rubbed off down to the basecoat leaving undamaged basecoat and clearcoat with no visible line- or if that's not possible, polished out to the point that it's shiny like the remaining good clearcoat (as you might with a scratch or mark on clearcoat).

It seems as though if you try to polish or buff the ellipse out, it just makes the ellipse edge larger.

Spraygun

The line is where the layer of clear is missing, when you spray clear over base, it bites into the base but does not mix with it to become one layer. If you polish the base it won't shine well and will dull quickly as it has no UV protection without clear on top

rwd

Thanks, again, Spraygun.

If I'm following you, the small, dull ellipse is really the only area where the clearcoat is burned through. The shiny paint inside and outside the ring are where the clearcoat is still intact.

I couldn't get much of a shine polishing the ellipse (base, presumably) prior to putting some clear over it, and when I put some clear over it the ring showed through. It appears gray, so I had thought perhaps it might be a damaged area that could be polished out or polished off, but that doesn't seem to be the case.

I'm toying with trying to put some thinned touch-up paint over the ellipse to get solid color to work with, and then, if necessary, some clear over it. It's difficult because of the small size and working with a touch-up brush.

Would an airbrush be a viable alternative for applying the paint, and, if so, could you suggest one? I have no experience with this, and JSB isn't much fun to work with. The area is going to be covered with protectant and clear film once the repair is done to prevent further damage, but right now the damage will show through the film. If I can get a reasonably smooth solid color, that shouldn't be the case.

I appreciate your patience. I have very little experience with this.

Edited to add: fwiw, the damage is mostly on a vertical surface of a ^ sail panel. It just touches the top of the ^ break, and that's where the ellipse burned through. I'm trying to get a solid color and a continuous edge.

Spraygun

Without seeing it, I really can't say. No matter which type of burn it is, you have to cover the affected area with base coat to hide the problem, then clear. If it is a deep burn you may need to level the area with a small block. You can use an airbrush, touch uo gun, etc the important thing is to be comfortable and profiecent with what ever you use.

rwd

Understood.

The surface is probably level enough on both the original and collateral damage.

The collateral edge burn occurred after polishing repeated attempts to get a touch-up paint color that matched (still a problem) and then make the edge contour continuous.

Given the small area involved (less than an inch square) and that little additional paint depth is needed or desirable, an airbrush would probably be best suited, but I don't have the tools or the experience, so I'll try to brush a small amount of color over the burn and go from there.

Perhaps thinning the paint slightly will reduce the amount added and minimize the resultant polishing/smoothing required so that more edge burn doesn't occur while trying to match the contour.

Thanks for the help and follow-up.

Spraygun

I've never had much luck using a brush, I bought an airbrush and hose for under 40 bucks and use the aerosal propellant for super small areas inside corners or other problem spots. I mostly use a full size spraygun or a touch up gun throttled back for such repairs. If your anywhere near Maryland, I'd be happy to come out and give you a hand.

G

rwd

Sadly, I don't leave anywhere near Maryland, but as a result of your offer of help, I'm thinking of moving.

As mentioned, the damaged area is quite small, and the ellipse itself is little more than 9/16" x 1/8". The shop manager I've been talking with thinks it's probably too small to airbrush and that a very thin application by brush may be the best way. I've gotten some decent brushes, and that's helped.

The problem, really, is the paint. Since the ellipse is on a sharp panel edge it catches all the light, and, in addition to the metalflake, the paint has that obnoxious purple/green ChromaFlair, or whatever it's called, color shift component.

It may be suited for spraying en masse, but, apparently, not for brushing. It tends to streak and glob up, and, worse, it's just not possible to predict how it will match the car until it's in place. I've had work that was otherwise acceptable wrecked because the paint hue shifted slightly to purple or green and stood out like a neon sign against the car's blue. [The repeated work is what caused the burn through.]

The only solution I can think of is just to keep brushing a tiny amount on, and if it doesn't match take it off and try again.

That leaves two questions. One, I was told the GM touch-up paint has clearcoat mixed in. Should it be necessary to put a separate clearcoat layer over it, or will it shine acceptably once it's completely dry, polished and waxed? Two, how long do I need to let the coat dry before I work on it again. I've seen times as long as a week.

I appreciate the assistance, and I'll try pretty much anything at this point.