Wet Sand Paint Runs?

[royalkangaroo]

I've got a 2010 Silverado that has some paint runs from the previous owner's attempted touch up. The color matches perfectly, and honestly you can't see it unless you know it's there. However, it does have some noticeable runs and a non-smooth texture. Therefore I was wondering if I could wet sand it to smooth it out. I have a GG6 DA polisher at my disposal, but there's many opinions whether they are sufficient for wet sanding.

Any thoughts? Is this something I can improve or better off leaving alone?

Tried to take some pictures as shown below.

 

[builthatch]

a GG6 is more than enough to do whatever you need to do. don't doubt it!

yeah, you can block those runs down, wet sand the whole damn thing and compound/polish accordingly. the GG6 can do the sanding mark removal, compounding and polishing.

 

[RedXray]

I'd start with 1500 and a rubber block to eliminating the sags then working my way up to a P3000 Trizact pad. The GG polisher with an orange cutting pad will remove the P3000 sanding marks then move to a white or gray finishing pad.

I shot this bumper with PPG Deltron and finished with this same method. (Griots 6" RO polisher)

 

[builthatch]

I'd start with 1500 and a rubber block to eliminating the sags then working my way up to a P3000 Trizact pad. The GG polisher with an orange cutting pad will remove the P3000 sanding marks then move to a white or gray finishing pad.

I shot this bumper with PPG Deltron and finished with this same method. (Griots 6" RO polisher)

ha, i meant to ask you this the other day after seeing another post. your user name reminded me - have you ever used red lead? lol

 

[Mantilgh]

Would it be a good idea to tape off first around the area and wet sand down to the tape?

That way you would reduce the amount of clear, or paint, that you remove from the unaffected area and would only be sanding on the run. Then pull the tape and continue with your sanding to completely level...?

 

[RedXray]

Would it be a good idea to tape off first around the area and wet sand down to the tape?

That way you would reduce the amount of clear, or paint, that you remove from the unaffected area and would only be sanding on the run. Then pull the tape and continue with your sanding to completely level...?

In theory yes...

BUT

You/we don't know how well that repair has been prepped. Pull tape and you run the chance of pulling the paint off with the tape. The rubber block will only cut the high spots giving your eyes a way to map the cut as the sags disappear.

 

[Mantilgh]

In theory yes...

BUT

You/we don't know how well that repair has been prepped. Pull tape and you run the chance of pulling the paint off with the tape.

I see what you are saying. I was thinking of something like a scratch repair with a run.

The rubber block will only cut the high spots giving your eyes a way to map the cut as the sags disappear.

Yes, if you do it carefully and keep the block only on top of the run. Chances are you are going to hit areas you don't want to with the folded fresh corner of the block. You will also need to remove that, or those cuts, removing more clear, or paint. Not much, but some.

 

[royalkangaroo]

Couple more bits of information, I've owned the truck for 2 1/2 years or so, not sure if that factors in to the touch up paints hardness, etc. And the overall irregular area is about the size of your palm with the paint runs limited to a smaller section. (Also not sure what they did to have them streaking horizontal)

 

[RedXray]

I see what you are saying. I was thinking of something like a scratch repair with a run.



Yes, if you do it carefully and keep the block only on top of the run. Chances are you are going to hit areas you don't want to with the folded fresh corner of the block. You will also need to remove that, or those cuts, removing more clear, or paint. Not much, but some.

True but the block can be anything as small as a rubber squeegee doing fineness type sanding if one is that paranoid. Just be smart and don't go ape crazy you'll be fine.

The best practice is not to have any sags in the first place.

Shooting cars over 40 years... I've pulled runs off (first & second coats) with long pieces of 3/4" masking tape as they're still wet & running, touch the run with the tape pulling back, then flow the oops mark out with subsequent wet coats. I've used razor blades shaving off dried runs holding the blade angled away from the sag (this cuts down on wet sanding time). Painting cars you hate to see them but you learn to deal/repair them.

Wet = Shine

I'd rather see someone learning to paint have a few repairable runs in the finish, than someone that was to gun shy of runs and didn't get the panels wet. Dry shot paint will never shine, at least with a run or two the painter got it wet.

 

[RedXray]

Couple more bits of information, I've owned the truck for 2 1/2 years or so, not sure if that factors in to the touch up paints hardness, etc. And the overall irregular area is about the size of your palm with the paint runs limited to a smaller section. (Also not sure what they did to have them streaking horizontal)

I'd recommend wet sanding using a rubber block with 3M 1500 wetordry to eliminate the sags. Follow with 3M 2000, then with a 3M Trizact P3000 sanding pad. Then follow with the GG6"

ETA: if the 1500 doesn't cut drop down to 1000

You can find the Trizact at Autozone It's not paper but a rubber like pad... like this.

 

[royalkangaroo]

Awesome, thanks for the tips. I'll give it a try soon and post the results.

 

[Mike@DedicatedPerfection]

Instead of wrapping a piece of sandpaper around a "block", use an actual sanding block such as the ones offered from Meguiar's. Not only will they be much easier to handle, the will often give better results as the sanding tool will be comprised of a single piece rather than two combined together.
http://www.autogeekonline.net/forum...meguiar-s-unigrit-sanding-block-k-1000-a.html

Then you can pick up your machine and properly finish off the task at hand.

 

[royalkangaroo]

Are there potential problems if we don't know how the touchup was done?

Correct me if I'm wrong, however in order to level out runs, you're sanding the paint layer smooth. I'm honestly not sure if there was a clear coat put over this spot or not. Is this an issue?

 

[RedXray]

Are there potential problems if we don't know how the touchup was done?

Correct me if I'm wrong, however in order to level out runs, you're sanding the paint layer smooth. I'm honestly not sure if there was a clear coat put over this spot or not. Is this an issue?

Yes it very well could be an issue being it's a metallic finish. Without a clear coat it's possible to sand into the touch up and fracture the metallic flakes causing a darker area (line). The oem finish won't be affected only the repair. If this happens you'd simply brush on more of the base color then top coat with clear, then repeat the sanding/polishing process.

The paint that's on the scratch even though fractured is still doing it's job of filling the low area of the scratch. You'll know as soon as the wet paper hits the repair if it's cleared. Clear residue will look white watered down milky like whereas the silver base coat will show the color and metallic in the residue.

 

[royalkangaroo]

Yes it very well could be an issue being it's a metallic finish. Without a clear coat it's possible to sand into the touch up and fracture the metallic flakes causing a darker area (line). The oem finish won't be affected only the repair. If this happens you'd simply brush on more of the base color then top coat with clear, then repeat the sanding/polishing process.

The paint that's on the scratch even though fractured is still doing it's job of filling the low area of the scratch. You'll know as soon as the wet paper hits the repair if it's cleared. Clear residue will look white watered down milky like whereas the silver base coat will show the color and metallic in the residue.

I guess my question would be what's the proper protocol. By the looks of it, there's a small dent which probably entailed a decent scuff which led the previous owner to just spray touchup paint over it.

Therefore would you use sanding blocks to level/remove the touchup down to the oem clearcoat (certainly the scuffs would still be filled), then seal/wax it?

 

[RedXray]

After taking another look at the photos...

If you take the repair down to the oem your opening a can of worms a non painter may wish he left alone. The problem is you don't know whats under the repair. It may have plastic filler and primer underneath.

My advice is if your going to try to make it look better is to carefully block on one of the sags and see how easy it cuts and if it's clear coated. You'll probably want to continue if you're cutting clear. If not I'd say to stop and have it re-sprayed or just live with it. The re-spray will be a color blend at the repair area and the complete panel clear coated.