Hey Guys,

I painted my Chevelle yesterday, and ended up with on sag in the Urethane (single stage). I could not get Base coat - clear coat at my local paint shop. Anyway, I have one sag, how do I go about sanding it out. Do I wait for two days, then use 400 and then 800 grit sandpaper? Or do I wait a longer period of time and use a different grit sandpaper? Any help would be greatly appreciated.

Thanks,
Fred.

You didn't say if the paint is metallic or not. If it is, perhaps you already know that you will have to repaint that panel. A solid color could be sanded out and polished now.

No bc/cc at your local paint store?? Sheesh, that's like a Ford dealer only having Edsels to sell today.

And with 1500-2k grit paper, anything courser scratches probably won't come out.

Boy, this would take a lot longer than I have this morning but don't think that you "simply" sand it out and polish. The critical part and I do mean critical is that you ONLY sand the run and not the surrounding area! This is much easier said than done. The run is MUCH thicker than the surrounding area right? Well, let's say that it would take 10 passes with the paper to cut thru the paint where there is no run. And it is going to take 50 or 60 passes to cut flatten the run. These are just out of my head of course it is not what you will do but bare with me. While you are sanding your 50 to 60 passes over the run if you simply "hit" the surrounding area a lousy 10 times you are going thru, get it?

It is VERY. VERY easy to sand thru the paint next to a run. So you have to use some small block (many painters use a little piece of a wood mixing stick) I have a regular 3x5 rubber block that I have cut with a hack saw that is now two blocks of 1x5 and 2x5. The little one works well for this. You just need to REALLY concentrate the sanding ON the run ALONE.

Depending on where it is using 600 or even 400 "can" work because you sand ONLY the run and long before it is flat with the surrounding paint, you have switched to 1000, 1200,1500, and 2000 so polishing out the 400 or 600 scratches is not an issue.

I have to say that I have not learned the technique being I am not painting everyday, these days. But our polishing guy at work takes runs out by "scraping" a razor blade over the run. He is absolutely amazing! He will hardly need sand paper when he is done! He takes runs out of tiny spots like body lines or door handle pockets. Places that I would have simply sanded and reshot, this guy REALLY knows his stuff when it comes to "making it shine". ;)

Hey Guys,

Thanks a lot, I'm going to give it a try. The paint is not a metallic, so I have a chance. I like the razor blade idea, that makes a lot of sense, especially in this case. I was told that you need to make sure that it is hardend. When you can't press you thumbnail into it, it's ready. I'll let you know how it works out. Heck, worst case, I reshoot the panel.

Thanks,
Fred.

Not that it helps now but Eastwoods sells a razor blade tool for this problem. Looks like a tiny wood plane.

Dave, that is not the same way I am refering to. The Eastwood tool looks like a "plane" as you say and "shaves" the run. Don't like it, I have one, don't like it. The method I am refering to that the guy at work uses is a single edge razor in two fingers and sort of "waving" the thing over the run barely touching it. It "scrapes" a tiny amount off with each "wave". I have not tried at all to do it, but you have me thinking. I really need to go over and have him teach me.

Razor trick works, but hold on before having a go at it, knock the corners off the blade, avoids digging the sharp corners into the panel.
I also take a new blade and take a pass on a file to dull it slightly. Old timer showed me and it works.

The Razor blade shaver is an old tired and true
technique... You use a new blade.. hold it with your two hand and bend it's back bone...
You want to drag it not push it over the sag.
you'll see the shaving off the high point of the hanger-sag..as you drag it along the ridge..
As MartinSR pointed out.. you have to be carfull because the area ABOVE the run/hanger/sag is thin ...
Take your time shaving it down, keep draging the high spot you'll see it widen out as you start knocking it down...

Very Good Wayne and Jim, you explained things well.

"Take your time shaving it down, keep draging the high spot you'll see it widen out as you start knocking it down..."

VERY good way to discribe that Wayne. I am going to get with our guy at work and have him show me that technique. I see him do things with it that are just amazing as I said. I would like to work with him a few days I'll tell you that. He is the best I have ever seen at cutting and buffing. When we cut and buff a car at work it is usually before it is put together. No mouldings, windshield washer squirters on the hood, no handles, so it is easy to cut and buff. This guy doesn't even car if it is put together. I know I want them apart to make it easier and every buffing guy I have ever worked with does too. Gabino (our buffers name) doesn't care. Give it to him assembled and he will sand and buff it just as fast. He is very very good.

Would you expect this technique to work with other imperfections, such as small specs of dust in the clear? I occasionally paint and try to be as clean as possible, but it never fails that in some areas on top of the car there will be some dirt showing. Would it reduce the buffing required to scrape it off as you have suggested for the run rather than the wet-sanding with 1500?

Yes you can use the Razor blade to mow down
bugs and dirt.

Gents,

Well I finally gave it a try and amost made it a sucess. The Blade idea worked great, but left me with a small bit of discoloring at the area of the sag. After the 1500 and 2000, I still had a bit of discolor. The rubbing compound got rid of most of that, but I still ended up with a Pencil line around where the sag was. I finally gave up and just pulled out the tape and paint gun. Thanks for all the input, it was great info.

Thanks,
Fred.

I painted my son's Firebird over the weekend and cannot express how much easier it is to fix problems when using the BC/CC paint than what I grew up with 25 years ago. This is my second experience with BC/CC and it gets easier every time, my 69 Chevelle convertible is up next. I had a few runs in the BC (probably because it doesn't shine like I expect it to), but I let it dry about 2 hours and just sanded them out with 800. Another coat of BC and it was fine, ready for the clear. Again, at the end of the 3rd coat of clear I overdid it on the bumper and got a real nice run. I tried the razor and did not feel comfortable about it, but at the body supply store they had a "nib" file which I bought for $10. This worked very well and only left about 2 minutes worth of sanding with 1200 and after buffing is invisible. The nib requires little experience and doesn't seem to scratch the paint other than the run itself. Anyway, with single stage paint I don't think it would be possible to get the same result as with BC/CC - it is very forgiving for us amatuers.