groa944

Question for you.
I'm in the middle of repainting one of my audis. I'm trying to do this one as practice for the 944.

I'm trying to strip off all of the clearcoat, as it's a graphite metallic color with a clearcoat that has failed in spots. The clearcoat is extremely time consuming to sand off. I'm using 80grit 3M sandblaster sandpaper on a porter cable finishing sander (electric type, some people would call it a jitterbug sander).
I think it took me most of 6 hours to sand the top of the hood down to the original primer. Obviously the name "finishing sander" would make one think it's not for major paint removal.

My question is this. Would the removal of the clearcoat and the underlying paint be quicker with a random orbit sander? I was looking at those today while I was out shopping for tools, and wondered if they would speed things up. I know they use rotating sanders on all of the cool car shows, but I don't know if this is the same thing as I am thinking it is.

Other than that everything is going great. I'm using dupont's omni series epoxy primer at the moment, which looks great. It's just taking so long to get areas prepped, that this is going to take another 6 months to finish.

Thanks for any advice!

xsboost90

i use a da sander- Hutchinson- dual action sander or orbital i guess. THis takes 7"-i think?- da paper from the paint store w/ the sticky paper on the back. THis works much better than a jitterbug would. Sand it all down w/ the 80 grit, smooth as possible, primer- i use evercoat euro primer in the pink can-only $50 for gallon+activator at koi- and then sand w/ a hand block and some 180/320/500 w/ primer coats in between if you need. when you hit 500 your ready to paint. Use water w/ the 500.

groa944

Do you know if they sell dual action sanders that are electric, or are they all pneumatic?
My air compressor that I have now won't support the CFM requirements of one of the pneumatic types.

I'm putting the epoxy primer down, then I have a urethane high build primer to put on that. The urethane will be smoothed, then I'll paint over that.

Also, I have a couple of areas that will need a skim coat of filler. Should I put that on top of the epoxy primer, or in between coats of the urethane?

Thanks!

xsboost90

im pretty sure someone sells them in electric. ie milwaukee or someone.

sometimes if you follow the rules of the bodywork book, you will go broke. THEY have epoxy primer, then eurethane primer for fill, then sealer primer, then onwards.......i only use euro primer but i would put the epoxy primer on first.

groa944

Groovy. I'll try and find an electric version. I hate sanding, especially when it takes this amount of time. It makes me dread working on the project.

I'll have to check for the euro primer. I've not heard of that before. The epoxy primer sure is sweet though. It just looks badass when you put it down. Looks like you could take a chisel to it, and it would still be fine.

Thanks again!

pete944

Porter Cable makes a good orbital sander.

http://www.porter-cable.com/index.asp?e=547&p=2777

groa944

That's pretty. I may have to get that. Now the only question is, is a random orbit sander the same as a dual action sander? I think so, but nowhere tells me for sure.
I'll keep checking on it.

pete944

Yep, same thing as far as I know.

groa944

Cool. I'm going to head out and get one tomorrow. I like the porter cable, and there's a nice looking ridgid brand one as well that looks pretty nice. Hopefully they'll speed things up a bit.

Lead Foot 944

I swear by my Snap-on orbital.....Its been used every day for about the last 2 yrs, and no problems yet.....But It was pricy, about $250.....And remember, to fill 80 grit sanding scratches with primer, well that would be something Macco would do, I like to go over all of my bodywork that requires primer with at least 240 to 320.....and about 600 to 800 wet on nice cars like mine.....primer does not fill everything...just a pointer for you...


DAmian

Wade B

Very good point. Don't rely on the primer to do the "heavy" filler work. Just keep "building up" the surface with regular primer(s) and sanding smooth with higher grit paper.

Past experience has taught me to stay away from the high build primers. Once they settle, and the sanding scratches start showing through, (like 6 months after you've painted the car!) it makes you wish you would have taken more time and labor and done it more slowly.

Adam H

Porter-Cable makes good stuff.

xsboost90

well, the eurethane primers are much better quality than the old laquer primers which ALL shrink unless you have a bake booth. The smoother it is when you prime definitly the better off you will be in the long run. I have a friend whos car was fixed in the body shop and looks like they did some 40 grit then primed it or something....

groa944

Well, when I am putting down the epoxy primer, it smooths out the surface quite well. I'm not getting very deep scratches to start with, not what you'd expect from a 80grit. When the epoxy is down, it looks pretty smooth.
I'll then go back with several coats of the high build urethane, and smooth that out with a 300 or 400 series paper to get my final surface.

I was doing some research Wade, and came up with the same response Dan gave. The newer urethane primers don't shrink the way the older types did.

It's looking really good so far, just taking forever.

I think I've settled on a sander. Ridgid sells a random orbit 6" electric sander with two orbit selections. One is more aggressive, and one is finer. It's also variable speed, and has some very good reviews.
It's made by Metabo, which makes some excellent products.