Tip: Cutting and Buffing Paint

[RV8R999]

Dan you have given me hope my very mediocre paint job can actually be salvaged or at least improved! Thanks

Ken

[Mike S]

Originally Posted by chinch

...in unrelated news, 3M shares have risen two hundred points this morning on unconfirmed reports of a massive and as yet unexplained spike in sales by their cutting and polishing products division....

[rv9aviator]

As always, THANKS Dan.

I am curious about the paint color. It looks like VW Bug metallic light green. That's not the proper name just what I call it. I remember there was a fellow that designed his own plane a while back and it made all the magazines. Very sleek composite plane. He painted the whole plane with VW Bug light yellow metallic. It was beautiful.

[DanH]

Originally Posted by RV8R999

Dan you have given me hope my very mediocre paint job can actually be salvaged or at least improved!

Most paint can be improved, even a very good hired gun job. As I mentioned elsewhere, this work has become routine in the autobody world. Even pros don't spray perfect paint every time.

Two quick notes. Less need to worry about rivet lines if your first pre-paint step is a good scuff with a 400 grit stick-on disc on a hard backup pad (clean, sand, clean again). Look close at the rivet heads when you pass over them and you'll immediately see any which are not flush. Block sand, shave, or replace and they won't haunt you later in the cut and buff stage. If you didn't do something like that and your paint is now on the airplane, make a light pass down the rivet lines with the 1500 disc, wipe clean, and study the heads. If the dulled (cut) surface forms a sharp line at the rivet edge, better watch out. Mark that one with a tape dot and stay off it with the sander. Really nervous about the rivet lines? Fine, don't sand them at all! You can sand just the middles between the rivet lines, then buff the whole surface. The result will mostly fool the eye of the observer; without the light just right he won't see the little bit of orange peel along the rivet lines.....the majority of the surface is slick.

Second thing.....none of this will work if you don't have enough paint on the surface. If you sprayed a very light, barely covered, every-ounce-counts paint job, perhaps you should forget about cutting and buffing...or at least the cutting part. The pro who does my car work shoots a very light tack coat of clear, then two wet coats. That's his comfort level in case he needs to cut it later. I sprayed a tack coat and three wet coats, the extra coat being insurance, and besides, I like the deep look over the pearl base.



Moral of the story is "decide early". If you think you'll cut and buff, give yourself all the advantages from early in the paint process.

Jim: The color in the oil door photo is actually GM Silver Birch....the camera made it look green. The builder with the beautiful yellow composite airplane was Cory Bird.

[n180tf]

Is what you are doing only for base coat/clear coat? Can I use it on a single stage urethane like Air-tech, or Superflite?

[wyoflyer]

Thanks for the info Dan. One tip that really helped speed up the cutting and buffing process was a squegee. After the rinse, use the squegee to wipe off the sanded paint and water. One swipe and the surface is dry. Saved a lot of paper towels.

[DanH]

Originally Posted by n180tf

Is what you are doing only for base coat/clear coat? Can I use it on a single stage urethane like Air-tech, or Superflite?

Certainly with a single-stage two-part auto paint. However, I can't speak specifically for Air-Tech or Superflite. Best I know, the polyurethanes for fabric airplanes are highly plasticized; they have to be or they would crack when the fabric stretches and flexes. I have no idea how well they sand and polish; never tried 'em. It's easy to find out. In my auto shop we get all kinds of paint finishes, so the first thing you teach a new detailer is to test solvents and polish methods on some out-of-the-way place on the car....a door jamb, under a trunk lid, whatever. Same goes here. Nobody will ever look real close at the underside of your wheel pants

FWIW, I've sprayed a good bit of Polyfiber Aerothane and a little Superflite. The auto paints are a lot easier to spray and seem to present less of a health risk.

[szicree]

All of Dan's cut/buff info is spot on; however, one thing you have to be aware of if sanding into a single-stage is that the color can lighten as the paint gets thinner. Obviously, this can result in uneven coverage and look like heck. If the paint is nice and thick and the orange peel very slight things will go fine.

[Dan Langhout]

Originally Posted by szicree

All of Dan's cut/buff info is spot on; however, one thing you have to be aware of if sanding into a single-stage is that the color can lighten as the paint gets thinner. Obviously, this can result in uneven coverage and look like heck. If the paint is nice and thick and the orange peel very slight things will go fine.

Do NOT do this on single stage metallic colors unless you like to live dangerously! As you cut down into metallics, you will tend to end up with a mottled or striped look due to uneven exposure of the metallic particles in the paint (ask me how I know ). Not a problem with base/clear metallics since you are cutting in the clear rather than the color.

[jsharkey]

Messrs Rolls and Royce would be proud