Help, problems buffing out lacquer.

[CGHbuilder86]

I am working on buffing out a nitro lacquer finish. I am using a buffing arbor that uses a motor and pulley to run. It’s the kind Stewart MacDonald sells. I am using the menzerna dry buffing compound, grades fine, and very fine. I am running the buffs at about 862 rpms. Before buffing I wet sanded in grades of 800, 1,000, 1,200, 1,500, and 2,000 grits. The problem I am having is that if you look at the finish across the guitar it looks wonderful, but if you look straight down on the finish and the light hits it right it looks bad scratched and dull. The top looks pretty good the neck also looks pretty good, it’s mainly the dark rosewood back and sides that are giving me this trouble. Any help on this would be appreciated. Thanks!

[RAI6]

It almost sounds like your clear is doing just fine, but your "color" isn't....

Was your color coat "perfect" before you sprayed the clear?

[LGM Guitars]

Fine and extra fine probably aren't coarse enough to get rid of the 2000 grit scratches, though I suspect you didn't sand out all the 800 scratches far enough. With Nitro you should be able to get them all out easily though. Its pretty soft. You shouldn't have sanded your final coat with anything coarser than 1500 though, it wil be a lot of work to get all the scratches out now, start with a coarser compound first.

[CGHbuilder86]

Thanks for the previous reply’s to my questions they have been very helpful. But I’m still having a little problem.

I thought the easiest way to remove the deep sanding scratches would be to spray two more coats of lacquer, so after sanding with 400 grit paper to give a nice tacky surface I sprayed two coats of lacquer. Then I let it cure for four days, after letting it cure, I sanded with 1500 grit paper and followed with 2000 grit. Now the fine compound that I started buffing with is supposed to remove 1000 grit and above sanding scratches, so I don’t think that is giving me my problem. I also followed the fine compound with extra fine. Now after I finished all the buffing, to look at the finish in light from regular light bulbs, it looks pretty good, not perfect though, but when I look at the finish under florescent lights it looks worse. There are some very fine sanding scratches, and it does not look as clear as it should, It’s just a little dull looking when the light hits it right.

Could letting it cure for only four days cause it to look a little unclear?

I also used an off brand cheap lacquer thinner to improve the spraying, this wound not be causing my problem would it? Any help on this would be appreciated.

[butnut]

The short cure time could be it. A lot of guys on the Reranch wait weeks before final sand/buff with nitro...that's why I like poly. It also depends on spraying conditions (hot/humid?) as that will affect drying too. Also how many coats, how thick you last spray went on...no one likes watching paint dry, but with lacquers, they don't have the catalyst like poly does, so it's always best to give it as much time as possible to cure before buffing.

[Drak]

I thought the easiest way to remove the deep sanding scratches would be to spray two more coats of lacquer.

Well, yes maybe, except you used cheap thinner, which dries -very- quickly (too quickly for pro finishes really) and may not have given the lacquer a good chance to dissolve itself -thoroughly- into the undercoats that were deep-scratched in the first place.

so after sanding with 400 grit paper to give a nice tacky surface.

Freakin' OUCH! Too coarse for being almost done.

I sprayed two coats of lacquer. Then I let it cure for four days.

Stop! ...4 days? Try 4 WEEKS!

after letting it cure

You have very minimal cure after 4 days. Patience at this part of the game is soooooooooooo important, you have to learn to hold yourself back, you're just damaging what it took so long to do in the first place. Tough, yeah, I know.