Buffing lacquer

[thistle3585]

I just upgraded my buffing system to a wheel versus by drill with a foam pad. Is there an ideal time frame in which to buff out lacquer? I know I can buff too early, but I wondered if I can wait too long? Right now I'm letting it dry about 7-10 days after spraying 2-3 coats a day over the course of a week. Will an overly cured finish be too hard to buff?

[Jim Rowland]

It's another one of "those" things,Andrew. Some say the longer they hang the better;some buff out in a day or two. For the common lacquer with an acceptable content of solids, I try to let them hang for at least two weeks in a warm,low humidity area. I've buffed out a couple which hang dried for much longer because I was into something else with no discernable difference. I doubt that a finish could be too hard because it is over cured,or even if it can be over cured. I could be wrong.
Jim

[sunburst]

Lacquer shrinks for quite a while as it continues to "dry" (loose volatiles). If you buff early, it will shrink more after it's buffed, so grain lines, pores, sand scratches and all that will show up more. If you buff a little later, the surface will stay more nearly level.
As the lacquer continues to shrink the film gets thinner, so waiting too long makes it more likely that you will sand or buff through trying to level the surface, otherwise, waiting a long time is generally best for maintaining the level, glossy look of freshly buffed lacquer.

I like to wait at least two weeks before buffing lacquer, but I seldom can leave instruments curing for that long because there's usally someone waiting on them, so I usually buff between one and two weeks after the last coat.

[Hans]

Yup, depends on whether you want a car finish or the violin look with grain, pores and all. Here's something to consider. If you go with the violin look you can put fewer coats on, and end up with a thinner finish. You sand and buff a day after you put the last coat on and the finish is still "thick". It hasn't shrunk down much. Level it out now and buff and then let it shrink. You use fewer coats...