Brushing laquer

[Matthew Atkinson]

I am trying to put a nice "last" coat on my guitar project. I am using "brushing" laquer. For some reason on the top I can't get it to flow smoothly enough. The back and sides came out ok. I am worried about drips on the edges and at the soundhole so I can't get a smooth stroke with the brush. Any suggestions? I have 3 coats on it now. 2 on the back. Shellac sealed. It says "do not thin" on the can but I sure want to try.

[John Hamlett]

I'd try thinning it just to spite the label!
If you have some lacquer retarder, that's what I'd add to it, either that or the slowest thinner you can find. Alas, different "speeds" of lacquer thinner aren't as easy to find since the days of spraying lacquer on cars are mostly over, and lacquer thinner from the hardware store; "wash grade" thinner, may not be much help.

[Clay Schaeffer]

Hi Matthew,
I've thinned brushing lacquer to spray it. If you are brushing it I'm not sure thinning it will help it flow out any better. Most lacquer thinners speed up the drying time. Butyl cellosolve (retarder) as John mentioned, might be your best bet.
With Lacquer the smoothest surface is often achieved by sanding and buffing the cured finish. Brushing lacquer builds thickness faster than sprayed lacquer so you won't need as many coats, but I would still allow it to cure a few weeks before buffing.

[Bryan Bear]

I have never used brushing lacquer so I may be way off here, but could you get better flow off the brush by warming* the lacquer can?

* please be safe if trying to warm a can of flammable liquid! I'm thinking warm water bath not a flame, heatgun, space heater or any of the other horrible ideas that are flashing through my brain.

[Clay Schaeffer]

A good brush will make a difference, but a good brush will cost as much as a cheap spray gun.

[Nicholas Blanton]

My first experience with brushing lacquer was similar. I did get it to work better by thinning it down, to where it would flow nicely from the brush and not always be dripping and sagging, using a fine brush that didn't leave too many hairs in the finish, and -very importantly- not overbrushing. You lay down stripes slightly overlapping, with a brush that's not very wet, and if you leave a bare spot you don't go back and brush again, you just wait for that coat to dry and apply another coat. If you try to overbrush and catch the bare spot or smooth out brush marks, you'll mess up the finish underneath, because it's been softened by the finish you just laid down. The idea is to build up enough coats so you can level it all and then polish it up.

I agree, spraying lacquer is now not that expensive and works faster than brushing. But the same very fine nylon watercolor brushes that work for spirit varnishing would likely work for this as well, and they are not too pricey. MUCH cheaper than the wide fine-hair watercolor brushes I once used for spirit varnishing...I inherited a big one from my grandfather that was worth about $90, and I kept it carefully for years until I got careless and some moths got into it. Moths don't eat nylon. At least, not yet.