Best finish for Mahogany

Hi Everyone! I'm in the final stages of my first kit build- a modified Stew Mac mahogany soprano...I purchased a gloss spray lacquer for guitars and wanted to know if this spray will possibly dull the tone. Any thoughts comments or suggestions will be greatly appreciated!
BTW- I really had fun with this and am looking into creating my next one from scratch!
Thanks!
Nancy

Lacquer can alter the sound somewhat but the right amount of finish can actually enhance the sound. Too much lacquer though will just add mass and make it less responsive. Just make sure your finish is thin enough to do it's job yet thick enough to withstand the use it'll get. I use a yogurt cup lid under the sound hole (backed by a large square of sponge) when I spray. The lacquer will not stick to the plastic lid so it's easy to peel it off after you've sprayed some coats and measure it with a micrometer. Remember though that the lacquer will shrink a lot as the uke continues to dry (up to a year or more) and also take into account that the thickness will be reduced if you do much sanding. Keep notes on your finish thickness to guide you when you build your next uke.

Moore Bettah Ukuleles said:

Lacquer can alter the sound somewhat but the right amount of finish can actually enhance the sound. ...

Click to expand...

I'm glad there's at least one other person on the planet that believes that!

The sound we are all after is very subjective, but I think generally it's generally agreed that less finish is better than more. By adjusting the amount of finish you use on the top and back of the instrument you can change the resonant frequency making it brighter or duller, depending upon where you started and what you want as the final result. Increasing the mass of the finish will lower the frequency, decreasing it will raise it. Keep in mind these things are best evaluated after the lacquer has time to fully cure (losing mass while becoming stiffer), perhaps after a year or more. I believe this is why many ukes will become brighter (or open up) after they sit for a while, whether they are played or not. Of course the finish isn't the first area I'd look to to make those adjustments but it can't be ignored that it has an effect. Sometimes better, sometimes worse. That's why finishing is an art.

Thanks so much Chuck! I really appreciate you taking to time to help me out with this! The sponge and yogurt top is a great idea, I'll spray the uke lightly and keep the finish nice and even. I inlayed a fragile piece of old marquetry down the fret board and was wondering if it would be all right for me to use a brush on lacquer, avoiding contact with the frets, over this inlay... I also sculpted the headstock and am thinking of creating a fun tiki image in wood stains and incorporate the bridge into the design... I'll post a few photos as soon as it's done!
Thanks again!
Nancy

When you say you'll spray the uke lightly I hope you mean you won't build up too much lacquer. Every coat of lacquer should be applied "wet". This means you need to spray enough lacquer quickly to achieve a wet look without causing any runs or sags. It's easier to do this with lacquer sprayed with a gun so that you can adjust your mix to flow properly but on a small area such as you have with an ukulele it can be done with rattle cans. If you spray "lightly" you're not going to get a smooth finish. You didn't mention whether or not you intend to sand and buff the uke. If so you need to take that into consideration and build up a few additional coats.

Grain fill is another consideration with Mahogany. It is a very open pored wood. In lacquer finishing open pored woods without grain filling, personally, I think there is a limit to how much lacquer that can be applied to the wood before it starts looking weird. With lacquer from a can, thinned maybe 20%-30%, sprayed in wet coats, I find this limit to be about 3 coats. ( I spray Cardinal lacquer more thinned than that. ) Beyond that, I do not like the look any more. Rattle can lacquer is much thinner, it is pretty low solids in comparison to the stuff you buy in a can to spray through professional finishing equipment. As Chuck said, the coats really need to be wet, each pass flowing into a fully wet film. When just learning, it can be easy to get runs. If it is just sprayed in a manner so that little lacquer droplets just stack up on the surface, not flowing together, you won't get any runs, but you won't get a smooth finish either. I have not tried polishing a finish that was sprayed in a manner that did not 'flow' into a wet film, as I always try to spray a glassy wet film, but I thing that with gloss lacquer, a poorly sprayed finish would not polish correctly.

For someone just starting out, I might buy a practice can of the same material, and practice spraying wet coats that flow together. I would pick up a rattle can of Bullseye shellac , and practice with that too, as the shellac really comes out of those fast, best to hold the nozzle 16" away or so.. Then spray a single wet coat of shellac, sand it back trying not to sand through, careful at the edges. If a touch up coat, or another full coat is necessary, go for it. The shellac will build fast, so keep it thin. (but wet) Sand it again so you have a smooth thin coating of shellac all over, then spray, probably 3 wet coats with the rattle can lacquer, maybe 4, light sanding between coats as necessary, and call it good. Practice on some Mahogany, you will see the point where the finish builds up and starts to look weird if it is not filled. if you are not filling, I would aim for a thin dry film. The shellac under lacquer acts as a great base for the lacquer, and will help with the long term color of the instrument. Straight lacquer on raw Mahogany looks sterile to me after a little time, t does not go to that deep red that makes Mahogany such a special wood.

Really, a nice lacquer finish on Mahogany needs the grain filled.

For a beginner, buffing is a whole can of worms that may or may not prove to be fun! Buffing an unfilled, open pored finish can also prove to be a nightmare with buffing compounds building up in the pores.

Practice the entire process, patiently. If you are happy with the results, then you will probably be happy with your uke finish too. If not, figure out what is not working. Allow a full day for the shellac to dry before top coating with lacquer. You can spray all the lacquer coats in one day, but I find that a better finish happens when more time is allowed for all the coats to be built up.