Handmade from the finest select woods and materials

Acoustic Archtop Guitars

by Master Luthier


Tad R. Brown

Finishing



Crystalac Brite Tone HVLP Guitar Finishing Instructions


A fantastic alternative to nitrocellulose lacquer is Crystalac Brite Tone. It is a non-toxic waterborne urethane instrument finish that looks and sounds as good as traditional lacquer, without the toxic solvents and noxious fumes. Long term exposure to lacquer solvents is well known to have serious health consequences. After becoming sensitive to noxious fumes I was seriously considering outsourcing the finishing process until I discovered Crystalac. But the real question is, yes it is non-toxic, but is it as good as lacquer? I can state unequivocally, yes!

Most waterborne products have a bad reputation, because historically speaking, most alternative products marketed to luthiers have never lived up to the old standard of nitro lacquer, but Crystalac is a notable exception. Brite Tone is the best waterborne guitar ‘lacquer’ that has ever been developed. It is crystal clear, dries hard, doesn’t blue, doesn’t fish-eye, doesn’t check, doesn’t hurt tone, and can be wet sanded without streaking or cracking. It has properties similar to lacquer in that each coat burns into the previous coat, shrinks while it dries, sounds great, and buffs to an exceptionally smooth high gloss, making the final polished finish indistinguishable from lacquer.

Brite Tone is technically a type of polyurethane, but not at all similar to the polyester resin that most people think of as ‘poly’. It is nowhere near as thick and bulletproof. More similar to lacquer in how thin the coats build and how scratch/dent resistant it is. That is to say, like lacquer, durability is adequate, and not nearly as super tough and deadening as polyester. Brite Tone, when applied in moderation, is tonally transparent, like lacquer.

Since there is very little advanced instructional info on the professional application of Brite Tone available, and because switching to a viable non-toxic finishing process has been such a game changer for me personally, I decided to write this article, to advance the pool of shared knowledge, for better results for all. Relative to lacquer, the Brite Tone finishing process is essentially very similar. This guide is not so much intended to be an intro to guitar finishing, as it is for those who are already familiar with hvlp spray finishing and may be looking to get away from spraying lacquer.

For all it’s amazing qualities, there is a learning curve involved in switching from lacquer to Brite Tone. It is not as forgiving to spray as lacquer and drips easier. The sweet spot is narrower. It’s all about good spray-gun technique, and laying down smooth thin wet coats.

Equipment:

I like the Apollo 7700 spray gun with a 1.0 mm needle. Set the material flow knob low, opened only a little more than 1/2 turn, with the fan control set about halfway. Spray in slow, even, consistent, vertical overlapping passes from about 8 inches away, while keeping a close eye on the flow-out. There should be just enough liquid material hitting the surface to flow out nicely without dripping. If you’re getting drips, move the gun faster and turn the flow knob down. Be sure to have enough turbine pressure to spray full strength without needing to thin, about 7psi 130 cfm.

Cleaning up is easy with just warm soapy water, and they also make a dedicated Spray Gun Cleaner, vinegar-type solution for dissolving residue from other finishes.

Another plus is that Brite Tone is easier to sand than lacquer. No gummy pigtails, sands like a dream; cuts to clean white powder. Gold sandpaper works fantastic, and causes no fish-eye issues.

Overview:

Crystalac recommends 2-4 hours between coats, as it needs enough time to dry before re-coating. I’ve found 3 hours between coats and 3 coats a day to be ideal in normal temperature and humidity ranges. It dries to the touch in less than 15 mins, but needs more time to fully evaporate between coats. Ultimately, patience in building the clear top coat allows the final finish to cure faster with less shrinkage. Blushing can occur in cool or humid weather, but does not need any special treatment to free up the trapped moisture, unlike like lacquer which often does. The blush will simply evaporate and disappear as it dries. Low humidity can affect proper flow out, but there is a dedicated Viscosity Reducer. Recommended 5% reduction in dry conditions below 45% humidity.

A word of caution on surface prep. Be sure to thoroughly clean all surfaces to be coated with a solvent like acetone, in order to remove any oils/dust/residue, to promote the best possible finish bond and prevent any possible adherence issues. Do not use sanding sealer. Seal bare wood only with Brite Tone instrument finish.


How to achieve a flat thin glass-like professional finish

Surface Prep:

Sand bare wood to 220, blow off the dust, and thoroughly clean all surfaces with acetone.

Seal all surfaces with 2 coats of Brite Tone Instrument Finish, 3 hours apart.

Pore fill as needed with cyanoacrylate.

Block sand back to completely flat and level with 400 grit. Blow off the dust with compressed air and wipe down with alcohol instead of acetone to avoid softening the ca glue, then two more coats of Brite Tone, 3 hours apart.

Repeat till all surfaces are completely flat and sealed, usually 2-4 sessions.

Color Coat:

Mask and spray color. (Dye/pigment mixed with alcohol and 25% Brite Tone)

Pull tape and detail.

Clear Top Coats:

3 coats of Brite Tone, 3 hours apart, dry overnight. 2 to 3 more coats the next day, dry overnight.

Carefully and very lightly cut down just the high prickly points with 400 grit on flat and curved sanding blocks. Do not attempt to sand fully level yet, and do not go through into the color coat!

Blow off the dust and wipe down the surface with acetone or Crystalac Surface Conditioner to remove all dust and reside in preparation for the next coats. This is critically important, to promote the best possible bond and prevent easily avoidable contaminant problems.

3 more coats of Brite Tone, 3 hours apart, dry overnight. 2 to 3 more coats the next day, dry overnight.

Block sand partially level with 400, leaving pores and depressions. Those will fill in during the following sessions. Better to spray more coats and be conservative about leveling, rather than too aggressively trying to level out low areas, which could result in a sand-through.

3 to 5 more coats should be enough to sand almost entirely flat and level, leaving only a few tiny tiny pores here and there.

3 final perfectly smooth coats.

Drying:

Hang the instrument and allow to fully dry for at least two weeks minimum, but preferably a month or longer. Patience in longer drying times ultimately equates to a harder glass-like finished surface that takes a better polish.

Polishing:

Wet sand the entire instrument with 1500 grit on curved and flat blocks. Work small areas at a time with a very minimal amount of water, wiping up with a soft clean microfiber towel frequently. Do not allow water to run into f-holes, sound holes, tuner holes, or any unsealed surfaces! Water can swell bare wood and crack the finish, but finished areas will be effectively sealed and waterproof. Now the surface should be completely flat with a satin sheen.

With a random orbit palm sander on low, gently wet polish the entire instrument with a 2000 grit Abralon pad backed by a soft interface. Don’t use too much water. The Abralon pad should be moist, but not dripping wet. It will need to be washed and wrung out several times as finish residue builds up.

Carefully inspect for any remaining 1500 grit scratches, and keep polishing with the Abralon pad till they’re gone. Now the finish should be completely smooth, with a low gloss sheen.

On to machine buffing. I use a 1HP 1725 RMP arbor with two 12″ wheels. On one side is a hard 60/60 cotton wheel with pink Menzerna P-204 medium cut compound. On the other side is a soft bleached domet flannel wheel with Menzerna extra fine P-175.

This is the most dangerous part of the finishing process. Be especially careful around edges, corners, f-holes, and soundholes. Light, controlled passes. Let the compound do the cutting, not too much pressure, keep moving, don’t let the surface heat up. Also be sure to wear a respirator and eye protection.

A beautiful high gloss finish should easily be achieved with the medium buffing wheel by gently polishing in alternating directions. Inspect for scratches with a soft clean microfiber cloth. The surface should be glossy and nearly perfect looking, with just a slight texture from the wheel burnishing the surface.

Repeat this process with the extra fine soft flannel wheel, bringing the finish up to an incredible ultra high gloss.

Final step, hand polish with Meguiars Ultimate liquid wax. This lends the ultimate deep wet smooth glassy shine, and cleans up any remaining lint and compound dust. Also makes a great guitar polish for removing sweat and fingerprints.

In summary, anyone looking for a viable lacquer alternative, or looking to rid their shop of toxic chemicals should be taking a serious look at Cyrstalac Brite Tone. It is an excellent instrument finish that looks and sounds as good as traditional nitro lacquer, without the toxic solvents and associated health risks.

Cheers,

Tad R Brown