Handmade from the finest select woods and materials

Acoustic Archtop Guitars

by Southern California Luthier


Tad R. Brown

Finishing



Crystalac Brite Tone HVLP Guitar Finishing Instructions


Intro

A fantastic alternative to nitrocellulose lacquer is Crystalac Brite Tone. It is a non-toxic waterborne 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 lacquer 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 quite 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 very 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 that is nearly indistinguishable from lacquer.

While there’s still a small amount of VOCs, it’s more on the level of household paint. I do still wear a respirator while spraying, but afterwards, there are no lingering fumes anywhere near the way lacquer gasses for days.

Brite Tone is technically a type of acrylic-polyurethane, but not at all similar to the type of 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 more than adequate, but 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 technical info on the hvlp application of Brite Tone, and because switching to a viable non-toxic finishing process has been such a game changer for me personally, I am sharing my finishing schedule to advance the pool of shared knowledge. Not so much as an intro to guitar finishing, but for those who are already familiar with spray finishing and may be looking to move away from lacquer and toxic chemicals.

Overview

Relative to lacquer, the Brite Tone finishing process is essentially very similar. Building the clearcoat is a series of spraying and sanding sessions. Building up the surface, and then leveling the high points; each time becoming progressively smoother and flatter, until the final polished finish is as flat and smooth as glass.

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

For all it’s amazing properties, there is a learning curve involved in switching to Crystalac. 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.

Crystalac recommends 2-4 hours between coats, as it needs time to evaporate 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 between coats than lacquer. 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. Hot weather and low humidity can negatively affect proper flow out, but Crystalac makes a dedicated Viscosity Reducer/retarder. Recommended 3-5% reduction in hot dry conditions (above 80F or below 45% humidity), if the finish is drying too quickly and powdery and not flowing out properly. Lately I’ve been spraying a 95% mixture in all conditions, as the 5% reducer promotes all around smoother coats in general.

A word of caution on surface prep. Be sure to thoroughly clean all bare wood and surfaces to be coated with a solvent like acetone, in order to remove any oils, dust, and residue, to prevent any possible contamination or adherence issues. The base coat is absolutely critical to the adherence of all subsequent coats. Do not use sanding sealer as it is too soft and doesn’t bond as well. Use Brite Tone as the sealer instead. Brite Tone drys much harder than sealer and contains higher solids, making it an all around better sealer. All-Brite-Tone-to-Brite-Tone contact promotes the best possible bond to wood and finish for demanding applications such as lutherie.

Equipment

Apollo 7700 hvlp spray gun with a 1.0 mm needle. Set the material flow knob low, opened only about 1/2 to 3/4 turn, with the fan control set about halfway. Spray in slow, even, consistent, vertical overlapping passes from about 10-12 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 or 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.


How to achieve a flat thin glass-like professional finish


Surface Prep

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

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

Pore fill if needed with cyanoacrylate.

Block sand with 400 grit. Blow off the dust and wipe down with isopropyl alcohol, then two more coats of Brite Tone, 3 hours apart.

Repeat till all surfaces are completely flat and sealed, usually 2-3 sessions.

Color Coat

Mask and spray color. (liquid dyes or dry pigments mixed with 70-90% isopropyl alcohol and 25% Brite Tone as a binder)

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

Blow off the dust and wipe down the surface with Crystalac Surface Conditioner to remove dust and reside in preparation for the next coats. This is critically important, to promote the best possible bond and prevent any easily avoidable contamination 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 sanding too aggressively, 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 thin wet coats.

Drying

Hang and allow the instrument to fully dry for at least a month or longer. Patience in longer drying times ultimately equates to a harder finished surface that takes a better polish with less shrinkage down the road.

Pre-Polishing

Wet-sand the entire instrument with P2000 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. I like to stuff wads of paper towel into tuner holes and other critical areas for extra preventative. Now the entire 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 scratches, and keep polishing with the Abralon pad till they’re gone. Now the finish should be completely smooth, with a low gloss sheen.

Buffing

I use a 1HP 1725 RMP buffer 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 W-16 fine.

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, and 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 any remaining scratches with a soft clean microfiber cloth. The surface should be glossy and nearly flawless, with just a slight texture from the wheel burnishing the surface.

The extra fine soft flannel wheel then brings the finish up to a spectacular ultra high gloss.

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

Summary

Anyone looking for a viable lacquer alternative, or looking to rid their shop of toxic chemicals might want to take a serious look at Cyrstalac Brite Tone. It is a beautiful instrument finish that looks and sounds as good as traditional nitro lacquer, without the toxic solvents and associated health risks.

Cheers,

Tad R Brown

Brite Tone Instrument Finish / High Solids Polyurethane