FINISHING: Detail Lacquering Instructions

Detailed Lacquering Instructions - Skip Unless You Care:

First, Google Mike Doolin and read his advice regarding KTM-9. LMI's website also has some great testimonials about using this product. Don't try to spray it with a hobby air brush kit--it's too thick for those little nozzles and might cure in the air before hitting the surface.

For the novice (myself included) finishing a guitar seems fairly intimidating. After some research I concluded that using a water based finish would be better suited for me because a) it can be brushed on and I don't have an HPLV sprayer or a compressor or anywhere to spray it, and b) it won't blow up my home. Nitrocellulose lacquer has traditionally been the choice of luthiers, but because of points a) and b) (mostly b ) I chose to use a water based finish, which is said to cure just as well.

I used KTM-9 which is available from LMI. I know people who have used another waterbased products made by Oxford with equal or better results, and I will probably try it next time, but I am thus far extremely satisfied with the KTM-9.


-They say a quart will do 4-6 guitars, so I figured the $18 pint would more than do 1 guitar. WRONG! As a beginner, you'll likely blow through that. I was on coat 7 of 12-15 when I ran out, which caused a whole mess of problems I'll mention later. I bought a second pint for another $18, totalling $36 for lacquer. Had I spent $37 initially and bought the quart, I would have had twice as much lacquer and never run into a drying/bonding issue.


-You'll also want some of those cheap foam paint brushes from Home Depot. I used 3--since I applied lacquer in rotations of top, sides, and back, I cycled through the brushes. They rinse quickly with warm water and are dry within an hour. I've read about guys using bristle brushes for water based finishes. I never tried so I can't comment on them except to say that the flat beveled edge of the foam brush seemed to do a great job of applying a smooth finish (although tiny bubbles are an inevitability, they sand out easily and naturally).


The goal is to get about 12-15 thin coats, as level as you can. Sand every 3 coats with 400 grit and a felt sanding block. Watch that you don't sand too hard and through the finish. This stuff sands quickly and easily, and will gum up sand paper FAST. You'll be going through a lot of 400 grit sheets. Tack off before re-coating.

Make sure the epoxy sealed surface is smooth sanded (320 grit is fine) and use a tack cloth to de-lint it (but don't press too hard or you'll leave tacky goo on the surface).

I clamped my guitar body by the handle into a vice for the top and back, and held it by hand for the sides. Clamp the guitar at a slight downward slope with the high point being where you will begin brushing--not too steep, but just enough for gravity to help level the initial kablob of lacquer that will come off the brush as you touch the wood.

LOADING THE BRUSH- you will get the feel for this pretty quickly. Slowly dip the brush only EVER as deep as the bevel into the can. Leave it there 3-4 seconds. When you pull it out, a long linear drip will form and drip off, then stop. Dip it in again for 1-2 seconds, let the linear drip fall, and you're good. I recharged the brush after every head to tail brush pass for about 1-2 seconds--it took me about 7-8 overlapping passes per plate.

Let's use the back as our first surface. I gently touched the brush to the top binding edge side of the back, and slowly drew the brush toward the tail keeping the flat edge of the bevel in full contact with the surface, using moderate pressure. It is important to keep in mind that you are not brushing, but rather "applying" the lacquer. For the initial pass, it seemed that the brush would not fully charge with lacquer until pass 2, so lacquer-less streaks would appear toward the end of the first pass. Although I've read that others won't touch these areas until they've dried, I simply picked up the brush, went back 1 inch before the missed spot, and "rebrushed" the area continuing to the end of the pass. Bring the brush onto a wet area the way an airplane would land--be moving before you hit it. If the lacquer you just applied is only a couple of seconds old, you can retouch it, it self levels pretty well.

This stuff seems to brush on thick, but it seems nearly 80% of it evaporates, so you're really applying a very thin coat each time.

I brushed edge to edge, but always aware of how gently I was pushing down. If you push too hard when starting a pass, it will pool up and drip down the side. I would actually wipe up the drip quickly with a finger, assuming that I will have to sand that spot with 400 grit paper before coating the side.

If you're aware of your imaginary brushing "plane" you can brush right over the curvy edges of the upper and lower bout, and the sound hole in a straight trajectory.

KTM-9 tacks QUICKLY. Perhaps 2 minutes? Don't touch it after a few seconds, you'll fix it later.


I held the body by the neck-stick and started at the neck end (top), working my way all the way around. One technique I read about was to start the brush in the center of the side and brush outward toward the bindings at a 45-degree angle (kind of herringbone patterned). I tired this with mediocre results. (Perhaps I applied it too thick, I had wicked brush marks and major streaks). Instead I favored straight strokes side by side, and moving around the body about 6 inches at a time, always keeping the leading edges wet. It would be as if I had a big wide 3-4" brush that covered the whole side at once (don't try this however). You'll have to do the airplane landing thing with the brush though (engine noise sound effects don't actually help much). These passes actually dried fairly level. Since you'll be flipping the lollipop you've created a few times to get at all of the surfaces, continue to do this for about 10-15 seconds in each position (top up, then top down) a couple times after you've finished brushing the whole side, as this will allow drips and runs to even out. I then clamped it upright in the vice to dry.


I've read that you can apply 4-6 coats in a day--ha! Perhaps if you're a pro, or have no wife or family or job or didn't just eat a massive burrito the night before. But if you're a normal person or let alone a first timer, you'll be lucky to get through 3-4 coats in a "real" day (unless you have no wife, family, job, or little self respect and a good ventilation fan...)

I got a pretty good rotation going--brush #1 hit the top, dry 20 minutes while washing out brush. 20 minutes later use brush #2 to hit the back, dry 20 minutes, wash brush... This way you can theoretically get a full coat in an hour. After 2-3 coats depending on how they look, sand it level with 400 grit paper and a felt block. A coat only needs about 1 hour to dry before it can be messed with. Try not to hit the binding edges with the paper too much or you will eat through the lacquer there quickly.

CAVEAT! I ran out of lacquer at coat 7. I had to rush order another can, BUT between coats nearly 48 hours elapsed. I was worried because it's been said that after 24 hours you can run into adhesion issues. I had read that sanding the surface and wetting with denatured alcohol improves surface adhesion. I tried this and ran into major problems. Despite allowing the alcohol to evaporate for both a minute and 30 minutes, the alcohol did something nasty to the previous coat, and the subsequent coat congealed in weird pools-- it looked like I applied it with a sea sponge. In fact, it even peeled away at the sound hole. Perhaps this was just a fluke. I then sanded the entire coat off and continued on my way without incident. LESSON: DO NOT ALLOW MORE THAN 24 HOURS TO ELAPSE BETWEEN COATS! If you do, try a good sanding and see what happens-it worked for me.

Once you're satisfied that you've got enough coats, hang it up and let it cure for at least 2 weeks. The finish will harden and shrink during this time. It should look pretty shiny but probably not smooth--it's ok if it looks a little matte as you'll be sanding and buffing it up later.