Applying Finish To the Guitar
By John Fisher
"Experience is a great thing--it helps you recognise your mistakes every time you make them again."
The main Lesson Learned while Finishing this Guitar!
NEVER PAINT YOUR GUITAR ON A DUSTY ROAD SIDE IN PERU!!
To get a good finish to me is one of the hardest things to me about building a guitar. Of Course now that I think about it, almost every aspect about building a guitar is tedious. Each phase is a whole project in itself.
One nice thing about using lacquer for the finish is that lacquer can be worked on and any defects can be corrected or sanded off and re-touched up. I used "acrylic lacquer" instead of "nitrocellulose" lacquer which from what I understand is a tuff finish that doesn't crack as easy as nitrocellulose lacquer.
I am not going to give a complete tutorial on how to lacquer a guitar but I will just touch on some of the experiences (mainly setbacks) that I had and some of the things I learned.
There are many good products and tools available to conquer the many difficulties that you will encounter finishing a guitar. To be honest I lack a lot of experience with those products so I am just letting you know what I did. You probably realized by now that I am quite unconventional in my approach to the tasks at hand. That's what makes this article different then what you would normally get out of a book. But by all means, you should get the book too. My hope is to just inspire a bit of ingenuity. What the heck! I'm just having fun!
It is imperative to have everything well sanded. It takes a lot of time to do it right but it's worth it. Because of the fact that most of the guitar I built is painted a solid color, that was helpful in the fact that I was able to fill in many bad spots with auto body putty that were unseen when finished. I started with heavy sandpaper when needed, then worked finer and finer until I finished with #280 grit paper. I found that it's important to work your way up gradually with the intermediate grades of sandpaper. If you skip grades or stages you will have a smooth surface with distinct scratches in it.
Once sanded to satisfaction, I rubbed a damp (not too wet) cloth over the surface then let it dry. This would raise the grain a little. Then I would sand again with the #280 paper. After dusting off the surface with a cloth, by hand with cotton I applied a very thin coat of lacquer based sanding sealer. It would dry quickly then I would re-sand the surface with #400 paper. This will immediately show you parts that were not perfectly sanded or not shaped correctly and especially with the carved top, it will give you an idea how the curvature of the top will come out. I then carefully masked the binding and the fret board with masking tape.
I then sprayed about 3 coats of lacquer (2 parts thinner and 1 part lacquer) and let it dry for an hour or so.
I then sanded it down a bit with #400 sandpaper
I then prepared some of the same clear lacquer with a tiny bit of stain in it.
I applied a couple of coats of stain until I reached the density of the stain I desired. In this case, I made it a bit dark but with the grain of the wood still showing.
With the same lacquer I just used for the staining I added a bit more stain the then very lightly began the sunburst around the edge.
I then started to mix a tiny bit of black with it and sprayed another layer around the edge of the guitar. This time slightly further from the center then the last time.
I then added a little more black and went around again getting a little further away from the center.
Finally I went around the last time with straight black tinted lacquer on the very edge or perimeter of the top. The idea is to make a smooth transition from the stain starts to get dark to the edge which is black.
I then put several coats of clear over it. (Just the top)
I then let it dry for a day then I masked the top so I can spray the back black.
I screwed the bridge posts in to protect the top from being scratched while I laid it flat to do the back.
On the back I put a few coats of black tinted lacquer then a few coats of clear over it. I waited about 20 minutes in between coats.
I then let the guitar dry for a day or 2.
I then removed the masking and wet sanded the whole guitar with #400 sandpaper to get a great deal (not all) of the orange peel effect off. I was careful not to go too far where I would sand through the stain.
At this point I drop filled with a match stick any indentations or dings in the finish with thick lacquer.
When dry, I would carefully sand down flat the drop filled lacquer.
I then spayed several more coats on in about 20 minute intervals until I knew I had a good finish.
I then waited at least a week (some people wait a lot longer) then I wet sanded with #400 until there was no orange peel effect left. There should be a good enough coat on by now that all the blemishes can be sanded out. If there was still some deep dings in the finish I would drop fill them with lacquer and sand them down flat.
Once everything is flat with a good finish and no more dings I wet sanded with #600 paper, then a bit with #800, then a bit with #1000, then a little finer, #1500.
By then my finish was pretty good so I started to rub some red rubbing compound on. I let it dry for a minute then with a soft cotton cloth rubbed like crazy until I started to get a mirror like shine.
There are buffing wheels that you can get to put on your electric drill to do the job a lot faster but you have to be careful. If the lacquer is not really hard which can sometimes take months, you can ruin the finish. When the lacquer is not completely cured or dried it will be hard on the surface like a scab but underneath it can still be soft. When buffing with a cloth or a buffing wheel, besides the fact that the rubbing compound is polishing it with a very fine sand in the compound the cloth or buffing wheel is also causing friction and actually slightly melting the finish to where it smoothes it microscopically which creates a high gloss.
I finished it by applying some white rubbing compound which is even a little finer in the same manner as the red. By then I had a high gloss finish.
Some Problems I Encountered
I realized that the weather really had to be dry. If I tried to paint on a humid day or when the sun was setting I would get fogging in my finish. That's moisture that gets into the lacquer while spraying. The lacquer gets foggy because of miniature bubbles in the finish.
At one point after waiting a day for it to dry, I re-sprayed it with a thin coat mixed with lots of thinner. It seemed to work fine but when I went to sand it down you could see a slight witness line wherever I sanded through to the previous coat. I later found out that the problem was that I had used too much thinner in my mixture and to a certain extent the lacquer was drying a bit before it would unite with the previous coat.
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