Classical Guitar Repair
Some Free Advice for Aspiring Guitar Makers. And Players, Please Take Care of Your Guitar!
My journey into guitar repair started with my first guitars, when you mess up the guitar you are making, you have to figure out how to fix it. When my wife and I lived in Colorado, I did guitar repairs for local guitarists that I knew, then the word got out among the college students at Metropolitan State University, Denver; University of Colorado, Boulder and Colorado State University, Fort Collins, and I had more repair work than I needed. People would ask me to adjust the actions on their guitars, maybe fix a crack, replace tuning machines, or in one case replace a guitar top. I enjoyed the work, but quickly realized that to profit at guitar repair I would need lots and lots of repair work, which is not my goal as a guitar maker. My goal is to make and sell guitars.
A little over a month ago, a young man brought in a really nice classical guitar for some repair work. He had bought the guitar used on the internet, when he received it he discovered that neck had a lot of bad scratches in the area between the first and fifth frets. He told me that after playing the guitar in that condition, he finally got annoyed with the scratches and contacted the maker of the guitar to see if that person would do the repair work. The maker replied that he was retiring and didn’t have time to do the work. I need to mention that the guitar is finished with shellac, which is applied with the English/French polish technique. The young man then began contacting guitar makers here in New Mexico to see if anyone could do the work, and it turns out, according to him, I am the only maker in New Mexico willing to admit that I finish my guitars with French polish and that I could do the work.
When the young man dropped off the guitar, he asked if I could also work on the fretboard as there were a number of string buzzes. I quoted him a price and that I would start on it in a week or so when the guitar got use to being in a shop with 45% humidity. He had never used a guitar humidifier and the guitar lives in a town where the relative humidity hovers around 10% year around. The guitar was made by a well known maker, it has a Western red cedar top with East Indian rosewood back and sides, ebony fretboard, Spanish cedar neck, etc., etc., and has a nice sound with good sustain.
The next week I sanded out the scratches followed by several sessions of French polish. I let the guitar sit another week to let the shellac harden, then I put strings on it to see what was up. Boy, howdy! The frets were all over the place! Some were high, some were low, I taped off the fretboard and did the usual leveling and re-crowning of the of the frets. I put the strings back on, most of the buzzes were still there! I then filed down the 13th-19th frets that are under the three bass strings hoping that would fix the most severe buzzing, nope that didn’t work either. I emailed the client and told him that I thought the neck was still getting use to being in higher humidity and I would let it sit another week.
A week later, strings still buzzed on frets. I suddenly realized that I hadn’t obeyed the first rule of guitar repair: always check the fretboard with a straight edge before you do any work to the guitar! I did and discovered the neck possessed nearly 3/16ths of an inch up bow under medium tension strings! I contacted the client and told him the situation. I recommended that I pull the original frets, flattened the fret board and install new frets. He agreed. I pulled the frets, leveled the fret board and then for kicks and giggles, I re-strung the guitar before installing the new frets and checked the fretboard with a straight edge. The up bow was still there! That told me a couple of things:
#1. I was stupid for not checking the fretboard with a straight edge (yes, I keep mentioning that fact) when the guitar first came into the shop.
#2. The neck and fretboard woods have lost some tensile strength.
#3. The cost will exceed the quote I gave the owner.
Point #3 is the why I stopped doing repairs on other makers’ guitars. I don’t like surprises that cost more than the estimate.
The easiest solution to the up bow problem was to install new frets and hope that the force of the fret tang barbs will put a back bow into the neck. As expected, that is what happened. Again, I strung up the guitar and found that medium tension strings bring the neck up with a little too much up bow, I was hoping that the string pressure would make the fret board flat. If the string tension had made the fret board flat, I could file the frets to give the proper amount of string relief. This tells me that the neck needs low tensions strings, I am waiting for the strings to arrive by mail as I write this.
When I do put the low tension strings on the guitar I will have to adjust the frets with the strings in place, the neck needs to be under tension to find out whether it is flat, has a back bow or up bow. If I was doing repair work full time I would have to buy the fancy tension jig from StewMac. Just go to StewMac’s website and look at their luthier tools, you’ll see what I’m talking about.
Here is the free advice to aspiring guitar makers. Remember that there are many more things to check on a guitar before you start any repair work then what I have listed, but these are some basic guitar repair tips.
#1. If the repair is beyond your ability, don’t take the job.
#2. If you don’t want to do the repair, don’t take the job.
#3. If you take the job, irregardless of the repair, first thing to do is to look at the fretboard. Consider the fretboard to be the reference point and line for the entire guitar. Ignore this at your own peril.
#3a. The fretboard must be straight, or have the proper amount of “string relief”. Place a straight edge on the fret board to see if the neck is straight, or has the proper amount of relief.
#3b. Check every fret to make sure there are no loose frets.
#3c. Check for low and high frets.
#3d. Check the string slots in the nut to see if they are worn or dirty. Dirty worn slots can cause the strings to buzz.
#3e. Ask the owner if they just switched to another brand of guitar strings. This happened to me once, a client brought in a guitar I made and there were string buzzes every where! After checking the entire fret board and finding nothing wrong, I put on an old set of strings and all the buzzing disappeared!
#3f. Check string action at the 12th fret and inspect the saddle.
Once you have established this baseline reference, then you can further inspect the repair that brought the guitar in for work.
I know you think that you should look at the repair first, in my experience I have learned to start with the fretboard because sometimes a cracked guitar side, or another issue, will bring you back to adjusting the string action.
For all of you guitarists that are reading this post, I implore you to take care of your guitars! Keep them clean, keep them humidified! Every six months or so, take your guitar to a qualified repair person or luthier for a tune up, your guitar will thank you for it! If your guitar gets damaged in any way take it to a qualified repair person or luthier as soon as possible so they can fix it.
There are several books on guitar repair, The Guitar Repair Book, by James Lister is a good place to start, though you should read them all. If you watch a YouTube video on guitar repair, please make sure that that person really is a QUALIFIED REPAIR PERSON, there is so much astoundingly BAD AND SIMPLY WRONG information out there in how-to videos.
