Stay in Tune vol #119
By Luthier Patrick Podpadec
It's hard to believe that the summer is almost gone. My son will be going back to school in a month and we haven't finished our quota for camping yet. We have to go at least 3 more times. Even though time is flying at a ridiculous pace everything else seems to be going quite well . the garden is thriving nicely , the home projects are slowly getting finished and the work and shop jobs just keep on coming. I feel blessed to have all of the friends, family and opportunities that greet me every day.
As usual, I find myself juggling many different projects and some times it feels like not much is getting accomplished. I have to take a look around and look at what has been done to evaluate my progress. One thing that I have finally been able to cross off my list is a repair that has been proving to be a bit more challenging than I had originally conceived it to be. A cello was brought to me with a bad crack in the upper bout . Actually it was two cracks. It looked as though something had hit the side quite hard but not enough to put an actual hole in it. I first thought of removing the back and re-alining the sides together and adding cleats to the crack to stabilize it. Although not a bad idea, it could of opened up a can of worms that could of turned out to be a nightmare. Removing the back off of any instrument can be very challenging. There are many things that can go wrong along the way. It's easy to do damage to the ribs (sides) and trying to re- attach it back in the perfect position can be very daunting. Often the sides of an instrument will have tendency to "splay out" or loose it's original shape once the back or top has been removed, Getting it back on perfectly can be tough. Often times you must rig up some sort of temporary form to be able to retain the shape. So not only are you repairing a crack in the side you are now having to perform a whole other difficult procedure that has nothing to do with the crack in the side. I decided, without too much trouble to abandon the idea of removing the back. The next step was to figure out how I was going to align the wood and be able to glue and reinforce it with cleats at the same time. Take in consideration that there is very little access to the inside because of "f " holes. There is no clamp that I know of that can fit in the oddly shaped "f" hole and be able to clamp something on the inside of a cello. I couldn't even get a stick or anything to wedge the two sides of the crack back together. My problem was that the crack was pushed in , not out, and I had to find a way to "pull" it back together. It's going to be hard to explain this procedure without pictures but here is what I did:
I drilled a couple, three very small holes along the center of each crack. I was able to fish a small guitar string (about a .014) into the hole. I wanted to use the balled end of the string to pull a cleat from the inside to align and glue the crack at the same time. There was no way to fish the string in from the inside , so I was able to get the string in the cello from the outside and fish it up thru the "f" hole and grabbed on to it. I then took a short (4" piece) of .014 string that had a balled end on it and soldered it to the string that was fish inside from the outside. I made a small caul and spruce patch (cleat) and drilled a small hole through them. l had to make sure that they were small enough to fit back thru the "f" hole and also had to put them on the balled end of the string before I soldered them together. I then was able to pull them back through the hole that I drilled in the center of the crack and re-align the sides of the crack back together. I then made a very small base and attached a tuning machine to it. I was able to tighten up the string which pulled the cleat and the clamping caul from the inside and glued it all in one step. Of course it took a few "dry runs" to be able to make sure that it was all gonna go the way I had hoped. One other problem that I had to solve was that one of the cracks was right next to a lining on the side so that when I pulled my cleat from the inside, The thickness of the lining prevented me from aligning the sides if the crack properly. I had to add a small "ledge" to the cleat so that it would span the lining and the side at the same time, I know that it is difficult to visualize through my description, but believe me it was just as difficult to figure it out and successfully make it work. I didn't record the amount of time that it took, but it's safe to say that I didn't make any money on that repair. The knowledge and skill that I developed from it was enough pay for me. Of course now that the crack is now glued, cleated and aligned properly and very secure it is time to try to hide those awful holes that I put in the sides. Although they were small they still looked to me to be about the size of a dime. A few small chips of colored varnished was lost on the process of the repair so it was necessary to mix some color to match the existing side. I filled the holes and cracked edges with a small amount of colored epoxy and was able to sand them flush and the whole repair came out very nice. From 10 feet away you can hardly see it (ha, ha). Of course when a repair like this comes about it's always important to warn the customer of the possibility that the repair is not going to be invisible, the important thing is that the crack has been glued properly, it's secure and that there will be no possibility of it buzzing from the vibration of the bow being pulled across the strings.
Well, I think the lesson today is "Don't put a crack in the side of your cello"! but if you do , at least you know how to fix it now, or you can still always bring it to me and I will be glad to fix it for you . Thanks Again for reading the Voice and please "Stay in Tune"
Patrick from Liam Guitars/ Wood-n-Strings