Winter is the time of year my crack repair business booms. Outdoors the humidity is below 35% . Inside, heating systems dry the air out even more, creating a dangerous environment for delicate musical instruments. There are two things I do to keep humidity a little bit higher during the winter months. In my workshop, where there are likely to be twenty instruments being repaired at any given time, I keep a humidifier going constantly. The brand I use and really like is Bionaire Clean Mist. They are available at most discount department and home center stores.
The instruments I play have personal humidifiers. The humidifiers consist of perforated rubber tubes with a sponges inside. Every time I play my instrument I squeeze the tube. If the sponge is soft that tells me there is still water in it. When the sponge is hard the humidifier needs to be soaked in water. I just run it under the faucet, squeeze out the extra water, towel dry the outside of the rubber tube, and put it back in the instrument.
There are two brands of personal humidifers commonly available: Dampit and Humitron. Both manufacturers make different-sized humidifiers for violins, guitars, and basses, and most music stores stock one or the other of the two brands. If your local store doesn’t have them they are easily ordered. For my money, I like the Humitron. It costs a little less than the Dampit and the rubber tube lasts longer. I only use these guys from late fall to mid spring when the heat is on.
So your house dries out and your favorite fiddle gets a crack. It’s not the end of the world. Most cracks will close when the air around them gets more humid.
To keep a crack from opening again, the crack should be glued. Small wood cleats are glued to the inside of the crack to stabilize it, and the finish along the crack is touched up to seal the crack. Cracks that do not close require the addition of a piece of wood. The luthier’s term for that new wood is “spline.”
Putting in a spline first requires that the crack be evened out. A knife or razor saw are used to make the open crack even from end to end. Normally the crack is not opened any more than 1/32″. The spline is then made of matching wood and scraped to fit the widened crack perfectly. After fitting, the spline is glued in the crack, cleats are glued to the inside, and the finish touched up.
Crack repairs, as with all other complex repairs, should not be tackled by the inexperienced. If you are not sure what the repair requires, take your instrument to an experienced professional. Repair persons know it’s easier to fix it right the first time than to undo a bad job.
Low humidity is not the only cause of cracks. Personal experience has taught me that walking into a bench vise with a guitar during a workshop jam session or leaving your fiddle on edge on top of a picnic table during a wind storm and watching it blow off are real good ways to crack your instrument.
But, if you are careful and don’t let your instrument dry out, the only cracks you’ll experience are wisecracks from the musicians with whom you jam.
Bob Smakula is a musician and resident of Randolph County, WV. He is the proprietor of Smakula Fretted Instruments specializing in the restoration and sales of vintage stringed instruments
Contact Bob at firstname.lastname@example.org