Perhaps the most misunderstood problem with wooden clarinets is cracking. We have seen and repaired thousands of cracks during our 40 plus years in the business. A simple conclusion will make it very clear that the reasons are not the age of the instrument or lack of proper treatment from the manufacturer. Cracks always appear at the same spot on the instruments. The majority of clarinets crack at the 4 top tone holes or the register tube. Oboes crack at the trill tone holes or other tone holes. They crack because of the physical forces and the exposure of extreme humidity, produced when the instruments are played. If the reason for the cracks were manufacturer defects, we would see cracks in all other places. They hardly ever occur at lower joints or bells.
It is impossible to guarantee that the wood will not crack. Despite its great density, grenadilla, like any other wood, absorbs and releases moisture. It is hygroscopic. Moisture will be absorbed from the players breath and from the resulting condensation in the tube, as well as from the atmosphere itself. The humidity inside the instrument will be close to 100% when played. When moisture is absorbed or released too rapidly or unevenly, internal stresses are set up within the wood. If these stresses are too great the instrument can crack.
If that happens the crack can be nicely repaired without reducing the quality of the instrument. Don't wax or oil the wood when that happens. The tone hole needs to be replaced. If this is done correctly everything will be fine.
Don't get the instrument pinned under any circumstances!!! read more .
Unfortunately, this obsolete and destructive technique can still be found.