Over time, as you play your clarinet, the mechanisms will shift slightly due to use. This is normal, but it can cause problems as you continue to play, particularly if something shifts far enough that it creates an air leak. When leaks happen, we tend to squeak or a note simply won’t come out at all, especially in the fundamental register (lower notes of the clarinet, without the register key). Thankfully, these small misalignments of keys, screws, etc. are fixable, often with minimal tools and materials. There are cases, however, where you’re likely to do more damage trying to fix something yourself and you should take it to a reputable repair person.
Air leaks often happen as keys are bent slightly out of alignment over time. They can also happen if a pad is damaged, if a key breaks, or if a screw is loose, bent, out of tension, or broken. To determine if there is an air leak, take the upper or lower joint—whichever you suspect may have the problem—and close the bottom end with the heel of your hand, cover the tone holes as you would while playing, and try to create suction by sucking on the top end of the joint. If you can get a good sense of suction, the chance that there is an air leak is much lower. If you can’t create suction, there is likely a leak in that joint somewhere. To pinpoint where the leak is, blow into the bore with your fingers closing all the keys, gently and then very strongly. This should force air out through the leak, and you will hear it escaping.
Once you have a good idea of where the leak is, start checking for loose screws. Loose screws are the easiest thing to fix because they simply need to be tightened back into place (and this is why many clarinetists carry a small screwdriver in their cases!). It is possible to over-tighten a screw, so be careful to check that the key still moves up and down freely. Tightening screws can also adjust the height of the keys, another means of solving an air leak. If a spring is de-sprung (does not have tension) or is bent or broken, you’ll need to visit a repair shop to have it replaced, as springs are relatively fragile and are easy to break without the proper tools.
If a key is bent, it will prevent the pad from sitting properly over the tone hole. If you have leather pads, you can moisten the pad (using water or saliva) and then press the key firmly on the hole; this will re-align the pad to the tone hole if the key is only slightly bent. You can also try to bend the key back into position by gently pulling it in the opposite direction of the bend; if it is more than a slight bend, this is not recommended, and the clarinet needs to be taken in for repair or even replacement of the key.
It’s also a good idea to check that the tenon corks all fit into the joints tightly. If a cork is very worn and flattened, the two joints may not fit together snugly, and air may escape; this may also happen if a cork rips or tears. In a pinch, a piece of paper can be cut down and wrapped around the tenon tightly to tighten the connection for a performance, and then the cork must be replaced.
These are basic solutions to the common problem of air leaks on a clarinet. If you find that leakages persist, it’s best to visit a repair person. Additionally, there are many websites that teach you how to do simple repairs such as replacing pads and corks. Two great ones can be found here and here.
