In general, clarinets don’t require a lot of maintenance because most of the keys are closed most of the time. The pads that go out of adjustment are the ones that are open when the instrument is in storage: on the upper stack that’s the D/A key; on the lower stack that’s the ring key, F/C, and E/B. If the pads were correctly installed with a sufficient amount of glue, all that’s necessary is to heat the glue and nudge the pad into the correct position.
Here are some things to check for on a clarinet:
As with all woodwinds, keys should ONLY go up and down. If they also move side to side (or “wiggle around”), the excess motion has to be corrected before anything else is done.
ARE THE JOINTS FITTING TOGETHER WITHOUT A GAP? If a ring is too wide it will extend past the end of the wood and prevent the joints from fitting completely together. That creates a gap in the bore, which can cause turbulence in the air column. The simple solution is to remove the ring, file or sand the inside edge to reduce the width (it’s easier to remove metal from the “outside” edge, but that removes the finish). When the band is the proper width the instrument should fit together without a gap in the bore.
IS THE BORE EXACTLY THE SAME WHERE THE SECTIONS FIT TOGETHER? Where the barrel fits onto the upper joint, and where the upper and lower joints fit together, the bore should be exactly the same. A “step” between the sections (one side is smaller than the other) can cause turbulence in the air column. This can be corrected by removing a very very small amount of wood from the “small” side so it matched the “large” side.
A gap or step where the joints fit together can make some notes “stuffy” or “fuzzy”, most particularly the throat Bb, the middle Eb/Bb, and the middle C#/G#. Correcting these problems can also reduce the amount of “resistants” (how hard it is to blow into the instrument), and make the tone fuller and more resonant.
NEW STYLE BUFFET CLARINETS WITH THE PLASTIC FITTING ON THE LEFT HAND B/E AND C#/F#: The newer Buffets use a plastic connector on the left hand keys. When new those do not have any goldbeaters skin to reduce key noise, but as they wear down they can start to “click”. That can be corrected simply by adding some goldbeaters skin, just like on other clarinets. Occasionally one of those connectors will break. After doing some research I found a carbon fiber replacement that’s made by Wesley Rice (www.clarinet-repairs.com). You can order them directly from Wesley, but he was kind enough to sell me a handful so I have them on hand.
INTERESTING FACT! Goldbeaters skin (the material used to quiet the mechanism on the lower stack left hand keys) is a type of parchment. It’s called “goldbeaters skin” because it’s used to make gold leaf, those very very very thin sheets of gold used on picture frames and other places where a layer of real gold is desired. The procedure is to alternate a sheet of parchment with a sheet of gold (up to 120 layers thick). The block is bound together and then hammered with a very heavy mallet. The final sheet of hammered gold can be 4/1,000,000 of an inch thick!