For the third and final post in this brief series on low brass instrument lubrication and maintenance, let us turn to the subject of piston valves. Given the simplicity of piston valve design and maintenance compared to trombone slides and rotary valves, devoting an entire week’s post to the subject might seem extraneous, and perhaps it is. Nevertheless, since a primary purpose of this blog is to provide a space for me to work out in writing ideas and themes to develop in later published writing or instructional materials, I want to go ahead and include this discussion for the sake of completeness. As I mentioned a couple of weeks ago, I plan to take the materials from these three posts and use them to augment the already copious instructional and reference materials I provide to my studio and methods students.
Regularly Needed Items
- Valve casing brush.
- Cleaning snake (vinyl or rubber-coated).
- Dishwashing detergent.
Lubrication (and Cleaning) Instructions
Most of the time, lubrication should be fairly simple. Unscrew the top valve cap, remove the valve from its casing just a bit, apply a liberal amount of valve oil to the piston itself, and then replace, taking care that the valve guide is seated in its correct position. Distribute the oil by operating the valve normally. Repeat this process for each valve.
Every couple of weeks or so it is helpful to swab out the valve casings to make sure they are free from grime and debris. For this, remove all of the pistons, bottom caps, and springs, taking care to keep the “parts” for each valve together. Form a clean paper towel into a thin roll and use it to scrub the sides of each casing. Repeat for each valve. When reassembling, take care to place the correct piston into each casing, or else the instrument will not function correctly. If you cannot remember “which is which,” most makers lightly etch the number of each valve in an inconspicuous place (usually the top of the piston).
If the instrument is particularly grimy, you might consider “giving it a bath,” disassembling all the valves, removing all of the tuning slides, and submerging it in lukewarm, soapy water. Specifically regarding the piston valves in this situation, you can use a valve casing brush to lightly scrub the insides of the casings to remove any stubborn debris that has been loosened by the water. Food particles, etc. entering the instrument through the leadpipe can cause problems particularly for the first valve; running a cleaning snake through the leadpipe during the “bath” can remove much of this. Afterwards, make sure the first valve casing is clean before reassembling the instrument, and never “snake out” the leadpipe while the valves are assembled.
Once again, when reassembling the instrument be sure to insert the correct piston into each casing.
When Cleaning and Oiling Isn’t Enough
If your valves still do not work well after taking these steps, it may need a trip to the repair shop for a professional chemical or ultrasonic cleaning, or it may need to have the valve guides, springs, or corks and felts replaced.
Valve guides are small plastic, rubber, and or metal pieces that “stick out” a bit from the top of each piston and fit into a corresponding “track” in the casing. The purpose of these is to keep the valves in the correct horizontal alignment—if they were allowed to spin in the casing, the instrument would be impossible to play as the ports would continually come into and out of alignment. When a valve guide wears down the valve might begin to stick as the guide slips out of its track, or it could begin to spin freely if the guide wears out completely. Neither of these is desirable, of course. Valve guides are considered a “normal wear” item and are easily replaced by a technician, though most players and teachers can also do so themselves. I recommend purchasing a few extra sets of valve guides for your instrument and keeping them on hand so that they can be replaced at a moment’s notice without the time and expense of a trip to the repair shop.
Springs are another item that should be expected to “wear out” from time to time, whether from becoming overstretched, too compressed, or simply dirty and corroded. As is the case with valve guides, I recommend keeping a few extra sets of springs on hand at all times. Regardless of the make and model of instrument, I use and recommend Yamaha springs whenever possible, as they have a thin coating that reduces noise a bit. I cannot promise that the Yamaha springs will work in *every* instrument, so do understand that if you try them that they might not work. As is the case with valve guides, these normally have to purchased from your repair technician.
Finally, the felts and corks that maintain the valve’s vertical alignment also degrade over time, with leakiness, stuffiness, or poor response being an indicator (in addition to visual examination) that it is time for the felts and corks to be replaced. While it is possible to purchase these on your own (at least for some makes and models), I recommend having these replaced by your repair technician in order to maintain the most precise alignment. This is a routine service that is performed relatively quickly and inexpensively in most cases.
Happily, piston valve lubrication and maintenance is almost always a simple affair. Keeping the valves clean and well-lubricated at all times (piston valve instruments should never be left “dry” if they are not going to be used for a while) will do much to maintain the instrument in good working order, apart from routine maintenance and parts replacement as mentioned above.