Posted by js on May 26, 2003 at 16:00:42:
If you take your instrument to a repair person, please do not frantically reach over the repair person and depress valves (to avoid vacuum releases) when the repair person is trying to disassemble or reassemble your instrument.
If you are one who buys into the myth that these sudden vacuum releases cause valves to stick, you should keep your belief system within yourself and not allow it to cause you to do annoying nor possibly accident-causing things while a repair person is trying to do their job.
Addressing the myth: If the vacuum release of simply removing slides actually caused damage to valves and/or their casings, what total devastation would surely be caused by simply picking the instrument up off the ground?? Consider also the act of playing and move a slide (for an intonation correction) just before depressing a corresponding valve.
Addressing your observed symptoms: If valves do indeed stick after pulling slides and suddenly releasing the vacuum, the interior of that particular instrument is most certainly filthy , just like the majority of the tubas that I see regularly. Once all of the lime, sludge, and food particles are removed from the tubing knuckles in and around the valve casings, there will no particles to be sucked or blown in between valves and casings when sudden air rushes (vacuum releases) occur, and valves will not stick. If a valve is perfectly clean and yet will stick right after a vacuum release, there is something wrong with the fit of that valve - not caused nor aggravated by vacuum releases.
end of rant