Valves need very frequent oiling

[Matt Good]

I am not a repair tech but I own several tubas that have MW piston valve sets. You may be using an oil that is too thin. I have had success with mixing Ultrapure Lamp Oil with a very small amount of 30W Mobile One. You may also want to try Hetman #3. Just my $.02.

-Matt

[TheGoyWonder]

maybe the cylinders need some controlled wear to smooth out. (car metaphor)

[PaulMaybery]

When I was a kid, I had a cheep stencil sousaphone, it looked like basically a Conn.
Okay, the point was the 1st v always had a sticky spot that reared its head shortly after oiling. The valves were well broken in but no sort of lubricant would make much difference. Even an old brand, called "Willwork" that had cold cream in it to help with the seal on old and worn valves. Back then I had no access to a fine technician so I learned to live with it. Recently I sold the horn which had layed in the basement for 40 years. In the meantime I had become my own best technician (that was in my own mind) I reassessed the situation and said to myself "what the heck" and loaded the piston up with brasso and began the lapping process. Voila, smooth as silk and no little hang-up. Some how something, it may have been pressure from a tuning slide or a brace, but it took lapping to smooth down that microscopic bump. In that case it was not foreign matter but actually a physical issue. And... more than likely the problem may have been with the casing, not the piston.

[Lee Stofer]

I'd just add that I'd be suspicious of the original fitting of the valves in both of the aforementioned instruments. To rid yourself of continuing annoyance, I'd suggest that the pistons be carefully lapped. The owner or repairman should also check by hand to see if there is any kind of rough spot or burr at the intersection of the valve casing and the port. The nylon valve guides can develop a small plastic burr that is especially troublesome, but these can be carefully shaved-off with a sharp blade, and will make quite an improvement in the piston performance.

Whenever I've serviced tubas that have been lubricated with Ultrapure Lamp Oil, the have had unique-looking white deposits (looks like white cheese) inside, and although it has never been difficult to clean out, the sheer volume of accumulation has to have a detrimental effect on the performance of the instrument. I suppose that if you use lamp oil, and clean the instrument twice a month or more, it would not have accumulation issues.

Joe Hetman's philosophy is that you should use the heaviest viscosity valve oil possible and still have acceptable action (feel). His #1 Light piston is for soprano brass instruments only, and only those with tight tolerances. The #2 Piston Oil has a comparable viscosity to the standard petroleum distillates oils, and is what I use most of the time, for most piston instruments. For instruments with looser tolerances because of age or manufacturing process, I use the Hetman #3 Classic Piston. The #1 Light Piston, and Al Cass, are not a good idea for either tuba or euphonium. The automotive equivalent of using light piston oil on a tuba would be putting SAE 5W-20 motor oil in a Peterbilt, or a diesel locomotive. We play the heavy equipment, and need to apply proper protection to the valves.

Well, back to the workbench!