Front Action Pistons - An Indelicate Question?

[bigtubby]

The tubas I've been playing are all the standard Cerveny (and the German copies thereof) design. All acoustical considerations aside, this layout is excellent at what my civil engineering clients call 'drainage' - the condensation all runs down to the main tuning slide circuit where it is easily evacuated in a controlled manner.

Recently I acquired an old King 4V raincatcher.

Playability? Voice and timbre? Wonderful! Intonation? Pretty acceptable.

Drainage? Not so much. Condensation collects in the bottom of the valve casings so that when the instrument becomes somewhat horizontal (as in removing it) water pours out of the bottom caps.

I've considered drilling and tapping 1/16" NPT holes near the bottoms of the casings, knocking the check valves out of zerk fittings and making a plastic fuel line manifold ...

What do those of you who use front action piston instruments do about this?

[Dan Schultz]

..... Condensation collects in the bottom of the valve casings so that when the instrument becomes somewhat horizontal (as in removing it) water pours out of the bottom caps.
....
What do those of you who use front action piston instruments do about this?

I've only had a problem with excessive moisture on horns that had excessive clearances in the pistons. My 48K was a real mess to play until I sent the valve section to Anderson.

[bigtubby]

..... Condensation collects in the bottom of the valve casings so that when the instrument becomes somewhat horizontal (as in removing it) water pours out of the bottom caps.
....
What do those of you who use front action piston instruments do about this?

I've only had a problem with excessive moisture on horns that had excessive clearances in the pistons. My 48K was a real mess to play until I sent the valve section to Anderson.

This horn was advertised as "near mint" ... and it is actually excellent+ in my book. But the pistons are good, no brass showing through at all and acceptable "pop" a couple of seconds after slide push/pull. But no condesation should be finding its way into the bottoms?

The condensation collecting in the casings doesn't affect playability (no gurgle or whatever) but is there when the casings are vertical. Maybe I drool too much :\

[bigtubby]

Yeah, what Dan said. Consider that to be akin to blowback from bad rings in a car engine. It is leaking in the piston casings. Try a heavier oil to see if that helps the problem. If so then that is the issue. If not, it still *could* be that, but it is not as bad as I am thinking it might be.

York had a nifty device on their sousaphones. I have a piston set with them installed. When I get the Anderson's to rebuild this piston set they will probably be unnecessary, but I am keeping them because they are so cool!

The bottom of the bottom valve cap is pitched downwards like a drain. The hole is HUGE and holds a small piston-type device with an air vent hole in the center that is not as big as normal but vents the valve well enough. You push this piston in and the water drains around the bottom. You let go and all water is trapped in the cap while it retains its crucial venting ability. Very trick!

I can post photos if you like. You will not be able to copy it easily, but photos might give you ideas on how to address this if you choose to not get your piston set rebuilt. (Intonation will probably improve if the valves are indeed leaking enough to bleed condensate from inside the bore of the horn.)

Here is a very low res shot. I can give you internal and external shots with more detail, as well as an exploded view to see all the parts if you like.

Thank you!

Suggestion for heavier oil would be appreciated for testing purposes.

A couple of questions about this:
1. Should there be no condensation at all in the bottom of the casings?
2, These "water keys" in the bottom caps basically allow for better disposal? (I can infer the parts from your photos thank you)

This thing plays _really_ well. If the valves are leaky I think that it will be amazing with better clearances in the valve block.

[bububassboner]

A different reason for this drainage.

If the valves are vented, water will drain out of the bottom at times. This mainly happens when I lay the horn flat on my lap (like to oil the valves) not much you can do to stop it. Drain the water before laying the horn down.

[ppalan]

What is the thickest oil available for tuba valves? I have and old horn that might benefit from this but don't want to buy dozens of different oils to experiment.
Thanks
Pete

[Donn]

It's easy and economical to mix your own. Get a big bottle of lamp oil, and some motor oil. I'm not kidding, this will work fine. You don't need much motor oil, and it can be whatever weight you want - 10W-40, 30W, whatever you've got. When I change the oil in a motor vehicle, I might save the bottle and coax out the remaining drops for valve oil. You really don't need very much, unless you want some really thick oil.

As an experimental medium, that won't leave you any the wiser about what grade of commercial valve oil you'd want, but it will give you some idea what happens with really thick oil. You can get it so thick that the valves barely move, or as light as plain lamp oil (very light.)

[iiipopes]

The best oil mix for piston valves that are worn, but still playable, is to take a good clear valve oil, like Roche-Thomas, put an ounce in a smaller individual bottle, and add a drop at a time of pharmaceutical grade mineral oil until the valves don't leak, but don't slow down, either. Cheaper and better than Hetmans or Yammy.

[OldBandsman]

I have a 100 year old King helicon with valves that vent down onto my shirt. Wife not happy about oil stains on shirt.
I wrap some towling around the bottom of the valves. Doesn't look great held in place with green velcro from the lettuce heads, but does the job nicely.
John Roberts