TubeNet

Is it possible to vent a piston valve? If so, how is it done? What are the advantages of venting a valve? Does it adversely affect the sound or pitch of the tuba? Any info will be much appreciated.

Thanks

Since no one has addressed this issue, I will.
First of all, I will say that if you've never done this yourself, don't do it now.. IF you drill in the wrong spot, you'll be looking for someone that can fill the hole AND smooth it properly. Could be big bucks.... Better to take it to a repairman that's done it before.
Now, that we're past the warnings....
If you look at your piston you will see a stain, it will be round and match where one of the ports match up, but only 1/2 the time. This stain will be (if memory serves) under a single port in the piston.
You need to drill there.... You will need to counter sink the hole as well to make sure there are no burrs. I usually use a deburring tool as well as 600 grit wet dry paper, AND polish the piston. You must not have ANY impefections.
So, If you can picture this:
when the piston is in the up position, the now stain, and hole that was just drilled, is in the middle of the port in the casing. No air is passing through this port in the up position, but it's allowed to equalize pressure in the casing. In the down position that same drilled hole is against the wall of the casing. Hope this is all clear.
There are considerable benefits to venting, it frees the over all feel of the horn and it smooths the sound from note to note.
(ie. c,d,e,f) on a CC tuba. It will take away the pop between the notes.
Again, I will stress taking the horn to someone that knows what they're doing.... Horns and pistons aren't cheap these days...
Good luck,
Alan Baer

Please forgive an ignorant question that has probably been asked 1746 times before, but....

is it possible to vent rotary valves? If so, is there as much of a difference in the horn's feel post-venting?

Kyle

Same benefits.....
need VERY long bit to drill between the ports it the casing...
Again same warnings.....
Alan Baer

I haven't been on here long enough to know what the conventional wisdom of the BBS is for this, so here goes nothing...

Before you consider having anything vented (piston or rotor) you might consider having something done to manipulate the main tuning slide instead.

Advantages:
- no harder to play than a trombone...
- allows any note to be "shaded", including open notes, without needing the use of alternate fingerings
- allows for tuning changes if needed while playing without dropping the horn
- does not require any more pull than would otherwise be needed
- keeps you focused on one slide instead of 2/3/4
- needs as little or as much attention as you would for valve slides
- can help develop the ear in students
- no "popping" because always vented (not just sometimes... )

I wouldn't have played my big symphony horn without it!...

It's been several years since I've taken a valve to a repair shop to have it vented, but as I recall, it is a pretty inexpensive job. Is that still the case?

I can't imagine ANY motivation to try this job as a "do-it-yourself" project. Vented valves, particularly the first valve, provides a benefit that probably is worth the expense. The risks of damaging your valve from trying it yourself, though, probably outweigh the benefit of having vented valves.

I believe that either (1) paying someone to vent your valves; or (2) leaving your valves un-vented, are both better options than trying it yourself.

Uncle Buck wrote:It's been several years since I've taken a valve to a repair shop to have it vented, but as I recall, it is a pretty inexpensive job. Is that still the case?

...
I believe that either (1) paying someone to vent your valves; or (2) leaving your valves un-vented, are both better options than trying it yourself.

Matt Walters charged me $40 to vent the valves on my York Master. He said the first one was $25, so it made sense to do them all.

I vented my own valves on my Yamaha 621. Instead of drilling a hole, which required a jig arrangement I didn't have, I ground a slot lengthwise through the port using a Dremel cutoff wheel, well chamfered with a Swiss file. It has worked fine for the intervening 13 or 14 years or so. Cutting that small slot was very much less risky than drilling a hole.

Rick "who thinks risk management include knowing one's limitations of skill and equipment--and knowing how to work around those limitations" Denney

DO NOT TRY THIS AT HOME (because I didn't do mine -- Lee Stofer did).

IIRC (and I could be wrong), Lee drilled upwards from the bottom of my piston valve and into the lower tube of the valve body. I don't own that horn any more, and my memory may be incorrect. But would that strategy accomplish the same thing? (Quick -- somebody go check!)

Thanks,

Steve Inman wrote:IIRC (and I could be wrong), Lee drilled upwards from the bottom of my piston valve and into the lower tube of the valve body. I don't own that horn any more, and my memory may be incorrect. But would that strategy accomplish the same thing? (Quick -- somebody go check!)

I don't see how that would work. The passages in the valve are there only for the purpose of moving air and sound, and drilling a hole in any of them will create a leak either with the valve up or down.

Drilling the shell of the piston valve in the part that blocks off the valve tubing when the valve is up is the only way to vent the valve tubing. There are no valve passages exposed to the valve tubing when the valve is up.

Rick "thinking Steve misunderstood what Lee was doing" Denney

I know this is an ancient thread, but since I was googling this exact question thought I would add some info...

When you drill your hole be VERY careful not to go beyond the piston wall. It's easy to accidentally punch a hole through the port tubing (though not hard to fix if you're handy with solder). Also Rick is exactly right in that having a hole in the port tubing won't behave the way you want - it introduces a leak which will make your horn unplayable. And yes, I learned this the hard way...

That said, it's not hard to do but not something I would suggest unless you have drilled stainless steel before (if your valves are stainless).