HB2 valve repair question

[JB]

HB2 valve repair question.

This question was buried in a recent poll about Hirsbrunner tubas, and didn’t get a response. I’ll try again, here “in the open.â€

[Chuck(G)]

I'm not an HB2 owner, but I've heard of the problem with this model.

I wonder if you have one of the models with the lightweight composite rotors, rather than the solid brass ones. If that's the case, short of replacing the rotors, you're probably stuck with the situation. The problem is that the rotors expand at a different rate than the brass casings and will jam at higher temperatures.

Have you written Peter Hirsbrunner to see if he has some suggestions?

http://www.hirsbrunner.com/lang/engl/co ... ntact.html

[cjk]

If memory serves, the Hirsbrunner solution is to heat the horn up and lap the valves.

I've heard some folks that swear by Blue Juice on the composite rotors. It's a cheap experiment if you haven't already tried it.


Christian

[Mudman]

A local player built a horn using a composite HB valve-set. The only way he could get his horn to work was to run cold water through the valves, into what looked like a colostamy bag attached to the bottom of his tuba. During rehearsals and performances, between movements, he would pour water through his tuba. Not a very elegant solution, but I guess it worked.

[JB]

I'm a piston person, so forgive my ignorance...

With all of these problems and tempature sensitivity, why would someone own one of these horns? Sure, given that they probably have the classic Hirs sound, but why not trade it in for another Hirs?...

Thanks for your reply. I thought I'd jump in and answer a couple of your questions. Very good questions, actually.

I bought the horn while still a student in grad school, and at the time was completely unaware of the problem. It didn't surface 'til a few years after I had left school. (Not many "hot temperature" gigs while studying, I guess.) The first few times this happened I thought that perhaps it was a bit of dirt or grime that caused the problem. It took a few repetitions until I made the connection between the higher than normal temperature and the valves seizing.

This horn was a gem amongst gems; a number of major "heavy-weights" were very kind and helped select this specific instrument from amongst a number of HBs. Sound and playing characteristics are superb.

For my own sound and tastes, and having tried a number along the way, I prefer rotors to pistons. (One of my other horns is piston, in fact.)

I'd love to be in the financial position to trade upward (and I'm sure, with some patience I could find another HB that felt/played/sounded similar), but at this point in life, with family and the accompanying number of obligations, I just can't see being able to do so for some time yet. Wish it were otherwise, but not probable in the next while.

So, given these varied reasons, I was hoping that there might be a more affordable (i.e. less drastic) fix that would tide me over until sometime down the road when, perhaps then, I could look at another instrument.

Hope the added insight answers the questions.

Thanks.

[JB]

Thanks to all for you responses thus far. Hopefully others will continue to chime in.

I wonder if you have one of the models with the lightweight composite rotors, rather than the solid brass ones. If that's the case, short of replacing the rotors, you're probably stuck with the situation. The problem is that the rotors expand at a different rate than the brass casings and will jam at higher temperatures.

Have you written Peter Hirsbrunner to see if he has some suggestions?

Yes Chuck(G), it is one one with the lightweight composite rotors. And, following your suggestion, I have written to Mr Hirsbrunner to see what remedy he can suggest. I shall post the result once I have a response.

As a repair tech who normally will work on rotors, I will not mess with these particular valves for the following reasons.

- The manufacturer seems to advocate making the valves leakier (lapping them well beyond factory lapping - though the valves are at least 20 years old) to solve the problem. To me, this route seems to be a solution that a "hack" would consider. The only "real" solution is to replace the valves with valves that do not expand and contract. In other words: If the valves are "nice and tight" when they are warm, what are they when they are cold?" answer: L _ _ _ Y

- Being constructed of various materials that are not all originally afixed to the valve stems, there is a considerable risk of further damage to these rotors during lapping - particularly if done at higher temperatures (which increases the risks of seizing and snapping).

- It ain't mine.

The "rub" (pun intended) here is that the rotary HB 4/4 is arguably the best of all of their 4/4's...Unfortunately, there are a ton of them out there with dysfunctional valves.

And Bloke, I appreciate the expertise-based insight. Might I ask a question of you? If this were your horn, and you found yourself in circumstances similar to what I described above in my response to cc_tuba_guy (a.k.a. Jay Young), what would you do?

Any others out there who wish to add their $0.02 worth?
What about those of you who own one of these HB instruments – what say you?


Thanks to all.

[JB]

And Bloke, I appreciate the expertise-based insight. Might I ask a question of you? If this were your horn, and you found yourself in circumstances similar to what I described above in my response to cc_tuba_guy (a.k.a. Jay Young), what would you do?

uhh...Maybe rather than trying to fix the valves before you sell your tuba, (since you want to "trade up" anyway) see if one of the five or so "tuba stores" located in the U.S. might be interested in trading it in on something they have that you like better. Then let them worry about the valves.

Your advice makes sense -- and is appreciated. One small wrinkle to toss into the mix. Recall the part written above that went something like...

I'd love to be in the financial position to trade upward (and I'm sure, with some patience I could find another HB that felt/played/sounded similar), but at this point in life, with family and the accompanying number of obligations, I just can't see being able to do so for some time yet. Wish it were otherwise, but not probable in the next while.

So, given these varied reasons, I was hoping that there might be a more affordable (i.e. less drastic) fix that would tide me over until sometime down the road when, perhaps then, I could look at another instrument.

With this in mind, what would you suggest as "plan B?" (Aside from "drop back 5 yards and punt...")

Again, with thanks.