frozen rotor

Yutakatuba · Post by **Yutakatuba** » Mon Jun 05, 2006 4:02 pm

I recently had my horn chem cleaned at a music store. When I got it back 3 out of the 5 valves were frozen. (5th won't go down, 3rd and 4th won't come back up.) They worked on it again, but when I took it back to my house, they are stuck again. Repeated that twice. Then, they relapped, and chem cleaned the valves. It worked again for 2 days, and the 5th valves is stuck again and I can't press it. What is wrong with this horn, and how do I get this fixed? Any help is appreciated.

Yutaka Kono

Rick Denney · Post by **Rick Denney** » Mon Jun 05, 2006 4:47 pm

Yutakatuba wrote:I recently had my horn chem cleaned at a music store. When I got it back 3 out of the 5 valves were frozen. (5th won't go down, 3rd and 4th won't come back up.) They worked on it again, but when I took it back to my house, they are stuck again. Repeated that twice. Then, they relapped, and chem cleaned the valves. It worked again for 2 days, and the 5th valves is stuck again and I can't press it. What is wrong with this horn, and how do I get this fixed? Any help is appreciated.

Yutaka Kono

I had a new rotary tuba that had this problem. It was a buildup of calcium deposits on the valves. When they were moist, they worked okay, but when dry, they would not move.

Did the shop actually remove and clean the valves? If so, the next step is to oil them through the lead pipe with regular valve oil--before and after every playing session. All the calcium deposits must first be removed, and then the rotor surface should be covered in oil perpetually after that. Did they polish off the brown oxide (tarnish) from the rotors and casings? That oxide, once formed and worked in, is actually smoother than raw brass and will help prevent further calcium deposits. Eventually, the oxide will reform and the problem will go away, if it's like the experience I had.

Rick "who wonders why some techs polish off the brown oxide in valve casings and on rotors" Denney

Ed Jones · Post by **Ed Jones** » Mon Jun 05, 2006 5:29 pm

My guess is that when they reassembled the rotors, they did not seat the back plates properly. If the plate is not tapped in evenly all the way around the casing, the rotor will bind. Take the back cap off and using a piece of 3/4" wooden dowel and a rawhide mallet, tap the back plate down so that it is set in firmly all the way around the valve. DO NOT ALLOW THEM TO DO ANY ADDITIONAL LAPPING!

Whenever I have a rotary horn cleaned, I insist on tearing the horn down and reassembling it myself.

windshieldbug · Post by **windshieldbug** » Mon Jun 05, 2006 5:33 pm

Rick Denney wrote:who wonders why some techs polish off the brown oxide in valve casings and on rotors

"I suspect that the techs think the owners expect clean, shiny horns back and may not know, or have already been burned by unknowledgeable owners"

Cameron Gates · Post by **Cameron Gates** » Mon Jun 05, 2006 6:20 pm

Yutakatuba wrote:I recently had my horn chem cleaned at a music store. When I got it back 3 out of the 5 valves were frozen. (5th won't go down, 3rd and 4th won't come back up.) They worked on it again, but when I took it back to my house, they are stuck again. Repeated that twice. Then, they relapped, and chem cleaned the valves. It worked again for 2 days, and the 5th valves is stuck again and I can't press it. What is wrong with this horn, and how do I get this fixed? Any help is appreciated.

Yutaka Kono

I would be interested in knowing what kind of horn this is. Is it a MW?

cjk · Post by **cjk** » Mon Jun 05, 2006 6:47 pm

Ed Jones wrote:My guess is that when they reassembled the rotors, they did not seat the back plates properly. If the plate is not tapped in evenly all the way around the casing, the rotor will bind. Take the back cap off and using a piece of 3/4" wooden dowel and a rawhide mallet, tap the back plate down so that it is set in firmly all the way around the valve. DO NOT ALLOW THEM TO DO ANY ADDITIONAL LAPPING!

Whenever I have a rotary horn cleaned, I insist on tearing the horn down and reassembling it myself.

I agree with the tearing down and reassembling it myself.

When I have had problems like that, it was always the back plates not seating properly. Tapping them back on in a circular motion around the back plate , then removing the screw, popping off the stop arm and giving it a little tap typically lines everything up.

With regards to them lapping your valves. Find a new shop. Your rotors shouldn't need that.

Gator · Post by **Gator** » Mon Jun 05, 2006 7:49 pm

Ed Jones is absolutely right. If you can, tear down and re-assemble the horn yourself, do it!

Along with tapping the back plate, you may also want to get a short 1" piece of PVC irrigation riser to tap the back plate into place. I have found that this will tap the back plate more evenly into place. Also, since the shop has incorrectly lapped your valves, it would be wise to place a lot of lamp oil in your leadpipe to flush out any surplus lapping compound.

tubamirum · Post by **tubamirum** » Tue Jun 06, 2006 7:39 am

When all else fails, check the tubes for damage or whether they have been bumped or pushed so that the casing is distorted. It doesn't take much on some horns. Also , check for small dents on the casing.

Yutakatuba · Post by **Yutakatuba** » Tue Jun 06, 2006 11:39 am

Thanks guys for all your comments. I figured repair guys would do better job than I would, but I guess I should do maintenance on my own horn.

The horn is HB-2, btw. I bought it new back in '89, and I never had a problem with the valves before.

iiipopes · Post by **iiipopes** » Tue Jun 06, 2006 1:46 pm

Uh, your HB-2 isn't one with the metal encased nylon rotors by chance, is it?

Yutakatuba · Post by **Yutakatuba** » Tue Jun 06, 2006 9:47 pm

Yes, it is.

Tubaryan12 · Post by **Tubaryan12** » Tue Jun 06, 2006 10:48 pm

You may want to give this a read:

viewtopic.php?t=11217&highlight=hb2+rotor+problem

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