Sticking rotary valves?

[Peach]

In your experience, roughly how long does it take a rotary valve to seize if left unplayed?
I seem to remember anything over 2 months isn't ideal...!
Any tips on minimising seizing and also getting your rotors back up to speed after some time off?
=)

[PaulMaybery]

I hesitate to write this, BUT... (How many times have I srewed things up?)

Seisure usually stems from not only drying out, but also lime deposits or some other type of corrosion. A repair tech should perform a chem clean to remove the scale or calculus. This has been covered in other posts but suffice it to say, this can be treated at home. Somehow or other the deposits need to be removed. An acid such as in vinegar is a mild 'home' solution to soak the rotors in. The interiors of the casings can be swabbed liberally.

I've used metal polishes with light abrasives such as Brasso or Noxon. But this I only did once on a Chinese import with tons of crud on the rotor, spindle bearings and bearing plates, coupled with rather gently polishing with a toothbrush. I would not recommend doing this over and over. You can also put just a little on the spindle bearing and back plate bearing to just finely lap those contact points smooth, by turning the rotor with the compound. When you replace the bearing plate snuggly, the rotor should still turn. If you know it is flat on and clean, and it still binds, it may still need more cleaning or lapping. If there has been some corrosion, and you can see it, (usually greenish) the surface of the metal becomes etched and is somewhat raised. This can cause binding if not lapped smooth. Ideally this should not have to happen, but it does. When the metal is dry, you can feel the rough spots with the soft ball of your finger tip.

I can't emphasise how important it is to rinse and flush and repeat several times. You will also want to clean things with some valve oil as most polishes have an oil base and are a bit stuborn to clean with just warm water and a rag.

The clean rotors should spin freely when assembled and oiled. While it seems as they do work when simply "just wet," plain water with lime deposits will begin the process all over again. Oil inside the rotars by pouring valve oil either in the lead pipe or a convenient tuning slide. Oil in the lead pipe is not a bad idea either. Get oil on the spindle too. There are needle nose oilers for doing just that.

If you have an Asian import, chances are it is factory crud that needs to be cleaned. If its a gool ol' european import, it is likely deposits accumulated from good honest playing.

Once you get the asian crud out, things will probably work fine as long as you keep oiling periodically. Asian crud is often black.

A chem clean is not cheap, but a good horn isn't either, and it is nice if it can keeping working like a new one for a long, long time. Pretty much just like car maintenance.

If it is a pretty new and fancy looking job, I would take it to a shop and not risk compromising the valves. An older POS tuba, I would not hesitate to do myself. Good luck and I hope you don't learn the wrong things the hard way.

[ScottM]

I have discovered that after playing, if i know i won't be playing the horn for a while, I oil the shafts top and bottom, and also get some oil into the valves themselves to help avoid this issue.
ScottM

[Peach]

Thanks chaps.
Sounds rather like pistons, except if/when rotors DO get stuck, a trip to my tech is a bit more likely.

[bort]

In a case, it takes much longer than out of a case. I've been to Dillon or BBC before, and the horns just sit out and the heat/AC dried things out. I've gone months between playing horns before, when I had an F and a CC. Could only play one at a time, so one of them just sat out. I honestly don't remember anything seizing up.

And Mark.is absolutely right, don't free it by forcing the lever down. Grab the part with your fingers and gently see of you can turn in.

In all the years I've spent using rotary tubas, I have never once had trouble with sticking, dragging, or slow rotors the way that piston tubas can get. Then again, I brush my teeth every time before I play (EVERY TIME), so the less crud you blow I'm, the better off everything is.

[PaulMaybery]

I've noticed on new stainless pistons, that the build up is on the casing walls which are brass. (This might also be corrosion rather than lime build up) I can usually feel it with my finger tips. A professional chem clean that will specifically address the casings should help. At first, it may be possible to remove this with a bit of polish on a soft rag, if you can get in far enough with your fingers or a swab. I was actually able to wear down the build up with just my bare fingers, but then it was only a month or so on a new horn and not much more than a soft film.

[PaulMaybery]

Ooops!!! Sorry we were talking about rotary valves. Mea culpa.