Valve Alignment - No Cork?

[jhedrick]

I seem to be running into a streak of misaligned valves lately and all the same problem - too thick corks.

On my sousaphone, it was so bad I had to totally remove the cork and just go with felt in order to get the ports to line-up (sighting with the 2nd valve tuning slide out.)

All you repair techs out there - is this a problem?

[Dan Schultz]

Must be the shrinking stem phenomonen I've heard about lately.

[Kevin Hendrick]

... shrinking stem phenomonen ...

I hate it when that happens!

[iiipopes]

Just because it says "tuba cork" doesn't mean it fits, and just because it says "euph cork" or something else doesn't mean it should be avoided.

If the wrong corks are on it, get proper thickness corks, and keep after your tech until he/she does so.

And if all else fails, an exacto knife and a wine bottle cork, either natural or synthetic, is not that much of a difficulty, and it can be very enjoyable getting prepped for such an operation, with the right company.

Also, most older instruments have a ring or line machined onto the valve stem that lines up with the top of the valve cap, if everything is stock and in original alignment and working order. Once you get your corks and felts adjusted properly, you might consider scribing alignment lines into your valve stems accordingly.

Yes, felts will swell, then turn brittle and start deteriorating, causing fibers to work into the valve casings. Please consider changing out for the proper felts and corks setup.

[WakinAZ]

The first valve felt on my 1240 would swell so much from trapped water (even with King spins), it would get about 1/8 inch off from 2 and 3. I had to go to a completely non-absorbing material for felts on that valve.

[iiipopes]

So did Renauld Schilke on his trumpets. To this day, Schilke trumpet "corks" are a composite material that doesn't absorb water.

[Lee Stofer]

Virtually all piston-valved brass instruments benefit from the proper felt & cork combination. I have found that the cork (whether natural or synthetic) protects the felt from excessive compression, and the felt washer, even a thin one, will quiet the valve if backed by a cork.

During the last two days at the Conference in Washington, DC, I regulated a number of instruments for customers, and the vast majority of the instruments had the wrong felts and corks (if any). The most popular offending felts were big and red, Allied Supply Corp.'s A-415 sousaphone finger button corks. These are the correct felts (in conjunction with a cork washer) for the Conn 20K and 22K sousaphones, and 2XJ tubas, the ones with offset short-action valves. However, I found these massive felts on everything from F tubas to a Willson CC (!!!) Why? This happened because of ignorance, presumably that of repair technicians. There is a reason why I stock about two dozen sizes and colors of felt washers and at least a dozen different sizes of cork and synthetic cork washers.

If properly maintained, the piston felts will generally stay dry. The presence of valve oil or water may ultimately shorten the life of felts and natural cork, but should cause no short-term problems with alignment or anything else.