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I have the same problem on my 2155 too! What a conincidence~! What exactly is Plasti-Dip and where can you get them?

Aaron

tubaaron wrote:I have the same problem on my 2155 too! What a conincidence~! What exactly is Plasti-Dip and where can you get them? Aaron

Aren't search engines marvelous?

http://www.plastidip.com/consumer/products.html

You can get this stuff at about any industrial supply source such as McMaster-Carr.

I've also heard of tuba players using shrink tubing to do the same thing. Shrink tubing can be had at most electronics supply stores.

I've tried the "plasti-dip" stuff on springs with mixed results. The problem for me was that it didn't stand up to oil very well and soon started to get spongy and flake off. I'd try the heat-shrink trick first.

When a spring is compressed, one of two things HAS to happen: Either the diameter of the spring will get slightly bigger.... or the ends of the spring will scoot on the bottom of the piston or the lower valve cap. It's most likely that the ends of the spring will scoot. This is because as the space for the spring becomes shorter, the length of wire in the spring stays the same. The extra length has to go somewhere. This is the same phenomenon that causes the piston key to 'bang' into the sides of the key slot as the piston rides up and down. I mention the key problem because sometimes this is mistaken for spring noise. In some cases, I have been able to eliminate most or all of the spring noises by:

- Selecting a spring that has just enough pressure to insure that the pistons come back up. Often, heavy springs are used to compensate for what is really poorly fit or damages pistons.
- It's very important the the ends of the springs are square. Set them on a flat surface and see if they stand up straight. Check both ends. If they have been stretched or are distorted in any way... change them. Distorted springs can rub the valve casings.
- I sometimes apply a dab of high-pressure grease like lubriplate or Superlube to the very ends of the springs. Use it sparingly because you don't want the grease to migrate up into the pistons. NEVER oil the valves through the holes in the bottom caps as it will wash crud up into the pistons.
- Keys should be fit as close as possible. This not only insures good piston/port alignment, but also keeps the key from gaining too much speed as it is forced back and forth by the spring action. A very small clearance between the key and the slot will be naturaly filled with piston lubricants and will cushion the banging.

This may, or may not, be related...

Whenever I get a "chick, chick" sound from my pistons (usually after pulling them out to oil 'em), I unscrew the bottom cap a little bit until I feel the spring re-seat itself. Then, I screw it back on. After that, buzzes and chick-chick sounds are minimal, if not unnoticeable.

I'd forgotten about that (it's been a long time since I've played a piston horn) -- used to do that on the YBB321 I played in high school -- it quieted the noises very well!