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hald wrote:Reading the thread, I'm glad the issue of silver came up. I had sticky valve issues with a Jupiter 482. I took it to a local shop and the tech mentioned that silver might be the culprit. When I got home I disassembled the valves, got a flashlight and looked inside the valve casings. There was a bit of silverplate on the inner valve casings in the tops and bottoms. I took damp cellulose sponges, rolled them up and put them in the casings to prevent anything from getting where it shouldn't be (the tubing, etc.). I then got out my Dremel Moto-Tool, and using a white felt polishing pad and Wright's Silver Cream, gave it a quick polishing. I gave each valve casing (tops and bottoms only) about 10 seconds each, polishing the inner casing in a circular manner. I didn't try to completely remove the silver. The Dremel has a fairly high rpm so remember that less is usually best and you don't need to use much, if any, pressure. I used q-tips dipped in Silver Cream to clean the guides, and q-tips dampened with water to clean and rinse the guides. After doing each valve casing (top and bottom) I rinsed the sponges, wrung them out, rolled them up and put them back through the casings to make sure everything was spotlessly clean. I used tweezers to grip the sponges as I turned them and gently pulled them through the casings.

If you find that the silverplate is very thick you can leave the silver cream on a while; it slowly dissolves silver. If you use the Dremel use a very light touch. If you aren't familiar with using a Dremel find someone who is; you can do a lot of damage real quick; and be sure it is plugged in to a GFCI outlet (Ground Fault Circuit Interruptor) to prevent electrocuting yourself (these are the electrical outlets with red and black buttons usually found in the bathrooms, laundry rooms, and kitchens of homes). The valves on my brand new tuba have performed perfectly ever since. I hope this might save you and others some time and elbow grease...
-hald

bloke wrote:I directed Matthew to use a small piece of 2000 grit paper on the inside of the #1 casing (to remove the silver) and only stroke in the direction of the casing (up-and-down)...and to clean it out with paper towels soaked in valve oil when he's done.

Only his first and second valves (the ones used the most, OF COURSE) were sticking. WithOUT removing the (uneven) silver plating from the casing interiors, I was able to get #2 to stop sticking completely.

The #1 nylon guide was a bit dished from being turned in about a half-turn too much...so I carefully filed off the top and the bottom. (Dammit, I brought everything that I could possibly need EXCEPT some friggin razor blades!)

I don't think his guide slots were the culprits after all...I found that (right in the areas that were sticking - when specific sideways pressure was applied to the pistons) there were ports on the pistons where the external wall was "pooched out" around the edges. As the pistons are much harder metal than the casings, all the lapping in the world wouldn't have removed those small bulges. I used c. 600-then-1000-then-1500-then-2000 grit paper (as I was literally sitting down on a 10" concrete curb with no "real" tools) and worked down those bulges around the culprit ports. Again, I was able to do a perfect repair on the #2 piston and it no longer sticks. I simply ran out of time with #1 (I arrived at my final travel destination, Fort Worth, after midnight), but it is much better. I think I'm going to send Matthew a new #1 guide to install. Perhaps that (along with removing the silver from the casing...as oxidizing silver DOES tend to be "grabby") will be the final factors in the #1 problem. Again, I would rate the #1 as 75% better (unfortunately, not yet 100%), but the #2 is (I think...??) now working perfectly.

Good luck Matthew, and best wishes...That was really all I could do for you in thirty-five minutes, squatting down on a curb, with no tools (and no reading glasses either).

- bloke