Tiny hole in piston - what to do about it?

[Vito]

Hi,
I was cleaning a Sterling Virtuoso from a friend of mine when I discovered a hole in the third piston.
I have no clue how it got there or how I can fix it. Can it be fixed in the first place or is this piston beyond repair?
Vito

[davewerden]

Well, THAT's odd! I've never seen it before. There may have been a flaw in the brass at that point. The hole is in the caucade (the inner passage), which is just brass. I would think a repair shop could maybe solder over the hole and smooth out the surface afterward.

[John Morgan]

Really strange. Must have some very aggressive bugs in that horn's case!! I wonder if that was someone's attempt to "vent" the valve!!?? But not exactly the right place for the hole. I would think you could plug that with something. What do dentists put in your cavities (kidding I think)? The outside of the valve looks fine.

[John Morgan]

... The hole is in the caucade (the inner passage), which is just brass...

Dave have you invented a word? I want to use it because it sounds really cool, but I see no definition for it in the dictionary. ("caucade")

[davewerden]

I learned the word from Sterling, actually, while I was still a clinician for them! I've checked it since then and I think it's real. But it's in the scientific/industrial category of words that are often not covered by standard dictionaries.

[Vito]

My guess is that someone brushed the piston in a wrong way or didn't use a proper tool. Anyway, I'll plug it for now with a piece of cork.

[davewerden]

Careful on the solution. Cork could deteriorate quickly in this use (under air pressure with valve oil soaking it), and you may end up with pieces inside the valve.

[Vito]

okay, thanks for the heads up Dave.

[John Morgan]

My thoughts exactly. Cork not good. Not only pieces inside the valve, but inside the valve casing as well. Not good. Take it to a music repairman, and Dave's idea about soldering over it is probably a good one. I suppose with the little hole that when the valves are depressed and the air follows the pathway with the hole, some air is getting siphoned off into the twilight zone (inside the valve). I wonder if that hole could even cause a whistling effect? Surely best to get the hole plugged, but not with cork.

[daruby]

Do not use cork. This should be repaired by a technican. It can be repaired with solder and smoothed as Dave said. The issue is that water will get inside the valve and potentially cause more corrosion. The valves are supposed to breath through the holes at the top and bottom of the piston, but these are not high moisture traffic area like the caucades which tend to collect moisture from the curves and turbulence of air flow through them. I clean the caucades on my valves weekly, and can confirm the amount of moisture that collects there. 4th valve in particular.

[SqueakyOnion]

I had a similar issue with a valve on my Willson 2955. I noticed it one day while cleaning. A dot of flux, some heat, and a dot of solder sealed it right up, and hasn't been an issue since. The hole in your valve looks bigger and maybe jagged. Might need to be burnished flat before soldering, or even a tiny brass plug soldered into the hole, possibly. Take this to an experienced technician who can evaluate it in-person and determine the best repair.

[wizan]

Hi,

I already had the same problem some years ago before a concert and had to fix it alone. I used this http://www.pattex.fr/Pattex/produits-pattex/repair.html and it's still in place...
Hope this can help. Regards.

[Vito]

Thanks for the advice everyone,
I mailed a repairman and he said basically the same thing that you said, to solder it, probably with a little brass plug.
I'll post a picture when the repairwork is done.

[davewerden]

I thought you might enjoy this photo from Facebook, showing a person's 11-year-old Prestige valve. (click to expand it)

[iiipopes]

I think, being a brass instrument, the technical word of what metallurgical method to use to as the best repair method is the word "brazing."