Miah wrote:I have a tab bit of this on my valves in my old Olds Tuba
what is the fix? replating only or can i clean the hell out them or anything? I notice that the valve is not as smooth there and I am just a tad concerned that it will just get worse.
Sounds like plain old valve wear and not the feared "red rot". I'm assuming that you see copper areas on your pistons. The copper is an undercoat for the nickel final plating and is used for two purposes. On worn valves, it's used to add material to the pistons so they can be turned down to be perfectly round before the final hard nickel plating is applied. On new pistons, the copper is used as a "strike coat" that alllows the nickel to better adhere to the pistons.
You'll probably notice that your valves are getting leaky. If this really bothers you, you may want to have the valves redone; if not, you can leave them alone--it won't harm the valves.
cc_tuba_guy wrote:I've got some small (maybe 1/2 cm by 3/4 cm) spot on my 2nd valve slide where it looks like they didn't fully lacquer the horn. It's got all sorts of colors in there. Red, black, brown. Should I be concerned about it?
Sounds downright purty. If it's just bare brass, I wouldn't worry about it.
cc_tuba_guy wrote:I've got some small (maybe 1/2 cm by 3/4 cm) spot on my 2nd valve slide where it looks like they didn't fully lacquer the horn. It's got all sorts of colors in there. Red, black, brown. Should I be concerned about it?
If it's just a poor finish on a 2nd valve slide... and the appearance bothers you... you can always strip the lacquer, buff the slide, and squirt a little clear lacquer on it.
Dan Schultz
"The Village Tinker" http://www.thevillagetinker.com" target="_blank
Current 'stable'... Rudolf Meinl 5/4, Marzan (by Willson) euph, King 2341, Alphorn, and other strange stuff.
cc_tuba_guy wrote:So, what exactly does the bad stuff look like?
The usual places it pops up is on leadpipes and on slide crooks. It manifests itself as red spots or bubbles under silver plating.
Since the leaching of zinc happens from the inside out, by the time you see it, it's usually too late to do anything but patch or replace.
Dezincification occurs because the calcium salts present in saliva react with the zinc, forming a soluable salt, leaving the copper behind., which is usually pretty spongy and weak.
I've got a spot of red maybe a half cm around on my bottom bow at the base of a brace. The spot is always on the "up" side of the tubing, so no moisture has really had a chance to pool there, and it doesn't seem soft. Maybe the laquer just didn't stick properly at the site of the solder joint?
Tubatoad wrote:I've got a spot of red maybe a half cm around on my bottom bow at the base of a brace. The spot is always on the "up" side of the tubing, so no moisture has really had a chance to pool there, and it doesn't seem soft. Maybe the laquer just didn't stick properly at the site of the solder joint?
It's probably a little 'acid bleed'. This is where the soldering flux seeped out from under the solder joint after the horn was cleaned and prior to lacquering. It's fairly common and won't hurt anything. If you really want to clean it up, try buffing the spot and applying some clear lacquer or even clear fingernail polish.
Dan Schultz
"The Village Tinker" http://www.thevillagetinker.com" target="_blank
Current 'stable'... Rudolf Meinl 5/4, Marzan (by Willson) euph, King 2341, Alphorn, and other strange stuff.
Dezincification occurs because the calcium salts present in saliva react with the zinc, forming a soluable salt, leaving the copper behind., which is usually pretty spongy and weak.
I think pH is more of a factor than calcium. I've seen plenty of old horns without red rot and with a good coating of calcium-based salts throughout the tubing. The calcium solubility issue is pH dependent, but pH is more of a factor than the calcium in causing red rot. I've seen horns where the owner had a pH imbalance that turned every bit he touched green, and dezincification had left pitting and layering in those areas. Calcium was not a factor.
It's probably a little 'acid bleed'. This is where the soldering flux seeped out from under the solder joint after the horn was cleaned and prior to lacquering. It's fairly common and won't hurt anything. If you really want to clean it up, try buffing the spot and applying some clear lacquer or even clear fingernail polish.[/quote]
