RED ROT

[eeflattuba]

My local tech was doing a valve alignment on my bb flat neo when he noticed 3 small pinholes on the inside of the front outer 2nd valve knuckle. His diagnosis... red rot.This horn was bought new in feb of 2012.It has always been a well maintained by the same tech with an ultrasonic cleaning every year.Not really sure what to do. Feel kinda sick about the whole thing.

[eeflattuba]

If it was me and if I understand the location correctly from your description, I'd clean up those 3 pinholes holes to good metal and carefully float 1 to 3 little spots of soft silver solder to seal them depending on proximity. I'd also have a good look around elsewhere on the tuba afterwards.

That is exactly what he did and then proceeded to inspect the horn for the next 3 hours. My tech is a very close friend of mine and he is VERY PARTICULAR.

[Hsprouse]

Red rot on a 2012 tuba? How common is it to appear that quickly?

[largobone]

Sounds like it's time for a chem clean to stop the red rot from spreading, otherwise it sounds your tech covered about all the bases already. At the very worst, you've got a horn that's infected with red rot, which will be a problem in 10 more or more years. Red rot takes so long to do any actual damage to the horn, I wouldn't worry about it unless you're especially particular to the cosmetics of your nice shiny Neo.

[eeflattuba]

Sounds like it's time for a chem clean to stop the red rot from spreading, otherwise it sounds your tech covered about all the bases already. At the very worst, you've got a horn that's infected with red rot, which will be a problem in 10 more or more years. Red rot takes so long to do any actual damage to the horn, I wouldn't worry about it unless you're especially particular to the cosmetics of your nice shiny Neo.

This horn has been ultrasonically cleaned every year since I bought it by the same tech. The red rot was noticed AFTER its cleaning when my tech was doing a valve alignment.This is a VERY WELL MAINTAINED HORN.The shop where I bought the horn has been notified and they in turn will be in touch with Yamaha.

[Rick Denney]

I had some little red spots appear under the lacquer on the fifth-valve crook of my Yamaha 621, maybe a couple of years after I bought it. I had it chem-cleaned at the time, and have had no recurrence in the subsequent 23 years. I think it was a spot of acid not fully removed under the epoxy lacquer that they use.

Rick "hoping for a similar outcome for you" Denney

[eeflattuba]

Thanks! Hope this the case. I have owned a besson 981 ee flat for well over 25 years and I have not had one single problem.

[iiipopes]

Hmpft. Red rot should not be an issue on such an expensive, recently manufactured horn. I would insist Yammy replace the parts and pay the tech to install them.

If Yammy refuses, have a lawyer write them a letter about "latent defects."

[Rick Denney]

So, here's a question for the techs:

Do all small red spots indicate a perforated pinhole caused by red rot working its way through from the inside of the tube, or can it be a flaw in the outside surface of the brass, under the lacquer?

Rick "who wouldn't want to lawyer up for a minor cosmetic defect on a four-year-old instrument" Denney

[Dan Schultz]

Hmpft. Red rot should not be an issue on such an expensive, recently manufactured horn. I would insist Yammy replace the parts and pay the tech to install them....."

Without actually seeing the instrument.... I'd bet my bottom dollar that the phenomen was actually 'acid bleed' or a few spots that escaped original lacquer because of dirt or other contamination.

If the problem was truly 'red rot'... the part should have been replaced instead of covered with solder. 'Red rot' showing on the outside of a horn is the result of EXTENSIVE damage from within. This condition is when zinc that's alloyed with copper is leached out of the brass leaving pouous and brittle brass behind. There is no quick fix and other spots will follow shortly.

Respond directly to Rick's question...
I see quite a bit of 'red rot' simply because most of repairs are on older brass instruments. It's usually accompanied by heavy 'white-ish' deposits in the inside. In the center of the red spots on the outside, there is often a tiny black spot in the center... which is a pinhole. That pinhole on the outside opens up to a crater on the inside that's much like a 'bulls-eye' break in glass.

[Donn]

Do all small red spots indicate a perforated pinhole caused by red rot working its way through from the inside of the tube, or can it be a flaw in the outside surface of the brass, under the lacquer?

The Bach Mercedes Son-of-O991 tuba seems to be prone to lacquer acne like that, sometimes (judging from photos) to the point where it's pinkish-red almost all over. Clearly not red rot.

But in the present case,

when he noticed 3 small pinholes on the inside of the front outer 2nd valve knuckle.

I guess there's some ambiguity in the term "inside". The observation was reported from a valve alignment after cleaning, which is a situation where maybe you could literally see what's going on inside, though you'd have to look pretty sharp to inspect the valve knuckles. More plausibly, "inside" means the side that isn't facing out, though it is still on the outside of the tubing.

Pinhole literally means to me that there's a small opening, that goes through. I assume the cleanup and silver-solder procedure outlined above must be applied to the crater inside, and in this case it's the real thing, corrosion/dezincification that ate through to the outside.

And ate through in a few short years, despite regular maintenance. Does that mean a defect? Do we expect tuba manufacturers to select brass alloys that resist this effect, or is it a common liability that most of us escape just because of personal chemistry etc.?

[largobone]

Sounds like it's time for a chem clean to stop the red rot from spreading, otherwise it sounds your tech covered about all the bases already. At the very worst, you've got a horn that's infected with red rot, which will be a problem in 10 more or more years. Red rot takes so long to do any actual damage to the horn, I wouldn't worry about it unless you're especially particular to the cosmetics of your nice shiny Neo.

This horn has been ultrasonically cleaned every year since I bought it by the same tech. The red rot was noticed AFTER its cleaning when my tech was doing a valve alignment.This is a VERY WELL MAINTAINED HORN.The shop where I bought the horn has been notified and they in turn will be in touch with Yamaha.

Ultrasonic cleaning and chem cleaning isn't the same thing. One stops the spread of red rot, the other doesn't. If you would like a potentially cheaper alternative to replacing a part (unless of course Yamaha reimburses you for the part and tech time), give it a CHEM clean.

[arpthark]

Pardon me for not knowing - but doesn't ultrasonic cleaning use some sort of (acidic) cleaning fluid in the tank? I assumed it did.