Red rot or lacquer ruin?

[Lahos12]

Hi ,

My Trombone is a 4 years old, in the past month I started to see some dots on the slide.
Im wondering if thats a red rot or lacquer that ruins?
how i can see the different between them?


Thank you for everyone.

[harrisonreed]

Those both look like lacquer wear from emptying your spit valve.

[Lahos12]

Those both look like lacquer wear from emptying your spit valve.

That's what i thought too but how did water from my spit valve got to this upper area on the slide?
Does it cause damage to the instrument?
What can i do to make sure it wont happen agian?
and to fix it i need to re lacquer that part ?

Thanks agian

[Crazy4Tbone86]

I’m going to disagree on this one. A couple of those spots look like red rot to me. It looks like some of those red spots are blistering in the middle. If they are, it is red rot.

[harrisonreed]

Those both look like lacquer wear from emptying your spit valve.

That's what i thought too but how did water from my spit valve got to this upper area on the slide?
Does it cause damage to the instrument?
What can i do to make sure it wont happen agian?
and to fix it i need to re lacquer that part ?

Thanks agian

No, it's from your hand touching the tubes when you empty your water valve. When you grab the bottom tube to do it, that's where it wears. When you grab the top tube to do it, that's where it wears. You probably do both.

It could be red rot.... But it seems like a pretty coincidental spot for it to just suddenly appear.

You can't fix it without rebuffing and lacquering the entire tube. Don't worry about it.

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[hornbuilder]

That is red rot.

[hornbuilder]

That is red rot.

[BGuttman]

That seems pretty quick to be red rot. Unless you sprayed the slide with acid, it should take well more than a few years to develop.

[greenbean]

Looks like red rot to me, too. But.. so what? Forget about it. If it becomes a problem someday, deal with it then. It will probably be in 25 years and someone else will own the horn.

[OneTon]

Even if it is red rot, it will take 15 to 20 years for it to become a problem. Usually it starts to get crunchy slide syndrome before a through hole develops. If it is a 0.500, 0.508, 0.525, or 0.547 bore slide, the parts should be readily available and it is not prohibitively expensive to accomplish a repair at that point in time.

If it is just a poopy (or thin to enhance maximum resonance response) lacquer job, it does not affect form, fit, or function and never will. Well, the horn will still be around after you’re pushing up daisies.

Loss of lacquer will often present a salmon pink color after a chemical bath. It will turn to a brown color over time. Red rot may tend to remain more of a constant red color. That is not always definitive or easy to discern.

[Lahos12]

Even if it is red rot, it will take 15 to 20 years for it to become a problem. Usually it starts to get crunchy slide syndrome before a through hole develops. If it is a 0.500, 0.508, 0.525, or 0.547 bore slide, the parts are readily available and it is not prohibitively expensive to accomplish a repair at that point in time.

If it is just a poopy lacquer job, it does not affect form, fit, or function and never will (Well, the horn will be around after you’re pushing up daisies.).

Loss of lacquer will often present a salmon pink color after a chemical bath. It will turn to a brown color over time. Red rot may tend to remain more of a constant red color. That is not always definitive or easy to discern.

Hi thank you for the detailed explanation.
This is 500' bore, when you mean that is not expensive to repair, you mean if that's not a red rot? (Just buffing and polish and re-lacquer?) - at repair workshop.

The cosmetic thing annoying me because im cleaning and maintenance the horn in regular basis with all the tips the factories tells.
So i dont understand why a new horn got this dot.

Thanks agian

[MrHCinDE]

I‘ve got a horn with pretty similar looking spots at the crook end of both outer slides. So far I haven’t noticed any crunchiness and have no plans to replace the outers until playability becomes an issue as it‘s a relatively rare beast (Minick small bore) that I‘d like to keep original for as long as possible.

Other than putting away dry, is there anything I can do to slow down (obviously not reverse, that would be nice!) the development of red rot?

[OneTon]

It is not prohibitively expensive to replace those outer tubes, when performance is impacted. The slide will feel choppy after cleaning and lubrication. Technicians run tools through the out tubes to smooth them up, but the slide soon gets crunchy again. The syndrome won’t get started for 15 or 20 years. You need not lay awake at night.

Thin lacquer is thin lacquer. Red rot is most probably due to an excess amount of zinc in the copper zinc alloy to begin with. When the excess zinc decides to depart, it pulls more zinc with it leaving a copper rich area that is more prone to corrosion.

Keeping things clean, wiping down an instrument after use, and shaking down tuning slides like the French horn players helps. In the end entropy increases. You can’t win.

You will have to contact a technician regarding buffing and re-application of lacquer. To perfectly restore finish the plating is re-applied. That could incur a significant cost. There is no guarantee that it won’t happen again.

[BGuttman]

Note that some of the spots (the black ones near the ferrules) are due to flux bleed out from the joints and not red rot. They are tougher to clean, and often grow to a certain size and stay there for years. I have a couple on my Yamaha 682 that appeared in the first month after I bought it and have remained the same size to date (35 years later).

If the "red rot" is due to liquid on the outside, it will polish off. Red rot generally starts from the inside and works out and takes decades to show.

[OneTon]

Renold Schilke claimed silver plated trumpets sounded better than lacquered trumpets. Schilke and Bach put out a lot of silver plated trumpets. Silver plating trombones and tubas gets expensive. It could also be argued that silver plating is thinner and the higher frequencies and perhaps more importantly the higher fundamental frequency of a trumpet are favored by the silver plating. The difference may not be as pronounced or worth it with lower frequency instruments.

The lacquer, if used, is usually kept thin. Thicker and more brittle finishes might preserve a more pleasing cosmetic finish but are probably going to cause the sound to not be as bright or responsive.

[Crazy4Tbone86]

One would think that it would take 20-30 years for red rot to form in brass instruments. In reality, it just needs to be the perfect recipe of a few things, including: brass alloy, thickness of metal, trapped moisture, minerals absorbed in that moisture and a few other things.

When I worked in a retail shop, there were a couple of years in which many of the King rental fleet trombones (King 606) were developing red rot in the brass outer slides in the first one to two years of use. I think it was the early 2000s. Fortunately, that was short-lived and the company switched to better outer slides (possibly a different metal supplier).

I have seen the same “red rot short gestation period” thing with other brass instruments as well. Jupiter trumpets had a red rot problem with leadpipes/main tuning slides for many years. I remember the Holton euphoniums being particularly vulnerable also.