Rusty slide

[Euph100]

I have come across small area of rust 😱 on the smallest slide (inside the slide). I don't use it and as it is unused I guess that is probably why it's gone rusty. However it never seems to gather water so it is ignored but maybe I should take more notice of it. How should I clean it away without harming the instrument? Thanks for your help! (besson sovereign compensating 1980's)

[RickF]

Sounds like you're talking about the 1st valve compensating slide (See image below).

Slides are usually made of brass so they don't rust. It could be red rot which means it would have to be replaced.

[tbonesullivan]

Is this visible from the outside of the slide, or is this something you are seeing on the interior of the slide? Are you able to post pictures of this?

You can get corrosion on the inside of slides. It's actually pretty normal. Metal without any protective coating will inevitably become oxidized.

[ChristianeSparkle]

I am curious about it too!

As my slide has a brown spot that looked like rust but a friend who operates an instrument shop said it's nothing to be worried about.

[Euph100]

[ATTACH=CONFIG]7458[5/ATTACH]

Thanks for the feedback, here are two photos, the inside and the outside of the first valve compensating slide. It is the only slide in this condition (after general cleaning).

[Euph100]

[daruby]

Not rust. Just garden variety corrosion. The green stuff on the inside is normal. The brown on the outside of the slide is also normal for a wear spot. Many horns (like Besson, Sterling, etc.) have nickel plating on the tubes of the slide and it wears off over time, exposing raw brass underneath. The brass will oxidize. On old bronze or copper sculptures, they call this "patina" which is considered good. As long as you are not getting red rot (which will go all the way through the metal), this is mostly just surface.

[tbonesullivan]

That's perfectly fine. The green stuff is mineral deposits stained green from the oxidized copper in the brass. You also can get a reddish oxidation on the surface of brass as well. I would just scrub it out a bit, and carry on.

[bbocaner]

Many horns (like Besson, Sterling, etc.) have nickel plating on the tubes of the slide and it wears off over time, exposing raw brass underneath. The brass will oxidize.

No, I'm not aware of any instruments that have nickel plated slide tubes. Nickel plating is sometimes used on the cores of piston and rotary valves, but not on slide tubes.

What you're probably referring to is that many instruments have slide tubes made from solid nickel-silver tubing. Nickel-silver is an alloy of copper, zinc, and nickel which is also sometimes known as German Silver, or "white brass". It's often used for tuning slide tubes because it's harder than yellow brass, so it won't easily deform if you accidentally get a tube jammed in mis-aligned, and also because it resists corrosion better than yellow brass.

It does sometimes get reddish spots of corrosion on it. This isn't that a plating has worn through, it's that copper from within the alloy has migrated to the surface.

[daruby]

Barry, you da man. I stand corrected. However the effect I described is still the same..

[tbonesullivan]

Nickel / German silver is very popular for the outer tuning slide tubes, again because of its more durable nature. Most professional level trombones, tubas, etc have nickel silver outer tuning slides. I think with my Sterling, the entire body is Nickel silver. All of the tuning slide legs are N / S, and unless they plate the inside of the tubes, those are all Nickel Silver as well. Some companies use Nickel Silver for the valve casings, which means when you put in a valve oil like hetman that can lift corrosion away, you end up with orange colored oil when you wipe down the pistons.