Green spots on raw brass

Wyvern · Post by **Wyvern** » Thu Dec 07, 2006 6:55 pm

What causes green spots to appear on raw brass tubas?

I have been told that playing the tuba out in the rain will cause them - is that true?

I have an old Hermann Haag (Swiss) raw brass Eb and just wonder what I should do to stop the dreaded green spots appearing.

Thanks.

tubeast · Post by **tubeast** » Thu Dec 07, 2006 7:05 pm

Hey Jonathan,

that green stuff must be some product of oxidization in combination with contact to organic material (such as skin).
On days of hard playing, this will collect on my raw brass mouthpiece as well as form a green ring on my lips.

Back when I used to play this raw brass 3/4 BBb, green stuff would form on my hands where they touched the instrument.
Raw brass will get a greenish patina when left alone for long times.

Brass polish or lacquer will be your best friends at solving this.

djwesp · Post by **djwesp** » Thu Dec 07, 2006 7:26 pm

Isn't this called Verdigris?

Either way, i don't think it bad for the horn. A lot like tarnish on silver from what I've been told.

If it is just an aesthetic thing polish it off, but i'd keep it for character.

Chuck(G) · Post by **Chuck(G)** » Thu Dec 07, 2006 7:48 pm

The green is the result of copper corrosion in the presence of water. The corrosion products can vary, depending upon what's on the tuba and what's in the air. Copper carbonate, for example, is the product of the reaction between copper and carbon dioxide in the presence of water. But other reaction products arising from air pollution or salts in your saliva are possible.

(P.S. Strictly speaking, verdigris is copper acetate, but the word is also used to describe the color, no matter how it's created).

It's pretty easy to use a metal polish to remove the spots.

You can retard the formation of green spots by applying a good paste wax to your tuba.

quinterbourne · Post by **quinterbourne** » Thu Dec 07, 2006 7:49 pm

Do the green spots rub off? I'm not sure exactly what you're talking about, but a greenish substance did develope on my bare brass tuba (which I have since sold). I would suggest you just wash the bare brass every month, just with water and a soft cloth. I always liked the feel of bare brass after wiping it down.

Art Hovey · Post by **Art Hovey** » Thu Dec 07, 2006 11:44 pm

Acid rain or salt water droplets (such as sweat or sea-water) will cause green spots on raw brass. If you ever take your tuba apart you will find that most of the inside is green. It's just corrosion, like rust on iron, but usually does not go as rapidly.

iiipopes · Post by **iiipopes** » Fri Dec 08, 2006 4:20 pm

Case in point: the souzy I play had been stored under the seats in the crawl space of an auditorium for way too many years. Spilled cola-style soda pop, complete with sugar and phosphoric acid, had dripped through the bolt holes in the concrete floor that the seats are anchored to and left drip-splash-shaped green spots all over the horn. They cleaned up easily, with only a moderate rubbing.

Wyvern · Post by **Wyvern** » Fri Dec 08, 2006 4:24 pm

Chuck(G) wrote:You can retard the formation of green spots by applying a good paste wax to your tuba.

Chuck, Can you suggest what sort of paste wax would be best? I like that idea.

Chuck(G) · Post by **Chuck(G)** » Fri Dec 08, 2006 4:50 pm

Neptune wrote:
Chuck(G) wrote:You can retard the formation of green spots by applying a good paste wax to your tuba.
Chuck, Can you suggest what sort of paste wax would be best? I like that idea.

Well, since you're in the UK, I can recommend this patriotic wax:

Developed by the good folks at the British Museum. Very tough stuff. I'd use it only on those spots where you'll be holding the tuba--any wax will impart a slight haze to shiny metals and you want your bell to continue to look glaringly spectacular (or is that specular?).

Wyvern · Post by **Wyvern** » Fri Dec 08, 2006 6:44 pm

That sounds just the job - Thanks Chuck!