Polish Or Not To Polish??.

[gramophone78]

So George, I take "Victor" for example who wrote many pages on how they went about their craft of building the perfect machines makes no mention of this detail??. I have never notice either. Without question they were polished when new. Now, I have a Berliner all brass that seems to have a period lacquer on it and seems to have been hand applied. So, as you wrote some companys may and others may not have. I wonder if some were just given a wax coating and sent on their way.
I have seen where a person has taken a wonderful brass horn to a power buffing wheel and just made a mess of it. In some areas almost burned thru. Brass that has been spun can become brittle. Therefore extreme caution should be used. In the case of the horn I show. Hand polishing and no more should be fine.

[JohnM]

Paul Baker once told me about a product he uses that is used by professional metal polishers called, IIRC, 'Bright White', or something like that. When brass oxidizes, it forms microscopic pits in the surface that are difficult to polish the oxidation out of the bottoms. 'Bright White' dissolves the oxidation, so that only the brass is contacted by the polishing compound-charged wheel. He also told me about something called 'Lac-Off' (don't laugh) that is an industrial-strength lacquer remover used to strip the metal first. I also understand that if the metal is to be clear-coated by spraying after polishing, it should be done in a warm chamber so that the metal and atmosphere is very dry so that no moisture is trapped between the surface and the clear-coat. This helps prevent the metal from tarnishing quickly. I've never gone through this much rigamarole myself -- I've always used various grades of jeweler's rouge to cut the heavy oxidation and Happich Simichrome polish for a final polish using cotton buffing wheels, and no clear-coat. Polishing can be very dangerous if the wheel manages to grab whatever you are polishing out of your hands. The wheel will sling a small part where you will never find it -- unless it's embedded in your body somewhere. Bad things can happen very quickly. [Bench grinders are much too fast for buffing work -- you should use a dedicated buffing mandrel and a stepped pulley for speed control, and have an assortment of diameters of buffing pads so that you can stack them as needed to make wider surfaces] It's also messy and dusty dirty. Extreme caution, leather gloves (the metal may get quite hot, and your skin would contact the wheel when you are pressing the part into the wheel), a respirator, and a face shield are necessary.

[De Soto Frank]

When I was in college as a Tuba Major ( don't laugh ! ), I became friends with a local gentleman who did instrument repair and refinishing... he learned his craft in new York City, and worked at Giardinelli's Music Store for many years.

In his semi-retirement, he had his repair shop set-up in the basement of his home...

He had a crude "paint booth" and a buffing machine... I spent many hours looking over his shoulder...

I heard / saw several occasions where lacquer-jobs came out cloudy, due to humidity that was too high...

I also heard some war stories about the buffing wheel "grabbing" a part and flinging it across the shop.

His shop was also covered with a reddish=brown film of buffing-dust/lint from the wheels.

If a piece was originally lacquered, it can / will slowly tarnish underneath the laquer... it will also be extremely difficult to hand-polish because you have to scrub-through ( or remove ) that coating before you get to the tarnished metal.

I have a small wheel in my own shop ( 6 " wheel on a ¼ horse motor with a bench-arbor) that I use for cleaning-up nickel parts...

[Henry]

When I was in college as a Tuba Major ( don't laugh ! ), I became friends with a local gentleman who did instrument repair and refinishing... he learned his craft in new York City, and worked at Giardinelli's Music Store for many years....

(OK everybody, this is way O/T, so be warned!)

Hi Frank,
I'm not laughing---trombone major here---crying, maybe, but not laughing As for Robert Giardinelli of sainted memory, I've played on a Giardinelli "Van Haney" model screw-rim mouthpiece for years (on a Conn 88H). I actually bought this in his shop/store on 52nd St. in NYC, right from his hands. I've kept his business card all these many years. I studied with Emory Remington at Eastman, who also taught Lewis Van Haney (second trom. in the NY Phil. for many years).

As for the lacquer stripping thing, I don't know whether it makes a difference, either. It could be a fad, or a "head" thing. Since I retired from playing 13 years ago I don't keep up with trends the way I used to.

Henry

P.S. FYI, Matt Brown, who runs the Online Edison Phonograph Discussion board (http://edisonphonos.proboards.com/index.cgi), is also a tuba player. He's in Reading PA. Where are you located?

[De Soto Frank]

Wilkes-Barre / Scranton area.

[doublemike]

In your opinion, can it worth polishing my brass horn?

[kirtley2012]

it all depends on what you like, do you like it to show its age or not? you will not be doing any damage by polishing it however some people like to keep them "original" and unpolished where as some like them to look almost new

[doublemike]

This phonograph seems "coherent" in this way; but some posts above this I've read "patina is oxidation - - first cousin to rust ", and I've noticed some little green spots. For this reason I'm in doubt if to polish or not to polish (this is the matter ahahahah).

[kirtley2012]

IF you think it may damage it DONT DO IT!, i am no expert on metal corrosion but as far as i know only copper got green corrosion, i think brass just got dull but like i said, i am no expert, there is a chance the green spots are just on the surface and will polish off however like i said above if you are unsure dont do it, better to be safe than sorry

[penman]

To answer your actual question, personally I'd leave it alone, it seems to have a nice patina.

Now to the science part.

Brass is about 70% copper and 30% zinc but there are many different formulas from as little as 5% zinc to more than 35%

Rust: oxides of iron, brass does NOT rust. Rust does not provide a protective layer like:

Copper oxide: The green coating that forms on copper and on brass when the copper component was not properly alloyed, or came in contact with a stronger oxidizer than just the air.

The brown patina is also oxidation but of the alloy, both of these oxides protect the metal underneath from further corrosion, making the metal very stable.