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Horns.. all brass or any copper?

Posted: Sat Dec 26, 2015 5:07 pm
by columbia1spring
I have an "accepted standard amplified black and brass? horn approx. 32 inches long.
The bell is extremely oxidized, very dark with about 25% of the bell being green.
I tried removing just the green with a metal polish and now the bell is stained green and white.
White from the metal polish that now will not come off. My goal was to remove the green and leave it
worn and oxidized. I feel now an unwanted complete polish may be in order. So my question is, are all these
bells actually brass and not copper? Does brass turn green? Anyway to remove the green and white now without reaching for the brasso? Windex did nothing, Vinegar was useless as well... I like the old patina look and really am against a full polish...

Re: Horns.. all brass or any copper?

Posted: Sat Dec 26, 2015 5:28 pm
by oldphonographsteve
Yes, the bell is most probably brass. Brass does indeed turn green but only if its really, really tarnished. It is rather hard to get rid of green on a brass phonograph horn. You are going to need a good polish and lots of elbow grease.

-Steve

Re: Horns.. all brass or any copper?

Posted: Sat Dec 26, 2015 5:31 pm
by Hit of the Week
All I have seen are brass.....& yes brass turns green!
In my experience, you're going to have to do a complete, shiny polish.......but I sure don't know everything!......maybe we will hear from someone who has had success at this!

Dale

PS: I'm such a slow typer, Steve had his reply posted before mine! :oops:

Re: Horns.. all brass or any copper?

Posted: Sat Dec 26, 2015 5:58 pm
by Curt A
You will need to do a complete polish of the bell... Once that is done, you can "age" it, but it may not look exactly as it does now. Birchwood Casey Super Blue (or Perma Blue) Liquid Gun Blue will turn it back dark, but it would be a good idea to try it on another piece of brass first to see if you like the look. I have used it on many brass and steel pieces that I wanted to age and it works well. Another thing that might age it like you want is Copper Sulphate (a powder mixed with water that will age copper and brass). Or, after polishing it, don't put anything on to protect the shine and after several years it will darken on its own...

Re: Horns.. all brass or any copper?

Posted: Sat Dec 26, 2015 6:00 pm
by De Soto Frank
"Brass" is an alloy made principally of Copper and Zinc. There are many variations, with other elements added to give the alloy special properties.

The addition of Zinc makes the alloy harder and stronger than pure copper, as well as producing various shades of the "gold" color that brass is known for.

https://en.wikipedia.org/wiki/Brass

The harder, tougher nature of brass enables it to be rolled into relatively thin sheets, thinner, lighter, and sontrger than would be possible with copper or bronze.

I would think that straight copper would be too soft / heavy for a horn.


The green is known as "verdigris", and is caused by oxidation of the copper in the brass alloy. It can be toxic, so do not breathe its dust.


Not sure what to recommend for removal of the green crud.

Re: Horns.. all brass or any copper?

Posted: Sat Dec 26, 2015 6:09 pm
by TinfoilPhono
I'm not aware of copper being used for horns in the US, but it was used for some horns in France. Even there they are scarce, heavily outnumbered by brass, but they are undeniably beautiful. The copper horn on my mahogany French 'trademark' is rather thick and quite heavy.

Re: Horns.. all brass or any copper?

Posted: Sat Dec 26, 2015 7:56 pm
by JerryVan
I can tell you from experience in the antique car hobby that you're way beyond the polishing stage and into the sanding stage. Polish will not remove the heavy oxidation. Sand the bell down with 400 grit wet-or-dry paper to remove the heavy oxidation. Then, work up to 600 grit, then 800, then 1200. When you get that far, you're ready for polish. Before you change to the higher grit, be sure you've removed the sanding marks left by the previous grit. Yes, it's a ton of work. There are no miracle potions. When you're done, you may still see pitting left by the heavy oxidation.

Re: Horns.. all brass or any copper?

Posted: Sat Dec 26, 2015 8:38 pm
by columbia1spring
JerryVan wrote:I can tell you from experience in the antique car hobby that you're way beyond the polishing stage and into the sanding stage. Polish will not remove the heavy oxidation. Sand the bell down with 400 grit wet-or-dry paper to remove the heavy oxidation. Then, work up to 600 grit, then 800, then 1200. When you get that far, you're ready for polish. Before you change to the higher grit, be sure you've removed the sanding marks left by the previous grit. Yes, it's a ton of work. There are no miracle potions. When you're done, you may still see pitting left by the heavy oxidation.
If I go the sanding route, will the 1200 grit sanding marks be polished out doing this by hand? I don't have a buffer?
I will first attempt brasso tomorrow.. then see where I am in regards to the next step... sanding

Re: Horns.. all brass or any copper?

Posted: Sun Dec 27, 2015 11:55 am
by drboruff
The French mahogany "trademark" machine with copper horn is stunning. Here is a picture of an Echo-Tone reflex horn in alternating panels of brass and copper which I acquired a few years ago. Mr. Paul's co-authored book Antique Phonographs Accessories & Contraptions refers to the Echo-Tone horn as "One of the least successful, shortest-lived, and most ugly horns every marketed..." :lol: . This is the only brass and copper example I've ever seen, and this horn was originally fitted for a Victor II. It also has the number 1870 stamped on the inside edge of the 6:00 panel, making me believe it was likely a dealer display or factory sales sample.
David

Re: Horns.. all brass or any copper?

Posted: Sun Dec 27, 2015 1:40 pm
by ambrola
I agree with you David on Rene's machine. I think that is the best looking horn I have ever seen. Your horn is stunning also. What is in the middle of it or is it an aloptical illusion?