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Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 10:44 am
by kirtley2012
I have bought a solid brass phonograph horn, it is good but the problem is that it is very corroded, although it is all brass it was so corroded that the bell was green and the rest was black and felt like a chalkboard, I spent about an hour with some wire wool, I took off a bit of the corrosion, beneath the black corrosion was nice shiny brass but if I keep doing that I will end up with metal lungs, is there a better method?, if not I'll just have to buy some more wire wool and some masks.
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 11:45 am
by fran604g
kirtley2012 wrote:I have bought a solid brass phonograph horn, it is good but the problem is that it is very corroded, although it is all brass it was so corroded that the bell was green and the rest was black and felt like a chalkboard, I spent about an hour with some wire wool, I took off a bit of the corrosion, beneath the black corrosion was nice shiny brass but if I keep doing that I will end up with metal lungs, is there a better method?, if not I'll just have to buy some more wire wool and some masks.
Hi kirtley,
I don't know of a better method, except the use of a powered wheel of some kind, but always use a mask! Those fine particles are hell for your nose, throat and lungs.
I have the same problem with the brass on one of my horns, I spent hours with polishing compound and rags. It helped, but the deep corrosion really needs to be removed more aggressively and I don't have the confidence or knowledge to tackle it, so I live with the few remaining trouble spots.
Best,
Fran
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 12:10 pm
by estott
You might want to try the old citric acid method - a paste of lemon juice and salt. It can cut through some deep corrosion if you let it sit. It will leave brass a reddish color but that can be easily removed. with conventional polish.
The old method was to cut a lemon in half, dip it in salt, then scrub the brass with it - but with the price of lemons as it is a bottle of prepared juice is cheaper.
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 12:45 pm
by kirtley2012
estott wrote:You might want to try the old citric acid method - a paste of lemon juice and salt. It can cut through some deep corrosion if you let it sit. It will leave brass a reddish color but that can be easily removed. with conventional polish.
The old method was to cut a lemon in half, dip it in salt, then scrub the brass with it - but with the price of lemons as it is a bottle of prepared juice is cheaper.
Thanks!, I will try the lemon juice method!, does it damage the brass if left on too long?
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 1:58 pm
by alang
kirtley2012 wrote:estott wrote:You might want to try the old citric acid method - a paste of lemon juice and salt. It can cut through some deep corrosion if you let it sit. It will leave brass a reddish color but that can be easily removed. with conventional polish.
The old method was to cut a lemon in half, dip it in salt, then scrub the brass with it - but with the price of lemons as it is a bottle of prepared juice is cheaper.
Thanks!, I will try the lemon juice method!, does it damage the brass if left on too long?
As estott said, it will leave the brass with a pinkish or redish hue if left on too long. Good old Brasso or similar specialized brass cleaning solutions from the supermarket might also work to get the crud off, or to remove the pink after too much lemon juice.
Andreas
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 2:12 pm
by Henry
I would be very careful about using any abrasive on brass, except perhaps the very finest obtainable, for the reason that leaving minute scratches all over the surface is practically a guarantee of early re-development of the same condition, unless it's lacquered after cleaning. Seems to me, therefore, that the liquid method is far preferable. I speak from experience with brass musical instruments. In fact, if you want the job done right, seek out a competent brass instrument repair person to do the job, but just make sure he or she understands what your objectives are.
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 3:01 pm
by kirtley2012
What are the most important parts of that method, is it the lemon juice or the salt?
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 3:13 pm
by FloridaClay
kirtley2012 wrote:What are the most important parts of that method, is it the lemon juice or the salt?
Alex, as I understand it you need to use both together, but the acid in the equation comes from the lemon. Google "lemon juice and salt to clean brass" and you can find several sites with "how to" instructions.
Clay
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 4:20 pm
by JerryVan
Kirtley,
For very heavy corrosion it's sometimes best to wet sand the brass with very fine sandpaper. Maybe start with 600 grit then work up to 1200. After that, buffing with emery compound then moving up to jewelers rouge will do the trick.
The sanding can help get rid of the etching & pitting left behind by corrosion.
(NOTE: In Europe, sandpaper grits are called out by a different standard than in the U.S.A. You might want to consider that in my U.S.A. based paper grit recommendations.)
Re: Removing corrosion from brass horn
Posted: Tue Jun 03, 2014 7:56 pm
by kirtley2012
I've been using the lemon juice method, it took the thick of it off but there is still quite a bit so come off, the inside of the horn hasn't even been touched yet so i think I will have to resort back to the wire wool (or wet sand) to remove the rest then buff it with the buffing attachment for my dremel.