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Brass turns to Rust color

April 8, 2009

why does brass turn to a rust color?
Will it eventually turn black and then green

Skip Heal
lighting manufacturer - Exeter, New Hampshire

Hi, Skip. The photo you supplied is rather low resolution, so I'm not sure. Plus, you are the manufacturer, so I don't feel comfortable telling you what material you are using :-)

Still . . . that sure looks like rust to me -- indicating that the material is not brass, but brass plating on steel, which has already failed. Please try to take a high quality close-up, or just test the fixture with a magnet.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 10, 2009

My Dear,You are using your article in outdoor atmosphere.It is nothing but the oxidation of brass.Have you done any lacquer or not?

Gulshan Sachdeva
- Moradabad, Uttar Pradesh, India
April 28, 2009

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Skip, As Ted says, your picture is not very clear and it could be rust or many other things. You do not say if your brass lights are solid brass or just plated. If they are plated, the brass coating has weathered off to expose the base steel. You may not have noticed this, because a small hole in the brass layer will let the elements in and you will get corrosion underneath the brass and this will suddenly lift off the brass layer.
If your lights are solid brass, the brown colour could be general oxidation of the surface, or it could be dezincification. This is usually only found in waters that attack the zinc in the brass and dissolve it out to leave the copper - giving it a brown colour. If you live near the ocean, then salt spray can sometimes do this, because of the high chloride levels; it all; depends on the type of brass you have used.
If it is general oxidation of the surface, it should finally turn greenish but will also have a dull brown luster to it.

My opinion is that the brass lights are plated steel and the brass has been weathered off, but perhaps you can illucidate on what you have used.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
April 30, 2009