# why doesn't brass turn green?



## SE18 (Feb 21, 2008)

Copper seems to turn green over time, having some in the garden from plumbing fixtures. The brass I have outside (rails) turns a nice weathering dusky color and doesn't green.

The reason I ask is b/c in a few months I'll be designing some Decauville "steel" ties for my 7/8 line.

I am using brass rails so could solder them to the copper ties. The other option would be to buy a lot of brass which adds expense. A third choice I'm pondering is to use "tin" cans and soldier those. I'd be using a bench press to shape the ties. The problem with tin is that I'm thinking over time it would completely rust away, as the tin coating is thin.

The fourth option is welding, equipment which I don't have. I do have propane torch so perhaps brazing?

You can tell I'm a bit confused but I have a lot of time to think about this.

Any help appreciated.

Dave V


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## jjwtrainman (Mar 11, 2011)

The main reason brass doesn't turn green is because the brass has only small amounts of copper in it (not enough to cause the chemical reaction that turns copper green.) to me, soldering with a blow torch or mini torch makes the most sense. welding is hard, and most anything else is iffy. hope this helps!







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## SE18 (Feb 21, 2008)

thanks; I guess I can always use a chemical coloring agent on the copper. I'll play around


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## Jerry McColgan (Feb 8, 2008)

What is strange is that I have some LGB brass track that is indoors (in my crawl space) where there are spots of green that have developed over the years. I expected the green "problem" to become more severe but it does not appear to have changed much. It is almost as if water had been dropping on the rails at those spots but above the track is the house floor and possibly an HVAC duct.

In a similar vein I have been looking for a chemical agent for removing the tarnish from brass track that would not damage the plastic ties. I have had some success with KaBoom but recent production bottles now say that it is not for brass.

Jerry


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## jake3404 (Dec 3, 2010)

That is a good question. It has to do with the other materials that are mixed with the copper to make brass. JJW is partially right in some brass alloys have a small amount of copper. However, the alloy of brass that track makers use has to contain a high amount of copper to improve the condutivity of the rail. 

I have to harken back to my Metallurgy classes in school, but the reason brass track doesn't usually turn green is because of when the raw materials are mixed together (primarily Copper and Zinc with a few other added materials), the "way" the material oxidizes changes. I have to think that there is some iron that is mixed in with brass rail to give it a more rigid property and that might also be a reason why we dont see a green color.


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## toddalin (Jan 4, 2008)

I treated some of my track to brass cleaner and it turned green where it was not all removed..., so it can happen. Went away after many years.


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## Totalwrecker (Feb 26, 2009)

Awwww thanks for sending me to Wikipedia! 
Brass is Copper and zinc. 
Bronze is copper and tin. 
Brasses rarely contain more than 35% zinc, it makes stuff too brittle. Other alloys added were in the under 5% range; lead (for machining) iron. aluminum, silicon... 

Turquoise is a copper oxide and ranges from green to blue, I suspect your cleaners remove the zinc and let the copper oxidate to color. 

As for your ties I'd go with copper and paint them to suit your tastes. Should last a lifetime. 

John


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## toddalin (Jan 4, 2008)

Track Magic #1 Cleaner

"Caution, do not get in eyes. Contains diluted phosphoric and citric acids."


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