Copper compressor line turning to brass?!?

[dipan]

The copper compressor line that I installed after a single stage pump to an aftercooler is slowly, now after several cycles, turning to a goldfish color resembling brass. I installed it with brass flare fittings and you can see the color approximating the brass fittings.

From a web search, it seems copper plus zinc and high temperature can result in brass. Is it possible there is zinc contaminating the copper or they are adding zinc because maybe it's cheaper than copper?

I don't think this will make a difference in the end because I don't plan on taking it apart and if I did, I would replace the line. The same copper used after the aftercooler does not show any similar effects. This side rarely even gets warm (the aftercooler is working very well).

Is this normal? Should I be worried?

 

[gdocktor3]

I wouldn't worry much. I wouldn't even have noticed.

 

[Empty Pockets]

I wouldn't be concerned. But you may have figured out alchemy.... can you turn lead to gold?

 

[pstemari]

Brass is a alloy of copper and zinc, but I suspect what you're seeing is just oxidation. Copper goes through color changes as it heats up.

For example, this is the bottom of a solid copper tea kettle:



The colors change with the distance from the flame.

Sent from my Nexus 6 using Tapatalk

 

[jakemac]

The copper isn't turning to brass, that would require a whole new smelting process.
You're developing a new issue. The copper is heat hardening from the heat generated by the pump. This means that the copper tube will be less shock resistant and will be more likely to break if hit.

In general, it shouldn't be a problem as long as you're not in the habit of knocking it about.

 

[dipan]

Thanks guys, I won't worry about it.

I just thought it odd as the factory line showed some heat-related discoloration, but not to the shiny golden color of brass.

 

[monkeyspanners]

See it happen sometimes on discharge lines on refrigeration compressors, some wire wool etc would soon bring back the copper colour, its just a surface oxide.