r/metalworking • u/dsnisawesome • 5d ago
Questions on copper quality control!
Hello, I just recently joined this sub to see if I can learn some information metals. I have a few questions to ask and would be super grateful to receive answers from anyone!
My questions: Is there a cheaper method to clean the tarnish/oxidization from copper when in bulk? Would there be a way to stop or slow the oxidization of copper, again, in bulk quantities?
Here is the background for my questions: I have been given a task to have massive quantities of copper tubes (2mm diameter, hollow) cut to a certain length and sent to a manufacturing factory. The problem with this is that the copper tubes that were completely fine before the cutting ended up changing colors as it was stored in stock. Now I have a large quantity tarnished/oxidized copper tubes that I cannot use without cleaning the color off. I have talked to a few people around my area who seemed knowledgable and they recommended using an ultrasonic cleaner with DI water (nothing added whatsoever), and this would be the correct method to clean the copper tubes inside-out in bulk.
I know this is a really long and burdensome question, but I had my limits in searching up information - as I am not allowed to test and play around with the copper tubing in stock. I thank you for your time it took to read this post, please get back to me!
Thank you!
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u/ThirdGenRegen 5d ago
You need to pickle them. I don't know much about the process but ultrasonics won't remove tarnish/oxidation
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u/dsnisawesome 5d ago
I'm assuming pickle-ing them means the home treatment for copper cleaning? (Salt & Vinegar soaky soaky) Okay nvm just searched it up. I'll take a look into these! Thank you!
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u/ThirdGenRegen 5d ago
Pickling is a metallurgical process that involves treating the metal in an acid bath to remove the oxide layer. Vinegar might work but typically a stronger acid is used, think hydrochloric acid or similar.
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u/ont_eng 5d ago
Sparex no. 2 pickling compound.
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u/dsnisawesome 5d ago
I'll try this and see if it can be done with minimal costs/time! Thank you for the recommendation!
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u/mckenzie_keith 5d ago
Going forward, to protect them while they are in stock, you may need to coat them with something. A lot depends on the end-use. Could be as simple as a wax, or maybe individually wrap them with a dessicant,pack inside or who knows. In order to solve this, you have to be empowered by management to try a few things. The attitude they have now, "these are in stock, so don't screw with the because they are valuable" that attitude is counter-productive.
Good luck.
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u/dsnisawesome 5d ago
Pretty much nailed the situation I'm in. Stuck between a rock and a hard place. Thank you for the recommendation, I'll look into it!
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u/AccomplishedPop7658 5d ago
Dirty copper? Have you asked the LAPD? They know all about this.
There are two processes that come to mind
Cleaning using phosphoric acid rust remover.
or
Cleaning off the oxidation with electrolysis. With this process you could give them a protective layer of another metal with electroplating by reversing the process. much of this depends on their eventual use.
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u/damnvan13 5d ago
could either pickle or tumble with a dry medium like walnut, same as polishing brass bullet casings.
a silver polishing rag would do in a pinch too.
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u/joesquatchnow 4d ago
Mild vinegar solution heated to less than boiling temps will do it, cheap bulk method
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u/rhino932 5d ago
I don't have an answer for you, but reddit did this...