best way to clean copper?

My favourite is a fibreglass 'pencil'.

snipped-for-privacy@billburg.com wrote in news: snipped-for-privacy@o13g2000cwo.googlegroups.com:

Tarn-X,available at (US)supermarkets,drug stores,Wal-Mart and lots of other places.Inexpensive.

Wipe on,rinse off,dry.

A vague memory that Coca Cola does the job

David

snipped-for-privacy@billburg.com wrote:

I like a diamond nail file for those.

"NSM" wrote in news:LcBxe.126867$on1.100884@clgrps13:

you probably remove a lot more material with the file than with a chemical(polish) like Brasso or Tarn-X. Tarn-X is even easier to use than Brasso.

That's what I need. Sometimes silver points grow peaks and craters. A diamond file in the hands of the skilled (me) works well.

A diamond file may be ok for what you do, but when I say hi current I'm talking 12 to 16 power modules with 2200 amps coming from each into a common buss line. with a combined current of 26400 to 35200 amps. Start taking material off the contacts and your talking some real fireworks if you don't weld everything together. And at that current levels a few mills of oxidation acts like a power resistor and it gets real hot. I had a 3 inch X 5 inch X 1/2 inch thick contact plate with just a little corrosion get hot enough to burn my hand. (I got first degree burns that time) That was before I started to polish the contacts.

I haven't tried Tarn-X

No argument there. I'm cleaning relay contacts - max 5 amps usually and maybe a lot less. I installed a 400 amp 400 volt busbar system once and I did that with a wrench and a heavy hand. Expensive stuff to have burn up on you.

"NSM" wrote in news:SeHxe.75476$wr.33595@clgrps12:

Well,then you are not just cleaning tarnish,you are reshaping eroded contacts,an entirely DIFFERENT task.

I find it works for all cases.

"NSM" wrote in news:ZgWxe.105193$9A2.4019@edtnps89:

IIRC,the OP wanted to clean off a PCB's tarnish. I'd like to see you use your diamond file on a PCB for tarnish removal.

PS;the title of this thread is "BEST way to -clean- copper".

But the topic drifted to "hi current contacts"

For PCBs I'd use an acid.

Lemon juice works fine.

Ron (UK)

Or vinegar.

They used to make something called "board washer" or something like that. An aerosol spray that cleaned gunk and removed tarnish from entire circuit boards. My old man had a can or two of it way back when he had an electronics repair shop. I seem to remember a similar spay cleaner during my Navy days in avionics corrosion control, though it came in a unmarked green can with just a mil spec number. There are plenty of copper cleaners on the market that might give the desired results with a little care and an acid brush or q-tip. Never Dull might be the best bet. It's cotton balls that are doped with a copper cleaning solvent. Can be gotten at any hardware or marine supply shop. Should be safe for any of the components and they're water free.

Trouble is you can't guarantee they won't leave some form of coating on the copper that isn't good for soldering. After all, they're not made for this job.

I favour mechanical cleaning. Fine wire wool or like I said a fibreglass pencil which is made for the job.

Easy, you follow up the de-tarnishing of the surface copper with a light washing with a decent contact cleaner. Say crc electro wash and a bit of compressed air to blow it off?