Corroded electrical wires - cleaning?

[skyflyer]

When an electrical cable gets a soaking with salt water the water wicks up the wires by capillary action and the copper strands go black.

Cutting back the cable doesnt work, because of the wicking (I had 6ft of spare and it still wasnt any good after chopping all that off!)

Is there any solution that will remove the corrosion and restore to bright copper so a could electrical connection or soldering can be made?

The problem with scraping or sanding the strands is that you cant get to every side of every strand.

Thanks in anticipation

 

[KevinT1]

If you need to solder then an agressive flux such as sold for plumbing / soldering copper fittings - but make sure you clean it off otherwise it continues to etch the copper.

But if you are using crimp or screw terminals the I can't speak highly enough of Contralube 770 - used it on Sunday on the bow lights where seawater had corroded the wire and you could see it cleaning the wire before your eyes.

Kevin

 

[VicS]

I'd think a good non corrosive flux would do the trick after cleaning as much as possible but if the water has wicked up the cable the only sensible solution is to replace it and to use tinned cable anywhere that might be exposed to salt water.

 

[electrosys]

I've used plumber's acid flux in the past, as a 'field-fix' until replacement was possible.
You might also want to try immersing the exposed cable in concentrated Cillit-Bang - it's reputed to clean-off copper and brass a treat ...

 

[Simondjuk]

You probably have what you need in the kitchen.

Put some vinegar in a small vial and mix in salt until it will no longer dissolve.

Take another vial and put some water and bicarbonate of soda or baking powder, same thing, in it. Add more bicarb until it remains cloudy.

Swizz the wire round in the salt and vinegar mix until bright, clean and shiny. May take a minute or two.

Remove and swizz around in the bicarb solution to neutralise the acid.

Solder away.

 

[nigelmercier]

But if you are using crimp or screw terminals the I can't speak highly enough of Contralube 770 - used it on Sunday on the bow lights where seawater had corroded the wire and you could see it cleaning the wire before your eyes...

I'm a big fan of Contralube 770, but I wasn't aware that it would clean corroded wires; I understood it was pH neutral.

I've often thought what would be the best to remove the black coating, which I guess is Copper Chloride CuCl₂ but I may be wrong. Needs to be something which either removes it, or turns it back into Copper, then becomes neutralised.

Any chemists around?

 

[Simondjuk]

Needs to be something which either removes it, or turns it back into Copper, then becomes neutralised.

You know, you're dead right. How about salt and vinegar followed by baking powder and water?

 

[nigelmercier]

You know, you're dead right. How about salt and vinegar followed by baking soda and water?

Why on earth would you add salt? The vinegar may not be neutralised, it needs something that can be calculated to end the reaction.

 

[Simondjuk]

Calculated to end the reaction? He wants to be able to solder a knackered, oxidised wire which ultimately needs replacing, not win the Nobel Prize.

As for the salt, it means you can sprinkle the mixture directly onto your chips when you've finished cleaning the wire.

 

[nigelmercier]

I meant a chemical which would be "used up" in the reaction and remain inert, that's all.

 

[Simondjuk]

Can't help you there I'm afraid, but I can now tell you that adding the salt increases the ionic strength of the vinegar, apparently and according to Google, so with all usual caveats.

 

[VicS]

Can't help you there I'm afraid, but I can now tell you that adding the salt increases the ionic strength of the vinegar, apparently and according to Google, so with all usual caveats.

With salt and vinegar you would effectively have hydrochloric acid but I dont think the dissociation of the acetic acid in the vinegar would be affected so it would like very very dilute hydrochloric acid.
Perhaps I ought to go read what Google finds on the subject.

 

[Simondjuk]

I found two results on the first page of my search mentioning increases in the ionic strength and decided that was as much as I'd ever need to know about the subject.

I can testify that it's a good method for cleaning up a wire in a pinch, and that's good enough for me.

I didn't do a salt and vinegar versus vinegar only comparison as I only had one wire to clean, but will try vinegar alone out of curiosity the next time I need to clean and solder something that's not really worth cleaning and soldering. If it's less effective than the salt/vinegar mix, I shall be able to say, 'We'll add salt! It will increase the ionic strength of the vinegar, don'tcha know.', even if that is actually utter tosh.