Metallurgists ahoi

[steffen]

Can anyone tell me why the braided copper wires in my boat get black, and i mean all over its length which is sometimes well over 15 mtr (mast wiring). I can understand it gettinig green oxydised at the begin and the end due to moisture but all over? and every braid?

Is there a chemical way to remove it as it is impossible to solder or tim those blackened wires.

Happy sailings Steffen

 

[ccscott49]

The wires get like that, apparently due to capilary action, taking moisture down the wires, I've seen it aswell, it's quite amazing! I do believe you can clean the ends, with phosphoric acid, but I'm not sure, it might be another acid, not sure what good it would be if all the wire is corroded/coated though.

 

[vyv_cox]

Oxides of copper are either red or black. Sulphates and nitrates of copper are blue/green. Chlorides of copper are white in their pure state but can pick up other colours, especially blues and greens when not pure. Copper hydroxide is light blue. What you are seeing on your wires is copper oxide, due to water penetration of the cables by capillary action. There is no way to convert it back to copper, and I agree it is impossible to solder.

 

[ccscott49]

Thanks, I'll post this one away in my briefcase, its useful info, thanks again.

 

[Chris_Robb]

Re: Tinned copper wire

Whilst the Americans have been using the correct copper wire grade for marine use for years, UK and continental manufacturers in the most part are still using UN-Tinned copper wire, which of course gives you this nice black finish.

There is really no alternative but to rewire the affected cables.

Note that you will not be able to buy Tinned cable in most UKL chandlers. What they sell is automotive cable which is a cheap short term solution, seeing that most boats (Legend included???) will last 30 years or more.

 

[Guest]

Re: Tinned copper wire

I have rewirred a large part of the boat with tinned copper wire (marine grade). Available from Index marine. They inturn are importing from the States. UK Chandlerys are very dissapointing in this respect. I did ask in one if they had marine cable instead of automotive cable. They didn't know the difference.

 

[coliholic]

I noticed the same problem in my olde Freeman 27, though it appeared to affect the negative wire much more than the positive. Anyone else spotted that too and know why?

Ended up replacing lots of wires with automotive type cable and increased size of cable to compensate for any future problem, though whether that was misguided I don't know. Just happened that it was cheaper to buy two whole rolls (one red the other black) of one size rather than odd lengths of different sizes. Did the job though and of course once it was all done and working perfectly, sold the boat, so someone else got the benfit of my hard work.

 

[steffen]

Tks all, it makes me a lot wiser but still has me replacing the wires.
I will try some remedies (don't know what yet) and if i find something to clean at least the ends in order to solder, i will let it be known to the community.

Happy sailing, Steffen