Old copper wiring problem

[careymack]

A lot of my wiring is original plain copper and built into the boat. Where it exits there is often only a short length exposed and this is often heavily oxidised (black on the surface of the copper) Can any bright spark advise me if it is possible to get solder to take? Maybe by tinning it using Bakers fluid?

 

[Spuddy]

I once encountered a long discussion about nature and causes of black wire and got scared off. Soldering however - don't use Bakers cos it's an acid and will eat where you don't want it. Scrape the black off and see if it gets shiny; multicore solder for electronic work will then have a suitable flux in it.

 

[mithril]

I sympathise, I've tried soldering and usually without success. Best result was when I cleaned the strands with wet & dry emery. Its not as difficult as you imagine, give it a go.

BTW if I wanted to blacken copper how would I do it?

 

[kirielad]

Do you mean you are trying to clean the wire before applying solder?

If so you could try Yorkshire Flux (from plumbers merchants), this will clean any oxidation from the copper which prevents the solder from tinning. Its normally used by plumbers when soldering copper plumbing fittings. I would think its safe to use for this as it obviously isn't detrimental to copper in the long term.

You could always smear a little vaseline over the connection afterwards to keep corrosion out.

 

[misterg]

[ QUOTE ]
... Yorkshire Flux (from plumbers merchants), this will clean any oxidation from the copper which prevents the solder from tinning. Its normally used by plumbers when soldering copper plumbing fittings. I would think its safe to use for this as it obviously isn't detrimental to copper in the long term.

[/ QUOTE ]

Plumber's flux is usually very corrosive, and needs to be wiped off copper pipes with a damp cloth after soldering, or else they go green & horrible! I wouldn't think it was at all suitable for electrical connections where it will 'soak' into the strands of the cable, and be impossible to remove - have you used it successfully? I'm happy to be proved wrong!

Cleaning blackened wires back to bare copper by scraping, or rubbing with scotch-brite or wet'n'dry paper is about the only thing that's worked for me when I've been forced to try and solder them.

The real answer is to replace the wire with one with tinned copper conductors (which I'm sure everyone knows, anyway /forums/images/graemlins/frown.gif)

0.02p

Andy

 

[kirielad]

Yes your right some flux types do create an 'orrible green gunge if left, but I haven't noticed this happening with the Yorkshire Flux we used in replacing the pipework on our central heating system after someone recommended it.

Probably not ideal with stranded wire but I thought the original post was asking about solid copper wire?

I would have thought the vaseline would have stopped any 'gunge' appearing anyway - but no doubt someone will be along shortly to put me straight!

 

[VicS]

Do as others suggest and lightly clean the wire. Unless it is very badly corroded a light scaping with a knife will prbably do but also use a flux suitable for electrical and electronic work.

I use Alcho-RE paste flux, made by Fry's Metals. I think it is still available but I don't know where you would get it. I have had my 125g pot for over well 30 yrs and it is still over 3/4 full!

Maplin do a couple of flux dispensing pens. I have not checked RS or Rapid.

Don't use Bakers fluid or killed spirit, as already said it is far too corrosive. Similarly I would not risk the stuff for plumbers.

 

[bobgosling]

Use HP Sauce.

No, seriously. If you don't believe me try it. Dip the end in and leave overnight before washing off with a damp cloth the next day.

 

[mikefleetwood]

Yes, but HP Sauce only works because it is mildly acidic, so the same potential problem of future corrosion as with plumbers flux. Pretty much any chemical that can return black copper to shiny metal does so by acidic action, and will continue to etch the metal away afterwards unless 100% cleaned off!

Safest to remove surface corrosion by scraping/sanding/etc. then use muticore type solder that includes a safe flux. Don't go for the "low residue" or "no-clean" type as the flux is not very active - you want something stronger! "Electronic" solder flux is heat activated and does not continue to etch the metal.

 

[jhughes]

Liberon do a range of chemicals to antique various metals including copper. About £4 for 250ml.

 

[savageseadog]

I'd bite the bullet and get rid of it now and renew. You won't know how much corossion there is further down the cable. Do a proper job and go to sea with a safe seaworthy boat.

 

[mikefleetwood]

I'm inclined to agree. I recently rewired a friend's boat and the blackened copper extended a foot or more along a cable I stripped, just to see what it was like!

 

[Danny Jo]

[ QUOTE ]
the blackened copper extended a foot or more along a cable

[/ QUOTE ] I've seen this too, but is it a problem (assuming you can tin the ends adequately)? Provided the wire is chunky enough (say over 1mm) a bit of surface blackening isn't going to make a lot of difference to its electrical performance.

 

[mikefleetwood]

In this case, it was just a bit of flimsy stuff feeding the loudspeaker - it was best replaced anyway. Also, it had failed in a few places. The rest was just a collection of odds and ends added over the years. I fitted a new fuse/switch panel and all new wiring. It was a working fishing boat, by the way.

It all started when his bilge pump caught a stone and the stalled motor burnt out the wiring - no fuses!

 

[seaesta]

An obvious point but it is well worth sealing up any copper wires before they oxidise. I have done this by pushing the ends into a jar of genuine vaseline. The vaseline itself seems to wick a little and has given protection on my boat in a marine environment for 10 years.
Some folks say that ready tinned wire is much better - but I do not have this installed and am not inclined to replace good wire.
I have seem the oxidation go right down the length of a mast head light wire (10 metres) - so do not assume it is only rotten at the ends!!.

 

[charles_reed]

It makes little difference to

the copper wires' conductivity but one hell of a difference to the connections at each end.

If you check you'll find it's the -ve which always discolours.

I'd suggest the sensible thing to do, to any boat over 15 years old, is to rewire using proper tinned copper marine wire.