Cleaning old copper wire

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MartinDreaming
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Cleaning old copper wire

Post by MartinDreaming » Feb 21st, '18, 14:12

I have an old copper wire running up the inside of the mast to the mast-head anchor light. I'm looking to solder the ends at the bottom to an Anderson plug, so I can run the light off the 12V battery in the boat. I'd prefer to use the existing wire, because the alternative is to pull the mast down and pull out the old cable, and draw a new one through. The cost of a new wire is negligible, but the time and stuffing around could be significant (I'm not expert at mast-lowering and raising). However, the existing copper wire has gone black, and the solder will not take (I can't get it tinned). Is there some substance that will clean off the old copper wire? Super-concentrated coca-cola, for example, or something more professional-sounding?
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MoodyBlue
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Re: Cleaning old copper wire

Post by MoodyBlue » Feb 21st, '18, 14:47

Merv
Physically remove with Emery paper is the easiest way to get through to raw copper.
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Davidjohn
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Re: Cleaning old copper wire

Post by Davidjohn » Feb 21st, '18, 15:34

Merv,
Blackened copper wiring is trying to tell you something: If it's black there, imagine what it's like along the rest of the length, including at the top of the mast and the connections to the fittings. The black is corrosion usually caused by water "wicking" along inside the insulation, it also appears to be a poor conductor of electricity.

I have a plumbing background and have no formal background in electricianship but have done quite a few low-voltage re-wire jobs on boats, motorcycles and older cars (usually every time I get another one).
Every bit of "ordinary" copper wiring (often speaker wire) that has been aboard the boats for a while has been damaged by the black plague resulting in power failing to get through to the important end in sufficient quantity and reliability to do its job. I think its something to do with the corroded copper goes brittle and breaks down resulting in less copper, more resistance, hence less power finding its way through to the end where it's needed I don't know the technical terms for all that, but I have always replaced it with marine type tinned copper such as that which can be bought by the 50M rolls at Whatwurths. Being tinned it solders easily.

Any thing else is just going to be a temporary Band-Aid job and you will wish you had of taken the time to drop your mast in the first place and used the existing cable as a pull-through for the proper stuff.

I don't know where you keep your boat but maybe you only need to partially drop the mast and pull the new cable through from a nearby building roof and complete the top of the mast job from there.

Good luck with whatever you choose to do.
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Davidjohn
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madmission
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Re: Cleaning old copper wire

Post by madmission » Feb 21st, '18, 18:05

Sulfuric acid should clean up enough to solder assuming modern led lighting at mast top , low current should not be a problem .... high current better to rewire accordingly .

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Re: Cleaning old copper wire

Post by INMA » Feb 21st, '18, 20:18

Never use acid to clean electrical wires, the acid will undermine the soldered joint.

The blackened wire is stuffed, your wasting your time if you think you can make it reliable structurally or electrically.

There are so many good alternatives out there, they have beeb discussed elsewhere on this forum.
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zebedee
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Re: Cleaning old copper wire

Post by zebedee » Feb 21st, '18, 20:54

The real answer is to use tinned wire which is much less prone to corrosion; once wire has gone like that you're really best off replacing it, with good quality crimp connectors being the only alternative approach - and crimping corroded wire doesn't make for reliable connections.
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az100
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Re: Cleaning old copper wire

Post by az100 » Feb 21st, '18, 21:15

INMA wrote:Never use acid to clean electrical wires, the acid will undermine the soldered joint.

The blackened wire is stuffed, your wasting your time if you think you can make it reliable structurally or electrically.

There are so many good alternatives out there, they have been discussed elsewhere on this forum.
I second that.

Using acid to clean stranded copper wire is *really* bad advice.
Not only will the acid mess up any solder joint, it will also wick up inside the insulation and corrode the wire strands unseen there. You then get a nasty intermittent fault to deal with some time after you thought you 'fixed' the blackend wires.

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Re: Cleaning old copper wire

Post by john » Mar 20th, '18, 15:20

Have a crack at following these instructions........... It might help.............

Step 1: Strip the wires to be cleaned.

Step 2: Get 2 containers, one for each solution. They can be paper cups, plastic, glass, bowls, whatever you can find. I have vials, because I am a professional electronics installer and I use these solutions out in the field.

Step 3: Get 1 tablespoon of raw salt, and put it in one of the containers. Fill up the rest of the container with vinegar, and stir the both together. As a general rule of thumb, put as much salt in the vinegar as will dissolve.

Step 4: Get 1 tablespoon of Sodium Bicarbonate, (baking soda) and add it to the other container. Fill up the rest with water, and stir well. Add more baking soda to make it cloudy. The amount is not important, as long as it is alkaline to cancel the acid of the vinegar solution.

Step 5: Put the stripped end of the wire in the vinegar solution, and stir the solution with the wire. any wire you want cleaned needs to be under the solution. Movement of the wire in the liquid speeds up the process.

Step 6: After 2 minutes or so, the wire will look very shiny and new in the vinegar solution. The acid and salt in the solution is etching away the oxides, exposing the bare metal. Make sure the metal is uniformly shiny. Leave it in longer if it is not perfectly clean throughout.

Step 7: Once the wire is satisfactorily clean, remove the wire from the vinegar, and plunge it into the baking soda solution to neutralize the acid's corrosive properties. If the wire was exposed to the air, without neutralizing the acid first, it would quickly corrode again. The baking soda keeps it clean and shiny. Swish the wire around in the baking soda water for about 10 seconds, and then you are done!! Shiny new wire ready for soldering, and conducting once again!!
JH

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az100
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Re: Cleaning old copper wire

Post by az100 » Mar 20th, '18, 21:02

An interesting and simple solution john, thanks for posting.
Now I have a question or two:
have you personal experience of the long term (I mean years) trouble free working of stranded copper wire treated that way? As you know, the acid will wick up the strands (as does any liquid) so does the neutralising solution also wick up as far as the acid went?
And, can you keep the mixed stuff in small sealed containers, like plastic empty pill bottles, with it not going off over time?
Thanks,
AZ100

john
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Re: Cleaning old copper wire

Post by john » Mar 21st, '18, 21:58

I have not tried this yet.
In the next week I will be giving it a go as I have a similar problem with some wires which had gone black.
Sorry I cant be more helpful at this time.
The instructions sound very doable.
JH

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Re: Cleaning old copper wire

Post by INMA » Mar 22nd, '18, 15:18

In the past when I stripped wiring from masts, I found the black damaged wire extended about 1 meter inside the mast where the salt spray seemed able to travel.

In a marine environment, I have my doubts, just treating the bare ends will provide a long term fix.

If you are trailering the yacht, be prepared for all sorts of fun with the deck terminals and fittings.

I never had that issue with INMA, the tip of the mast was too small for a light or wiring.

I forgot to mention what happens if the live wire shorts to ground via the alloy mast. Lots of white powder.

A similar thing happens when live wiring shorts to ground via the outboard motor. The situation is often made worst when solar panels are energising the short to ground.

Rewiring a yacht's electrics is fine if the yacht spends short times in the water; but rewiring a yacht for longer periods on water is a job for trained tradesmen.
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Gezza
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Re: Cleaning old copper wire

Post by Gezza » Mar 22nd, '18, 21:37

Rewiring the boat is no problem, if you have a bit of understanding what you are doing and you use the proper tinned wire and don’t try to be a cheap skate.
As always, don’t try to safe money by getting cheap stuff, it will cost you more on the long run.
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