Old electrical wiring on my boat has a black coating of oxide (?) on the wires making it impossible to solder. Apart from mechanically removing it, how can I clean them chemically?
Don't laugh but I have heard that Coca-Cola will brighten up tarnished copper coins. I have never tried this but if it's true it should work on copper wire. If it doesn't you can always drink the stuff!
Methinks oldsaltoz is saying replace with tinned. Cleaning old wire can be done with a bit of fine wet and dry but the problem will return. Chemicals? well a splash of nitric acid would remove the oxidation but it is not the route I would take - handling issues, removing it completely afterwards and leaving a nice etched surface to corrode again are three reasons why not.
Believe it or not HP Sauce works a treat ( probably just the acetic acid in it ). Because it is gloopy it stays on the wire overnight then can be rinsed off with a bit of soapy water. Really depends on just how corroded. As a previous post suggested, the only real solution is to replace with tinned wire.
We cut back my old corroded copper wire by almost a foot, looking for something that would take solder. Gave up then and re-wired the whole boat. Being a cheapskate, I used copper again but smeared the joints with silicon rubber and heatshrink...so far so good!
The oxide you are refering to is Cupric Oxide a.k.a. Copper(II) oxide which as it is a basic oxide will dissolve in mineral acids such as hydrochloric acid, sulfuric acid or nitric acid to give the corresponding copper(II) salts:
There is a school of thought that says soldering stranded wire makes it into a solid wire and ,therefore, subject to breaking under vibration as with a solid wire.
If the wire strands are discoloured but otherwise undamaged you can use good quality connectors applied with a ratchet type crimp tool. Connectors with heat shrink tube attached, or adding separate heat shrink tube, will help keep moisture out of the new joint.
It is very, very high resistance. that is why bow lights dont work, but when you test with a meter you can detect the voltage still there.
Best course is to replace the wire with tinned copper wire, and make the joint with the old wire (where the wire is still bright copper) somewhere dry and warm. /forums/images/graemlins/grin.gif
Just to clear up an apparent misunderstanding -
"tinned wire" is referring to wire in which each individual copper strand is individually tinned before the bundle becomes a wire. Therefore it remains flexible and not brittle. Lasts pretty much forever, but costs an arm and a leg even if you can remember to order it before you do the job! Generally unavailable locally.
Fill the crimp with vaseline & then crimp it. add glue lined heatshrink on top. You can now find crimps with the heat shrink & glue as part of the connector. crimp it & then heat to shrink. works a treat.
[/ QUOTE ]Yes, but not as well as Cu.
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Maybe, but I have just rewired my boat because of blackened wire tails which were not conducting at all. And once its there, it comes back very quickly. Like rust on the car.