Cleaning Copper Wire for Soldering?

[Woznaldo]

I would like to know if anyone has any miracle cleaning solution they use for cleaning common garden copper electrical wire to prepare it for soldering? Basically how I can remove the oxides from old wires?

[Andrew Cooke]

IMO, if it's a bit, then wire wool, emery, etc, if it's a lot the wire is scrap.

[Alastair]

Flux. Buy a pot of flux mate, but as Andrew says, if there is a lot of white dust then best to replace the wire. If you can't get hold of flux on its own the the 5 core solder is quite good, just get the wire hot, add solder with said flux in cores and keep it hot for a few secs, then blow the solder off and repeat until clean and the solder sticks...

[Andrew Cooke]

Doh flux, I forgot the 'obvious'

[Scoff]

if the wire is tarnished, gone black, etc, as copper does then flux won't help, the solder will just pour off of the wire and leave the flux stuck to the tarnished crap. you need bright copper.

[Woznaldo]

if the wire is tarnished, gone black, etc, as copper does then flux won't help, the solder will just pour off of the wire and leave the flux stuck to the tarnished crap. you need bright copper.

That was exactly the problem. The wires were black. I tried cleaning most of the black stuff off with some fine emery cloth (all I had to hand) but, as you said, the solder just wouldn't take and actually looked worse afterwards!

[Andrew Cooke]

you need to cut back until you get to good wire, yours is shot. It's like trying to weld to rust..

[Woznaldo]

you need to cut back until you get to good wire, yours is shot. It's like trying to weld to rust..

I've cut the plug off with 75mm tails and then cut the loom back a further 50mm and it all looks the same black colour. I've just crimped the two ends together (new plug and loom) with an inline crimp and it's all working well, which begs the question..... .....is it worth soldering it now?

[Andrew Cooke]

oxidation can run a long way up a wire, personally I'd cut it all out, but it's up to you. As to whether you have a good joint or not depends on the current you're running through it. Generally crimping gives a more robust joint than soldering as it doesn't leave a hard failure point. Motorsport looms are crimped not soldered, but that's using the right wire and crimps, there is a lot of science in it. My loom is soldered.

[Woznaldo]

It's only for the brake fluid reservoir cap low fluid sensor (nivocode), but i've run into this problem before when trying to solder a new relay plug onto an old engine loom.

[Andrew Cooke]

It's only for the brake fluid reservoir cap low fluid sensor (nivocode), but i've run into this problem before when trying to solder a new relay plug onto an old engine loom.

ahh, well it'll be fine then. It's nothing that'll stop you getting home