cleaning and soldering copper cables

[woodypup59]

I have a bullet which has pulled off a cable (a thin one - for the wipers earth).

Stripping the wire back, the copper has black tarnish and despite attempting clean to bright with abrasive, it won't solder.

Is there a decent acid flux I can use, instead of the 'grease' type flux which doesn't seem to work.

I don't want to use crimps as they look terrible.

[Peter Laidler]

I use one of the basic acids that you'd find in your kitchen. Bleach and oven cleaner spring to mind. I have used acid based wheel cleaner too. Insert bare end into the acid for, say, 15 seconds and it'll come out like a shiny new pin. Ready to solder.

But make sure that you rinse in a clean water and dry before you start to solder.

[woodypup59]

Thanks Peter,
Vinegar followed by bicarb worked a treat.

[snoopy64]

Ketchup overnight if it’s a bit more delicate/thin ..

[Joel Welsh 4769VU]

Barring all of the above-
Ferric chloride will etch, clean, brighten and eat into copper- removing all contamination.

[mk1]

Bakers No3 Soldering fluid.

https://www.amazon.co.uk/Bakers-Solderi ... B00Y3P5JZE

[trevorhp]

Bakers No3 Soldering fluid.

https://www.amazon.co.uk/Bakers-Solderi ... B00Y3P5JZE

Best ever for this job.
And I prefer brown sauce as an alternative

[mk1]

Having tasted Bakers No3 on more than one occasion, I can confirm that Brown sauce certainly tastes better

[Stoneface]

Maybe you already are, but if not, use leaded solder and not the lead free stuff

[minstix]

Definitely old fashioned electrical leaded solder, not the sort used for plumbing. 40% lead 60% tin with flux cores is best.