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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.

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.

Thanks Peter,
Vinegar followed by bicarb worked a treat.

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

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

Bakers No3 Soldering fluid.

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

mk1 wrote: ↑Fri Jun 21, 2024 7:25 am 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

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

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

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