Electronics > Beginners
GROUND wire won't tin... Not a noob question.
CheekyRobot:
Okay, this is driving me crazy. I've been soldering for about 40 years, got plenty of skills and experience all the way down to SMD soldering with a microscope.... so why the question about soldering a stupid wire?
I'm repairing a splice for my external CCTV camera cable. The British weather took its toll.
Pair of double-insulated wires. One a twin pair for 12v power, the other coax for the video.
I cut away about 20cm from each end to avoid any oxidation / moisture etc, stripped the insulation nicely. Red +ve wire tins like a treat, core signal wire on the video cable tins like a treat. Straight away, no problems.
BUT: Can I get the ground on the video or the black ground on the power to tin? No sir. Solder just rolls off both.
Flux you say? Sure, I used flux. Proper leaded flux cored solder, plenty of heat, cleaned the wire, scraped it with a blade, tried mucking about with some offcuts.
Nope, the wire isn't lacquered. Checked a sample with a meter.
The ground wire on the power DOES look slightly darker than the +ve, but I've never had problems with a little oxidation before, bit of flux, abrasion no worries, even with the mankiest bits of wire.
:wtf:
So... what gives?
If I'd had trouble with ALL the 4 wires here then I'd be happy, they ought to oxidise equally...
It's almost like the fudamental CHEMISTRY of the copper has changed... but that's just silly.
james_s:
It's not aluminum is it? With copper prices where they are I've been seeing more and more CCA wire.
I've also on a few occasions had insulation on certain wires react with the copper and make them very difficult to solder. You could try using some find sandpaper or something to clean off the wire.
CheekyRobot:
I did wonder if it was aluminium. I did try sanding it and it looked kind of silvery.
BUT.... would they make one of the pair of wires copper and the other ALU?
How come it's just ONE of the wires in the pair I can't solder?
Doesn't make sense.
ArthurDent:
I've had this problem and it is an oxide. On stranded wire you can try using an xacto knife to scrape each strand so it looks a bright copper color. It is a PITA and if replacing the wire is an option, go for it.
RoGeorge:
If it's Aluminium wire, it can still be soldered under a drop of oil. First, scratch the Al wire until it's shiny, then make the soldering under a big drop of oil. Some are using car engine (unused) oil, but I tried soldering Al foil kept under a big drop of cooking oil, and it worked. The solder nicely wet the Al foil like it was Copper.
If you use the oil trick, either use an old soldering tip, or if you use a good one, cover it in Al foil before diving the heated tip under oil. After soldering under oil, the tip will be very, very hard to clean, will become almost unusable.
The idea with the oil, is that Al will oxidize almost instantly when heated. The drop of oil will keep the Oxygen away from the Al wire.
There is also special "flux" for Al soldering, but I never tested such flux.
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