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Why is so much general purpose connecting wire so hard to solder?
sacentre:
I do a lot of custom cabling for computers and often buy the multi-way ribbon cable of the 18 AWG type - like the stuff supplied with computer PSUs (with the 24-pin ATX connectors etc).
The individual strands appear to be copper under an outer coating of some other metal. This wire is fine for crimped connections but sometimes, I need to solder a connection directly but find solder won't flow easily or quickly. Whatever is used to "tin" the strands, does not appear to be solder of the type used to pre-tin PCBs etc. Someone told me that the tinning is really aluminum and is done for cheapness which would explain it. Can this be the case?
The only cable I see these days that has bare, untinned copper strands (and therefore takes solder readily) is the stuff used for the 2 and 3 core AC mains cable, thin speaker cable and a few others.
Does anyone know if it's possible to buy 18 AWG, multi-strand, solder tinned (if that's what I mean) or bare copper cable?
TIA
Trevor
mariush:
Coating on copper wires should be tin.
Cheap wires are sometimes copper clad aluminum (CCA ) but you can say copper coated aluminum wires.. not the other way around.
On very cheap cables, you often get a mix of steel wire strands and copper clad aluminum wires or copper wires
My guess is that you simply have to use flux and tin the wires yourself. I buy liquid flux, it's quite cheap.. under 10 dollars for a 500ml bottle. A solder pot is also cheap, but you can just use a solder iron tip with a "cup" that holds a bit of solder and you can tin the wires quickly.
Solder pot is often the way to go if you need to tin or solder a lot of wires .. heat solder, wipe away the dross, wet the wires in liquid flux, insert wire in the solder pot and make a figure 8 and pull out and you're done.
ChristofferB:
Nobody 'aluminizes' copper cable. That doesn't make sense. For cheapness, copper cable is sometimes actually copper plated aluminium, and it is not impossible to think one could sand or burn through a thin copper layer to the aluminium.
More likely it's tinned copper. I've become a big fan of using a fluxpen for almost everything, it helps a lot.
You can definitely get tinned, or even silvered cable in all thicknesses you'd ever need, check any major supplier. Personally I like RS.
TMM:
It's probably tinned copper, but the tin is heavily oxidised (due to poor storage/handling during manufacturing) and is therefore causing you more trouble than you expect when soldering. Try using a more aggressive solder/flux (rosin core) and turn up your iron temp (350-400*C).
You'd know if it were aluminium, because it would be virtually impossible to wet with regular electronics solder/flux.
sacentre:
--- Quote from: TMM on November 07, 2021, 02:26:45 pm ---It's probably tinned copper, but the tin is heavily oxidised (due to poor storage/handling during manufacturing) and is therefore causing you more trouble than you expect when soldering. Try using a more aggressive solder/flux (rosin core) and turn up your iron temp (350-400*C).
You'd know if it were aluminium, because it would be virtually impossible to wet with regular electronics solder/flux.
--- End quote ---
Well, that describes what I'm seeing. I thought oxidisation might be the problem so I unrolled a good length off my 10M roll to get a long way from the end but the problem was just as bad even though the strands looked perfectly bright and clean. I have very old but unused PCBs in a drawer that still take solder quickly and cleanly. Next time I'm at the store, I'll try buying a fresh couple meters and see if it's any better.
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