Unable to solder braided cable of speaker cable

[r042wal]

I am trying to make an extension cable for one of my speaker cable. The cable is braided and it looks and sniffs like copper but I can't solder it. I'm using 60/40 Kester solder, I have tried flux, and even heat on my soldering pencil to 740 deg. It just wont flow. I am trying to solder on banana plugs. Any suggestions? Thanks

 

[Timcognito]

Try on something else like lamp cord and eliminate solder and flux as problems. I have soldered many things in medical devices not many electronics but it is the same. Clean all parts with alcohol, put flux on each part separately, tin each part separately, reflux, heat larger pieces first and longer and quickly join the smaller one. Don't like copper coated aluminum wire its hard to solder.

 

[JeffS7444]

How thick is the wire? Heavy gauge wire can sometimes wick the heat away quicker than the iron can produce it. In some instances, simply changing from a too-fine tip to a broad, chisel-shaped tip may be all that's needed.

 

[sergeauckland]

I gave up on soldering 'speaker cable for the reasons mentioned above. I use connector blocks for any extensions, as much easier, and never found a problem. Any extra resistance due to the connector blocks is utterly trivial.

S

 

[r042wal]

The female casing for the banana plug is substantial though not large. The braid is very light.

 

[r042wal]

I unbraided a length of shielding and twisted it up into a wire. I could not solder it or get solder to flow. I have a solder pot and am going to try that next

 

[restorer-john]

Is the copper somewhat oxidised? Some speaker (and shielded mic) cable can become impossible to solder to when it is old. The outer sheath chemicals react with the copper IMO.

I have a 100M reel of two core shielded microphone cable which has about 92M left on the roll. I used about 8M when I bought the whole roll years back and it was excellent. It looks perfectly fine, but no mater what you do, (flux, cleaning etc) solder will not wick to the outer braid. Basically, it's a doorstop and only about 10 years old.

 

[sam_adams]

I unbraided a length of shielding and twisted it up into a wire. I could not solder it or get solder to flow. I have a solder pot and am going to try that next

Do you have a pic of said cable so we can see what you're working with?

 

[Soandso]

Prep it by manually causing abrasion to the exposed surface with fine grit sandpaper?

 

[HarmonicTHD]

What @JeffS7444 said. Try the largest solder tip (chisel shape) you have.

 

[Gruesome]

What gauge/diameter is the cable? What's the wattage of the iron?

 

[DonH56]

I wonder if it is actually CCA and the Cu shreds off when attempting to solder?

 

[Philbo King]

On occasion I've run into weird alloys that just won't solder. Perhaps stainless steel wire braid or something similar (good tensile strength at the expense of conductivity). If so it's simplest to replace it.

 

[Gruesome]

I wonder if it is actually CCA and the Cu shreds off when attempting to solder?

Good point. I'm pretty sure the 12 gauge 'copper' speaker cables I bought on Amazon are actually copper clad aluminum; there is a silvery look to the cut ends, and they also feel a bit light. There were others advertised as CCA, but I specifically picked copper cables. Should have probably returned them, but the price was ok either way, and so far I haven't seen the need to solder them.

 

[Gruesome]

On occasion I've run into weird alloys that just won't solder. Perhaps stainless steel wire braid or something similar (good tensile strength at the expense of conductivity). If so it's simplest to replace it.

Stainless can actually be soldered, but you need a special liquid flux (pretty toxic, if I remember correctly), and high temperature. Plus, as you said, stainless is really bad for electrical cables, unless you need low thermal conductivity and can live with the mediocre electrical conductivity.

 

[r042wal]

Is the copper somewhat oxidised? Some speaker (and shielded mic) cable can become impossible to solder to when it is old. The outer sheath chemicals react with the copper IMO.

I have a 100M reel of two core shielded microphone cable which has about 92M left on the roll. I used about 8M when I bought the whole roll years back and it was excellent. It looks perfectly fine, but no mater what you do, (flux, cleaning etc) solder will not wick to the outer braid. Basically, it's a doorstop and only about 10 years old.

I just cut back the insulation so it is fresh and shiny

 

[egellings]

I am trying to make an extension cable for one of my speaker cable. The cable is braided and it looks and sniffs like copper but I can't solder it. I'm using 60/40 Kester solder, I have tried flux, and even heat on my soldering pencil to 740 deg. It just wont flow. I am trying to solder on banana plugs. Any suggestions? Thanks

Did you clean the copper wire so that it is shiny? I use 0000 grade steel wool to be sure the wire is clean, and if it's copper, I have good success with it. If the wire is actually iron with a copper plating, that might present problems if the plating dissolves into the molten solder during soldering and leaves the iron center exposed, which is more difficult to solder.

 

[DVDdoug]

I'm going to agree, it's probably the wire...

I am trying to solder on banana plugs.

I don't have banana plugs on my speakers but I use a LOT of SOLDERLESS banana plugs at work.

I have tried flux, and even heat on my soldering pencil to 740 deg.

What's the wattage? Something like 30W may be too low. 100W should be plenty for something like this. More power and a more massive tip will help to hold and transfer heat and it should work if there's nothing wrong with the wire.

I have a solder pot and am going to try that next

If that doesn't work, it's the wire.

Lately, I've been using water soluble flux (and solder with similar flux core). It seems to work better than rosin flux. But it does have to be cleaned-off or it can cause corrosion and it should be "approved for electronics"