wire corrosion problem

[trombone]

I have some speaker wire that tends to corrode. That is, I solder a spade connector to the wire, wrap it in heat shrink, use it, and it's fine for a while. Eventually, though, I'll notice a channel start to go weak or intermittent and sure enough, the wire has corroded and weakened at the spade connector. I fix it, of course, resolder, rewrap, etc. I use pretty good solder, too. Wonder Solder.

The problem is I like this wire a lot and don't feel like springing for new speaker wire, which is a considerable expense with biwired speakers.

Any suggestions for a technique to avoid this problem? I thought the solder would seal it but it doesn't. Maybe the wire rots from the inside, but I've noticed the problem only at the spade joint. I've never seen any other wire I've used do this.

[Conrad Hoffman]

Are you absolutely sure the solder is rosin core, not one of the organics? Fluxes other than rosin need to be cleaned, or corrosion will result. "No clean" solder is usually just a modified minimalist rosin, so it should be ok. In spite of its being an audiophile thing, I'd switch to a tried and true commercial solder like a 63/37 alloy with RMA core from Kester. (maybe somebody respooled some other solder and sold it to you as hi end audiophile stuff) Even with rosin, I'll usually clean spade lugs with alcohol and a tooth brush. I also clean any joint that will be encased in shrink tubing. This isn't one of those clear jacket wires where the wire turns green inside the vinyl is it...

[Cal Weldon]

[i] clear jacket wires where the wire turns green inside [/B]

That brings back memories.

[KP11520]

Hey trombone,

Just a stupid question.... when you strip the wire before soldering it to the spade and maybe twisting it first, do you tin the wire all the way back to the point it is stripped to first?

When I was a teenager, I was the only one in my neighborhood who was really into HiFi and even had my own soldering gun (like that is something to brag about). So I made my own speaker wires and soldered the spades onto the wire. You guessed it, no tinning first (who knew) and yes Conrad and Cal, it was the clear vinyl wire from Lafayette (remember them). I also lived less than a mile from the bay (salt water and humid in the Summer). And yes it turned green anywhere there was no solder AND back into the vinyl jacket a 1/4 inch. I was ahead of my time, going Green before it became fashionable (I also had a little Fiat 850 four cylinder too if the green wire didn't convince you).

Conrad is right, get the 63/37 Kester Solder or equivilant, it is the best all around solder from PCBs to Speaker Cables. I use a lead-free silver solder for cables but I don't think I want to use it for PCBs or soldering any delicate components. I am not sure the silver really offers any additional benefit other than more expense (that's a benefit?).

Good Luck!

Regards//Keith

[poynton]

Hi.

On a similar topic, in the late 70's, I often worked in Egypt. Due to local employment regulations, for every expat employed, we had to employ an Egyptian in a similar capacity.

On one occaision during Ramadan, we left one guy, a BSc from Cairo University, to make up some inspection lights. He had a roll of twin flex, some light fittings and some plugs.

A simple enough task you would think.

On our return from the bar about 2 hours later, we found no lights had been made.

He was sitting in front of a pile of plastic sheath bits and a similar sized pile of cut wire.

When asked the reason, he explained that the wire was 'rusty'.

Apparently. his degree was entirely theoretical and he had never seen bare copper wire only tinned!!!!

We put him straight and went back to the pub.



Andy