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Trouble soldering telephone wire

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tab a

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No problems soldering components to my board but having a devil of a time getting solder to stick to stripped copper telephone wire I'm using as jumpers. I'm using a 25W Weller iron and 2 decade old Kester "44" resin core solder (60/40).

Thanks.
 
the wire is coated with varnish, it used to be you could burn it off with a lighter, but last time I tried that, it just turned the wire all sorts of funky colors and smoked a lot.

now I use strands of wire from category 5 cable instead ... a little heavier than telephone wire, but no pesky varnish.
 
a little twist with sandpaper, or carefully scraping with a knife at all angles, will remove varnish from a wire for soldering; this is what I do whenever I work with enameled magnet wire.
 
justDIY, the smoke was the varnish cooking =) A quick rub with some scotch bright or sandpaper would have left you with a nice clean wire after you pass it through a flame. Braided wire would be a lot easier it wicks the solder unlike solid core wire and makes a much stronger mechanical bond as well holding up to a lot more abuse. You might want to upgrade your soldering Iron as well 25 watts isn't exactly a lot of heat. I don't know about the solder but I'm not sure if resin ages well, it's not gonna help being 20 years old that's for sure.
 
hardest time I have with telephone wire is getting the insulation off, without damaging the wire

by telephone wire, I'm referring to RJ11 (category 1?) type cable, a bunch of hair like strands, inside color coded insulation (2 pair) with a protective outer sheath - is that what we're talking about here?
 
I use Cat5 too by the way (ethernet). "Telephone wire" is usually Cat 3, though any number of kinds of wire could be used succesfully.
 
Stranded flat telephone wire is used from the phone to its plug. The cover on the wire is silver colour. The tool that installs the plug easily strips off the insulation.

I always use tinned copper vinyl insulated hookup wire.
I use a wire stripper tool, not a wire nicker like electricians use. Wires that are nicked by electricians break when bent. Mine don't break.
 
The telephone wire is old stuff--4 different colors in a sheath.

I had tried scraping the bare copper with a knife and couldn't see a big difference. Will try the flame and Scotchbrite.

I've got a fair assortment of braided wire also, may try that too.

Thanks for the advice!
 
I use the strands from 1.5mm² tps cable which has 7 strands in it.
A bit heavier than telephone wire but very good for making jumpers for circuitboards.
 
hi tab,
On difficult to 'tin' wires I use a plumbers 'flux', paste or liquid.
Just before you touch the 'solder joint' with the iron. dip the solder end into
the paste.
The important thing is to clean the joint very well after cleaning, the 'flux'
is quite aggresive.

You can buy water based fluxes which are more user friendly.

Regards
EricG
 
ericgibbs said:
hi tab,
On difficult to 'tin' wires I use a plumbers 'flux', paste or liquid.
Just before you touch the 'solder joint' with the iron. dip the solder end into
the paste.
The important thing is to clean the joint very well after cleaning, the 'flux'
is quite aggresive.

You should NEVER, EVER use plumbers flux for electrical soldering, it's completely unsuitable - and as you say, highly corrosive!.

If you want to use external flux, then use proper electrical flux, it's freely available as either paste or liquid, with liquid now becoming popular because of the spread of SM parts.
 
hi nigel,

the terms, NEVER, EVER are your personal preferences and opinon.

I have got equipment working in corrosive marine applications, where nothing else will get the soldering job done. Some of these pieces of equipment have been in 24/7 service for years after without the joint re-failing.

I do however totally agree, if the user has access to the correct types of flux he should acquire and use it.

Regards
EricG
 
I don't think his soldering problems were that tough though eric =) And you should be very careful about recommending acidic fluxes to people that don't know exactly what they're doing to begin with. I agree though 'never nver' should never ever be said =) if for no other reason than every method has an appropriate application. Also the 25watt soldering Iron could very well be the main problem, especially with solid core copper wire which wil wick away heat pretty good (they do make heatsinks out of it) A dremel tool with a wire brush or scotch bright and a small butane torch will go a LONG way to clean and prep wire.
 
hi sceadwain.
thanks for the feedback. I agree use with caution!.

Thinking about the times I have had to resort to this type of flux.
I've had to use it mostly on the tags of mains/power transformers, were the manufacturers have used 'solder thru' enamelled copper wires.

Other times are when wires have been 'soldered' to brass/bronze electrical components, or when a component has corroded
away a piece of pcb track and you trying solder in a new component.

The original solder joints have failed due to corrosion due to the harsh on site environments.
As you already know, the pieces of kit that we produce don't always sit on a desk in an air conditioned office.

If the OP has a Weller iron [temp controlled??], I would suggest he removes the solder bit and looks for a 'number' [ single digit] stamped on the blunt end of the bit.
If it has a number, the number relates to operating temp control of the tip. If its a '6' for example it could be to 'cool' for the solder he is using, I use a '7', it gives that little extra heat to quickly heat the joint.

Personally I would never use plain/bare copper wire on a pcb, it tarnishes
and its a pain to tin and solder, also it corrodes in a damp environment especially if its got a few volts on it. [cathodic/anodic corrosion]. It can be varnished to prevent corrosion, but its not worth the hassle.

Regards
Eric
 
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Light some methylated spirit in a metal bottle cap, and heat the wire in the flame until it glows. Plunge the hot wire into the liquid, and withdraw it quickly so it doesn't heat up again. Now tin it.
 
A little flame followed by a little sandpaper and results were much better. Still not as quick and good as the components though, so even though I've got tons of this stuff I'll look for an alternative--and a hotter iron. :)

Thanks for the help.
 
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