Will wrote:

I have some Sony in-ear headphones. The lead to one earpiece has
been cut through completely and I want to rejoin the two wires
(which I will call 'conductors' to avoid confusion).

The two 'conductors' inside the lead are rather thin. And what is
more, each of the two 'conductors' is made up of something like a
dozen smaller copper wires which are woven around some very fine
threads (perhaps the threads are very fine polyester yarn). The
threads run along the lead as the core of the 'conductor'.

The wires of one of these two 'conductors' looks like bare copper
and is unoxidised so I can probably solder to it. But the OTHER
CONDUCTOR is the PROBLEM because its fine wires are enamelled.

How can I remove this enamel coating in order to be able to solder
to the fine copper wires of the 'conductor'?

Below is what I have tried.

Can you advise?

Will

----------------------------

Maybe my general technique is not delicate enough or maybe I am
being too clumsy but this is what I have tried with no success:

(1) Using fine glasspaper but it seems to tear the fine wires
rather than strip their enamel away. Even if the wires don't
break, there is still a portion of uncleaned enamel of the inner
sides of the fine wires.

(2) Using a match to burn off the enamel but this leaves a black
deposit which I have to scrape away with glasspaper and I am back
to the beginning.

(3) Using a gas flame always seems too fierce as it burns through
the wires.

----------------- END -----------------------------

As another poster has suggested, the heat of a soldering tip
may do the job - indeed some fine wire enamels are designed
to convert to a soldering flux on the application of a hot
iron. Dipping the end of the wire in a solder pot for a few
seconds should od the job too.

If you cannot apply heat, then nail varnish remover can work
very well. It may wick up the strands though. Applying a
drop of candle wax first and stripping and trimming back to
the wax should work.

If you don't have nail varnish remover, then I guess paint
stripper may do the job..but nail varnish comes with a handy
applicator brush.

Another thing that can work is a gas blowtorch with a
catalytic converter nozzle that turns it into a tiny hot air
gun. Loads enough temperature to remove insulation (or
heat-shrink tiny sleeves or in a confined space).

--

Sue