[R-390] Soldering Litz wire

[2002tii]

Roy wrote:

>I've heard that heating litz wire with the  solder iron tip against an
>UNCOATED aspirin tablet will remove the enamel on the strands as slick
>as you please.

Todd wrote:

>Over the years I have found that using a small amount of paint remover
>is the safest way to remove the enamel on fine strands of Litz  Wire
>before soldering.
>
>I use a small paint brush and apply a small drop of Kleen Strip to the
>end of the wire to be soldered, let it set about  10-15 minutes, then wipe
>the end clean with a piece of Kleenex wetted with rubbing alcohol. This
>leaves the fine strands of Litz Wire shiny and clean  and ready to solder.

The new high-temperature synthetic enamels are much tougher, and the 
"old ways" of the home constructor don't work so well nowadays (at 
least with new wire).

The way it is done in industry is with a solder pot -- a little 
electrically-heated crucible that keeps a small amount (anywhere from 
2 oz to 1 lb) of solder melted and up to temperature, so you just dip 
the end of the wire in and wait a few seconds.  Once you've used one, 
you'll be hooked -- and not just for Litz wire, for all tinning 
jobs.  For Litz wire, I generally dip for 5-10 seconds depending on 
gauge and stranding, then dip the tinned end in the most active RA 
flux I can find, then back in the solder pot for 3-5 seconds.  For 
uncoated wire, I dip in flux then into the pot for 2-4 seconds, or 
perhaps a bit longer for things like un-tinned 400-strand 12 gauge.

You have to stir in some flux (not necessarily rosin, but that's what 
I usually use), and skim the dross, every now and then.

It is best to use only non lead-bearing solder in pots (and, for that 
matter, on the bench generally), unless you have your ventilation 
thoroughly worked out.  I have used Sn96/Ag4 solder exclusively since 
the early '80s.  Not only does it avoid toxic lead vapor, it is also 
much stronger than Sn60/Pb40 or Sn63/Pb37.  Like Sn63/Pb37, it is eutectic.

Best regards,

Don


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