[Amps] Stripping Litz

[Manfred Mornhinweg]

Chris,

> Even using the hot air tip on a butane soldering iron for
> a minute fails to do more than darken the insulation, as does a bare
> flame. It's a nightmare to strip,....

Well, MOST Litz wire is of the solder-through variety, but not all of it 
is. You seem to have gotten some extra high temperature Litz wire that 
probably needs some special solvent for stripping, that typically needs 
to be used hot. The manufacturer surely can provide that solvent to 
industrial customers... but a hobbyist most often can't even find out 
who the manufacturer is!

> It's nice
> wire of a reasonable core size for coil winding, but if I can't strip
> it its just X kilos of copper.... :(

Yes. I wouldn't bother with Litz wire that can't be soldered the normal 
way. I suggest you dump it, and get some solderable Litz wire instead.

A note to all those who haven't worked with Litz wire: The strands are 
so fine that stripping them by any mechanical method will rip off most 
of them, or at least weaken them so much that they might fail later. For 
the same reason any chemical strippers that attack copper shouldn't be 
used either.

And yet another note, to Chris and to anyone else trying to tin the end 
of Litz wire or any thin solder-through enameled copper wire:

- Set the soldering iron pretty hot, hotter than for PCB work. If you 
don't have temperature control, you might want to use one of those 
ultra-cheap non-regulated irons of 40 watts or so. They tend to get much 
too hot for normal work, but are great for tinning such wires!

- Tin the tip of the iron, forming a small blob of solder.

- Stick the very end of the wire into this blob. Now start slowly adding 
rosin-cored solder to the blob, so as to maintain a supply of fresh, 
active flux. If the blob gets too large, let it fall off, and keep 
slowly adding fresh solder. The fresh, active rosin is essential in this 
process. With most solder-through insulations a flux-free blob of solder 
won't do, nor will a solder pot.

- When the wire is starting to take the solder, you can slowly push it 
through the blob, while adding solder, to tin as much of its length as 
you need.

With the proper wire, this process is easy, once you learn how to do it 
right. With non-solderable wire, it won't work. Avoid non-solderable 
thin enameled wire.

Manfred

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