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From: "Ashlock,William" <William.Ashlock@edwards.boc.com>
To: rsgb_lf_group@blacksheep.org
Subject: LF: RE: RE: litz wire
Date: Wed, 15 May 2002 12:04:55 -0400
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Jim,

Your posting is like a breath of fresh air! (literally - after trying to use
aspirin on the wire and becoming all but overcome with the fumes!). What you
describe below, particularly the "impervious 
to any chemicals", matches my experiences to a 'T'. I'm sure we have the
same Decca Litz wire. 

I'll check out your method tonight and report back tomorrow.

Many thanks!

Bill A 

-----Original Message-----
From: James Moritz [mailto:j.r.moritz@herts.ac.uk]
Sent: Wednesday, May 15, 2002 9:54 AM
To: rsgb_lf_group@blacksheep.org
Subject: LF: RE: litz wire


Dear Bill, LF Group,

I have a considerable amount of Litz wire recovered from a scrap Decca 
loading coil - as has been said, there is more than one type of enamel 
used. The newer type (usually orange, red or pink) is self-fluxing, which 
is easy, but the type I have is a dark brown enamel that seems impervious 
to any chemicals I have tried, including Nitromors and other types of paint 
stripper. The alcohol burner method removes it well, but with 729 strands 
it is not really practical to burn the insulation off all the strands 
without causing a raging inferno! Similarly, the asprin method works to a 
degree, but it only cleans some of the strands with thick litz wire, the 
residue makes it difficult to repeat the process to clean the remaining 
strands, and the smoke generated is horrendous!

The method I have used is to burn the insulation off with a blowtorch - but 
to do this without burning away a lot of the strands some care is needed. 
First, strip about 70 - 100mm of the plastic sheathing, and un-twist the 
end 25mm so that the strands are like a small paint brush. Then, tightly 
wrap this end in a strip of copper foil, such as might be peeled off a PCB. 
Wrap the strands next to the plastic sheathing in another piece of foil, 
and clamp in a metal clamp or vice - this acts as a heatsink to stop the 
sheathing melting. Then heat the foil-wrapped end with a blowtorch, taking 
care to apply the flame only to the foil, not the strands. The foil gets 
red hot, and the enamel burns off with an oily flame. After it has cooled, 
unwrap the foil - it looks like the enamel has just turned black, but the 
residue can be removed fairly easily by dipping it in water and brushing 
gently with a toothbrush, or rubbing the strands together like cleaning a 
paintbrush, to leave clean copper. Then it can be tinned in the normal way.

I can't say it is an easy method, but it does work with otherwise 
indestructible enamel, and after a few practice runs it gave me 
satisfactory results for my loading coil.

Cheers, Jim Moritz
73 de M0BMU


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