Message-ID: <134.200006021150@gemini>
From: "James Moritz" <j.r.moritz@herts.ac.uk>
Organization: University of Hertfordshire
To: rsgb_lf_group@blacksheep.org
Date: Fri, 2 Jun 2000 12:57:58 +0000
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Subject: LF: Litz wire stripping method
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Reply-To: rsgb_lf_group@blacksheep.org
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Dear LF Group,
	I recently salvaged some thick litz wire, and have been trying to 
find a workable method of stripping the insulation. The enamel is of 
the older, dark coloured type, which cannot be removed by dipping 
in molten solder. The overall conductor thickness is about 4mm 
with 729 strands, and a spirit burner as previously suggested on 
this reflector just does not make any impression. A blowtorch does, 
but also burns away the outer strands and the plastic sheathing. I 
believe chemical strippers are available, but have to be melted at 
high temperature, and then neutralised afterwards.

However, the following seems to work quite well - strip about 50mm 
of the plastic sheathing, and wrap the end 25mm of wire strands 
tightly in a piece of copper foil (such as can be peeled off some 
PCB laminate, or the type used for EMC shielding). Wrap a smaller 
piece of foil around the 12mm of wire strands nearest the stripped 
back sheathing, and grip with a pair of pliers - this acts as a 
heatsink to protect the sheathing. Heat the foil covered end red hot 
with a blowtorch. The enamel burns off with a small flame at the 
end of the foil, while the foil protects the copper strands from the 
blowtorch flame. When the flame goes out, leave to cool and 
unwrap the foil. The wire strands are coated in black, shiny 
residue, which can be cleaned off by rubbing the end of the wire 
against the bottom of a shallow dish full of water, as if cleaning a 
paint brush. Somewhat suprisingly, this leaves clean, shiny strands 
of copper that can be soldered in the usual way.

Just thought this might be useful to know,
Cheers, Jim Moritz
73 de M0BMU