Stripping 40 AWG/45 SWG or finer magnet wire/enamelled copper wire?

Try dipping the end in some xylene (or MEK from a model shop if you can`t get xylene) then wiping the coating off quickly with a tissue.

I`m presuming you know all the reasons not to come into contact with xylene.

Ron

Here's what's always worked for me:

Hold the end of the wire in a lighter or match flame until the varnish just flashes off. You may need to move the flame around a little to char the whole length that you want "stripped."

Take a postage stamp sized bit of fine sandpaper, 600 grit or finer, and fold it over once so that the sanding surface faces itself. Draw the wire thru the folded sandpaper, squeezed gently between thumb and forefinger, several times, turning it slightly between times until the wire is cleaned down to clean copper.

It's actually quite quick and easy.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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But the breaking strain of such fine wire is only a few ounces and wouldn't such heating weaken such wire. My bottle of MEK is now nearly full of empty space and no idea where to get anymore.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Most hardware stores carry it by the quart and gallon here in the US, no idea about UK.

My bottle of MEK is now nearly full of empty

A model shop. Slater`s MEK_PAK

Ron

:To then be able to solder to coarser wire. :Assuming coating will not melt off/evaporate at soldering iron temperature :I tend to grip between 2 fingertips and abraid with the finest grade of wet :and dry paper against a fingertip and turning wire around and repeating a :few times. Would abraiding against a block of rubber be better or some other :process altogether ? for minimised chance of localised (so failure point) :weakness due to stretching near the stripping point. Perhaps a small :fine-grade grind stone in a Dremmel with direction of rotation towards the :bulk of wire, turning the wire .

Forget the burning or scraping options, and there is no need to go out trying to find a source of xylene. Use a rapid paint stripper - it works excellently. Leave it for a minute and then wipe off with a tissue.

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excellently.

I tried some ordinary "slow" paint stripper , gloopy stuff. Scooped into one of those 2cc polythene bottles that expensive military connectors come in. Has a flap lid so can seal and reuse. That takes some time to soften. Contained dichloromethane and methanol. What to look for in contents of rapid versions or trade-name?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Just curious, but if you're winding your own coils, why not use the thermal strip variety of magnet wire? Mechanically stripping the fine stuff is a pain.

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Because I have a few hundred (maybe thousands ) miles of laquered fine copper wire.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

42 "single poly" is about 10 miles to the pound. So you have 100 pounds or so? If you're going to use that much, that's a lot of terminating you're going to struggle with. If you just need a bit and you're packratting the rest, you could sell it on ebay and pick up one or two five pound spools of the thermal strip.

Heating certainly anneals the wire, but if you draw the wire GENTLY thru the sandpaper it will be fine. You may need to do this a few times to get the hang of it without breaking the wire, but I've actually never had a problem with it.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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I've always been wary of chemical because of the possibility of not being able to guarantee the complete nulification of corrosive chemical and unknown long term effect on solder and any heating must weaken the wire.

I agree with you, that if one can make sure that the forces used with very fine emery cloth is less than the backforce drag inherent in the winding process then I think that is the most reliable route.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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So what is the best mechanical technique?

For this finest wire I've only used a single-sided action of fine emery against a finger. As an experiment, later today, I will fold some fine emery, stick a piece of paper either side of a clear space on one flap of the emery, to reduce the grabbing effect of double-sided action with no spacers. Tie the 40/45 wire to a spring guage and try double-sided stripping of the wire and see what the axial forces are, to get down to clear copper.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I think I'll stay with abraided stripping.

Making a paper spaced emery stripper gives lot better control.

So results for 40AWG/45SWG wire tested at a breaking force of 4 oz with knot and 5 oz with rubber clamping. Perfectly good double sided stripping at no more than 2 oz of force. Interspercing with a sheet of paper in the jig, so single sided , only 1 oz.

So even double action and repeating a few times, to strip around, then should comfortably remain within the elastic limit. Or putting it another way much the same as the back-torque for tidy winding of that gauge of wire.

The slight abraiding of the copper can only help for tinning/soldering as compared to any remnant chemical or burning residue.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

:> :To then be able to solder to coarser wire. :> :Assuming coating will not melt off/evaporate at soldering iron :temperature :> :I tend to grip between 2 fingertips and abraid with the finest grade of :wet :> :and dry paper against a fingertip and turning wire around and repeating a :> :few times. Would abraiding against a block of rubber be better or some :other :> :process altogether ? for minimised chance of localised (so failure point) :> :weakness due to stretching near the stripping point. Perhaps a small :> :fine-grade grind stone in a Dremmel with direction of rotation towards :the :> :bulk of wire, turning the wire . :>

:>

:> Forget the burning or scraping options, and there is no need to go out :trying to :> find a source of xylene. Use a rapid paint stripper - it works :excellently. :> Leave it for a minute and then wipe off with a tissue. : :I tried some ordinary "slow" paint stripper , gloopy stuff. Scooped into one :of those 2cc polythene bottles that expensive military connectors come in. :Has a flap lid so can seal and reuse. That takes some time to soften. :Contained dichloromethane and methanol. :What to look for in contents of rapid versions or trade-name?

The slow stuff is no good...

Here's an MSDS for a brand I know works

The active ingredient is Methylene Chloride so an alternative with that chemical in a similar proportion will do the job.

Have you actually tried to solder the wire without removing the enamel first?

Ron

Of course, if the wire is actually polyurethane-covered (not enamel), you don't even bother to remove it. It comes off when you tin the ends (prior to the actual soldering). Even if it is enamel-covered, you may still be able to remove it by trying to tin it using a very hot soldering iron (eg Weller #8 bit) - or, at least, after trying to tin the wire (and apparently failing), the enamel may be crumbly. If so, you can usually scrape it off with your finger nails.

--
Ian

And how fares Cu metallurgy at/after 800 degree F ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I've never tried the one-sided approach, but it's worth testing. Just don't forget to char the enamel first, because I think that's the key to making it come off easily.

I suspect that even those who are used to chemical stripping will find this method to be faster and less hassle. There is some risk of fire, but less than lighting a cigarette, and I prefer to keep the nasty stripping chemicals out of my lungs.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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