Any Way To Salvage / Reuse Insulated Motor Wire?

[electromateria]

I have lots of useless motors, is it possible to take out the insulated wire for reuse that in another project? I've noticed that in some motors have epoxy on the coils.. Is there any way to free up the wires without damage?

What are some good sources for salvaging insulated motor wire? Don't want to pay for it but I need huge amounts of it for projects.

[Berni]

You need some pretty aggressive stuff to eat away the epoxy. Whatever eats that would likely also eat the wire enamel, giving you bare copper wire.

People mostly just chisel the copper off and melt it down for scrap copper as a large motor can have quite a valuable amount of copper inside of it.

Technically you shouldn't even reuse the wire after it was been wound on since the enamel might crack. But for DIY things its good enough, the wire is pretty tough.

[Ian.M]

For low voltage DIY projects where a shorted turn in your coil won't cause damage or serious inconvenience, sure you can reuse the wire if you can unwind it in the first place, but the kinks in the wire make it difficult to rewind neatly and there really aren't that many applications for crappy hand-wound coils with possible shorted turns, (so unsuitable for AC or signal use).  That only really leaves electromagnets as a sensible use.

If you have to salvage magnet wire, look at scrap cheap transformers that aren't varnish impregnated, with their windings on a bobbin.  If you remove the core, and make up a mandrel to hold the bobbin so it can turn, you can unwind the wire almost as easily as from a spool.

[Gyro]

Apart from the danger of shorted turns, wire removed from square section formers, motors etc. develope 'sets' where they have gone around corners. This makes it a pain to wind onto other formers. The thicker the wire, the bigger the problem. Attempting to smooth the wire out again adds further risk of damaging the enamel.

[themadhippy]

Dont bother being gentle,get the copper wire out any way you can,take it ,along with the any other metal from the motors to the scrap yard weight it  in and put the cash to buying new  wire

[electromateria]

For low voltage DIY projects where a shorted turn in your coil won't cause damage or serious inconvenience, sure you can reuse the wire if you can unwind it in the first place, but the kinks in the wire make it difficult to rewind neatly and there really aren't that many applications for crappy hand-wound coils with possible shorted turns, (so unsuitable for AC or signal use).  That only really leaves electromagnets as a sensible use.

If you have to salvage magnet wire, look at scrap cheap transformers that aren't varnish impregnated, with their windings on a bobbin.  If you remove the core, and make up a mandrel to hold the bobbin so it can turn, you can unwind the wire almost as easily as from a spool.

Yea I've noticed transformers seem like a good source of low gauge wire. Most of the ones I've checked have no epoxy, also microwave fan coils are another good source for super thin wire. I wish I could find some medium sized motors to salvage from or get rid of that epoxy because I need to find decently long lengths of wire from 12-16 awg. As the wire gets thicker in transformers the length becomes kind of unusable for me.

My project is trying to wind a super low budget but very powerful DC motor. I'm just doing it for learning / experimentation. It seems like if there's a short it will be more of an annoyance rather than something that will destroy expensive components (since there are none).

Apart from the danger of shorted turns, wire removed from square section formers, motors etc. develope 'sets' where they have gone around corners. This makes it a pain to wind onto other formers. The thicker the wire, the bigger the problem. Attempting to smooth the wire out again adds further risk of damaging the enamel.

You guys make some really good points. Thanks for that!

Is there any easy / cheap way to test a stretch of wire for short created by broken insulation?

[SeanB]

Quick check for wire is to have a stainless steel bowl of water, and a little bit of salt in it to make it conductive. then clean the insulation off the one end, connect to your multimeter, and other probe to the bowl. Then run the wire slowly through the bowl, the cracks will show up as a low resistance path to the water. Then you can dry the wire with a cloth, and paint the section with some clear varnish to make it insulated again, easiest with a brush dipped in it, and wiped along the wire, and leave to dry.

[electromateria]

Quick check for wire is to have a stainless steel bowl of water, and a little bit of salt in it to make it conductive. then clean the insulation off the one end, connect to your multimeter, and other probe to the bowl. Then run the wire slowly through the bowl, the cracks will show up as a low resistance path to the water. Then you can dry the wire with a cloth, and paint the section with some clear varnish to make it insulated again, easiest with a brush dipped in it, and wiped along the wire, and leave to dry.

Really great method and tips, thanks!

Attached are some pics of the wire I've salvaged so far.

[Doctorandus_P]

Old fashioned CRT Tv's used to be a quite good source for "enameled" wire, as they have a quite big degaussing coil around the backside of the tube.

[Ian.M]

... if it was actually copper magnet wire.  Back in the mid 80's I remember the disappointment of finding my carefully salvaged magnet wire wasn't solderable, as CRT degaussing coils were one of the early uses of aluminum magnet wire!

[electromateria]

I'm looking to do some testing and need help.

My goal is to figure out a way to remove the epoxy from a coil without affecting the polymer insulation on the wires.

I'm thinking of testing the following:

-Paint thinner
-Coffee bath
-Muriatic acid
-Acetone
-40 year old mystery bottle of yellow acid
-Oven cleaner
-Brake cleaner
-Seafoam
-Gasoline
-Vinegar
-Citric acid
-Alcohol
-Engine oil
-Baking soda bath
-Spray with water, put in freezer see if the epoxy cracks
-Heat gun on low / high
-Methylene Chloride (if I can source it)
-Industrial hand cleaner
-Other random chemicals

If the epoxy and insulation are too similar it will be impossible to achieve, however if there's a product or method that will remove only the epoxy without affecting the insulation I can use my "scrap" motor coils for new projects. I have some new enameled wire, so I can test the affects of the above on that too just to confirm it's not damaging it.

What I need to know is what type of epoxy is used to secure and solidify a coil? Which chemicals or brand of epoxy if possible. 

--

Wikipedia:

Although described as "enameled", enameled wire is not, in fact, coated with a layer of enamel paint or vitreous enamel made of fused glass powder. Modern magnet wire typically uses one to four layers (in the case of quad-film type wire) of polymer film insulation, often of two different compositions, to provide a tough, continuous insulating layer.

Magnet wire insulating films use (in order of increasing temperature range) polyvinyl formal (Formvar), polyurethane, polyamide, polyester, polyester-polyimide, polyamide-polyimide (or amide-imide), and polyimide.[3] Polyimide insulated magnet wire is capable of operation at up to 250 °C (482 °F). The insulation of thicker square or rectangular magnet wire is often augmented by wrapping it with a high-temperature polyimide or fiberglass tape, and completed windings are often vacuum impregnated with an insulating varnish to improve insulation strength and long-term reliability of the winding.

[andy3055]

I think you are trying to do a useless exercise.
I do not believe any of the products that you have listed will do the job. Removing epoxy is something many people have tried but with very poor results. When it comes to magnet wire, the damage to the insulation will be so much that it becomes useless. Spend the money on buying new wire and your projects will be that much more successful.
Just my thoughts.

[Ian.M]

+1

You cannot dissolve cured Epoxy with any solvent as it is a massively entangled highly cross-linked long chain polymer.  Various solvents will soften it to some extent but it will still require significant force to mechanically remove it.    Any chemical  capable of degrading the epoxy by breaking bonds so it can dissolve is (A) likely to be highly corrosive and toxic and generally evil to work with. and (B) will also attack the insulation on the wire.

Also, you have no way of determining the type of insulation on your motor windings, so even if whatever witches brew you try has no effect on your new wire, that doesn't tell you whether or not it will damage the insulation of the wire you are trying to salvage.