Chemically stripping magnet wire

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KeepItSimpleStupid

Joined Mar 4, 2014
4,914
Wikipedia: https://en.wikipedia.org/wiki/Formvar

suggests

Formvar is most commonly dissolved in ethylene dichloride, chloroform, and dioxane.[7]

MSDS(Dioxane): https://www.fishersci.com/store/msd...endorId=VN00033901&countryCode=US&language=en

MSDS(Chloroform) https://fscimage.fishersci.com/msds/95979.htm

MSDS(ethelene dichloride) https://www.fishersci.com/store/msd...endorId=VN00033897&countryCode=US&language=en

Anyway you look at the chemicals fall into the nasty category. I picked 1,4 dioxane.

I have some fine guage magnet wore I need to strip. I put some dioxane on a Q-tip and it doesn't seem to do much. It MAY have softened it a little bit and I tried scraping with a razor blade with some success.

@jpanhalt Your probably the best resource. Any suggestions? Did I pick the wrong solvent? I think I can get all three solvents.

The glass bottle has the strangest top. The lid which you tighten has a hole in it. There is the usual gasket on the top of the glass bottle, but the other side would be exposed. Then there is a slip fit rubber cap.

PPE: http://amo-csd.lbl.gov/downloads/Chemical Resistance of Gloves.pdf I don't have any butyl rubber gloves yet. I probably should get some Nitrile gloves.
 

jpanhalt

Joined Jan 18, 2008
11,088
1,4-dioxane is similar to diethyl ether. Ether is good for fats, but not polymers like nylon. I doubt it is very good on any of the common, non-solderable magnet wire insulations. I tried chloroform and methylene dichloride on non-solderable magnet wire, and they did nothing. I doubt ethylene dichloride would be effective either. Several years ago, I was interested in doing the same thing and used a molten salt bath containing NaOH or KOH with a little NaNO3. The mixtures are not critical. The insulations tested were all non-solderable. Here is a table of what I found:

1606108838593.png 1606109037221.png

The steel block next to the Table is what I used. The smaller hole(s) were for a thermometer or TC. The big hole was for the molten salt. I just placed the block on a hot plate. If you gave an electric range with coils, it would probably work. I would worry about using a glass top or similar range.

It worked well, and the areas from which the insulation was removed soldered easily, even if they were slightly darkened. More recently, I have read that piranha solution (https://en.wikipedia.org/wiki/Piranha_solution) will work, but have not tried it. That, of course, will also etch copper, so timing with fine wire might be critical.
 

jpanhalt

Joined Jan 18, 2008
11,088
Many different magnet wire insulations are used (https://mwswire.com/insulation-characteristics/ ). If you have a low-temperature, chemically strippable one, then I would use chemicals. Chloroform and dichloromethane (methylene chloride) are two that I keep on hand. Methylene chloride is flammable; whereas, chloroform is not. Dichloroethylene has higher boiling than methylene chloride.

I keep small amounts of a variety of other strong solvents, including dioxane, DMF, HMPA, DMSO, and forth on hand. None worked on the the magnet wire I was using at that time. On other blogs, I have seen recommendations to use brake fluid or brake cleaner. Of course, as is typical for such claims, details are usually lacking. That is, what type of brake cleaner, what type of insulation, and so forth. Nylons are quite resistant to organic solvents, but are susceptible to oxidation. Just like proteins, they can be nitrosated and decomposed. (I am not claiming that is what the NaNO3 does in the mixtures I described earlier. However, notice that some gas was evolved.)

If you are convinced chloroform will work for the insulation on your wire, use it. You can also use a machinist's abrasive stick like Cratex. They are slightly rubbery and will conform to fine wire.
 

Alec_t

Joined Sep 17, 2013
12,149
I usually burn off the insulation on magnet wire by putting the wire briefly in a match flame, then clean the result by sandwiching the wire between two strips of very fine abrasive paper, applying light pressure to the sandwich between finger and thumb, and drawing the wire through.
 

djsfantasi

Joined Apr 11, 2010
7,763
Brake fluid is used in other hobbies for paint removal. I’m familiar with use in modeling or gaming. So far, I haven’t worried about what kind of brake fluid it is. I use generic DOT 3 fluid. It takes an extended period of time to soften the paint. 20-30 minutes. Prestone DOT3 Brake Fluid is available from Amazon with Prime (free shipping) for less than $3. Worth experimenting with.
 
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