Using Transformer wiring to make coils, soldering problem

Thread Starter


Joined Apr 23, 2010
I scrape off the enamel but find it impossible to solder, even if I mash the ends with pliars, it's still virtually impossible, is there a trick to this?

It's a pity because I painstakingly unwound an old 220v-110v transformer to get the wire. Sometimes, having the DNA of a Yorkshireman can be a real pain.


Joined Nov 28, 2008
The simplest reason is the material isn't copper. The other reason being the wire is too thick and conducts the heat away quicker than it gets from the soldering iron.

You'll need to identify the coil material. It is possible to solder aluminium with special type of solder.


Joined Apr 17, 2010
Scrape off the enamel,clean it with isopropyl alcohol and tin it properly.I use normally 60/40 rosin core solder and for soldering this kind of stuff I would use a 30 watts iron.


Joined Dec 26, 2010
I suppose that it is possible that you have found some peculiar enamel, but I've never found this to be all that difficult. Except for really fairly thick wires, it can be difficult to scrape the enamel off with a knife without it breaking. Very fine emery paper might work better.

Some so-called "solderable enamel" is designed to burn off with the heat of soldering, but the iron used must be quite hot, with plenty of fluxed solder applied. A "solder pot" is much better, but probably you won't have one of those. In any case, the smoke is seriously bad for the lungs - avoid breathing it in.

A small gas flame, e.g. from a cigarette lighter could be used to make sure that all traces of enamel have gone, even if it's not the special solderable kind, but this method may melt the thinner wires and will tend to oxidise the surface, so don't do it too long.
I assume that you are an adult, but of course you need to be careful not to burn yourself or set things on fire. Take particular care not to do this near flammable material such as liquid flux.

The oxide may be removed with fine emery on thickish wires, but in any case you need to use good flux cored solder, applied to the iron and wire as you heat it. Never carry the solder to the joint with the iron, as the flux mostly boils away within moments of applying the solder, and will not be effective in breaking through any remaining surface film.

It may help to dip the wire end into some liquid flux, if you can get it (resin based, not corrosive stuff like "Baker's Fluid"). Beware that even resin flux can be harmful, and always read the instructions: it typically contains highly flammable solvents.

Edit: Forgot about the IPA wipe, as mentioned above. Meths. will do too, at a pinch, but never anywhere near a naked flame, as both are very flammable. Really my suggestion of using a lighter is last-ditch, to be tried if all else fails. It's bound to oxidise the surface, so may do more harm than good unless you are up against remarkably tenacious enamel.
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Joined Dec 26, 2010
If it is aluminium wire, I would just forget about using it altogether. If you are following designs which require copper, you won't get the same performance.