Unwinding Inductors...

[critofur]

Anybody unwound air core inductors that aren't on a spool? The ones that are "baked" and kind of glued together? Does the insulation come off the wire that you unwind?

I ask because I ordered some 1.5 mH 18 AWG air core inductors for about $5 ea and I figured I could use the wire that I unwind to get them down to the sizes that I'll use (prob. 1.2 mH or .8 mH).

I see the price just went up today on the ones I got (here: http://www.mcmelectronics.com/product/50-725 ) to $5.70. But still, if I needed a .8 mH and something like a Jantzen costs more than $7, I figured I might as well get the cheaper 1.5mH AND get the free wire?

I bought one of the inexpensive LC Meters from Parts Express so I could unwind and/or make my own inductors because sometimes you can't find just the right size in stock.

I wish Parts Express sold something like the cores that Jantzen uses on it's "P-Core" inductors for winding your own.

[stangbat]

I have unwound 7 turns on three of the Jantzen 20 AWG .10 mH inductors for the tweeter filters in the ZDT3.5 LR and Center. I just looked at the wire I removed and nothing seemed to have flaked or come off, the varnish is definitely still intact. And I had to scrape pretty good on the remaining wire so that I could get a good solder connection.

[jkim]

You can unwind a baked inductor to reduce its value. Insulation does come off but mostly from the removed wire, and even if it comes off the remaining wire on the coil, the bare areas don't touch each other. You cannot rewind or reuse the removed wire.

[critofur]

You can unwind a baked inductor to reduce its value. Insulation does come off but mostly from the removed wire, and even if it comes off the remaining wire on the coil, the bare areas don't touch each other. You cannot rewind or reuse the removed wire.

Well, sounds like it depends on which brand then? Some you can, some you can't. Hopefully with the ones I get, I will be able to reuse the wire.

You can certainly reuse the wire from most of the air core inductors that are wound on spools and taped, rather than glued, to hold the wire together.

[stangbat]

For grins, I just took the ohm meter to some of the wire I had removed. Everything was fine until I got towards the end of what I unwound. Maybe the last 6 inches. This wire was unwound and then wound up again, then unwound to test. So this is really not a scientific test, but it does suggest that you'd probably better be careful as jkim stated.

[jkim]

Well, sounds like it depends on which brand then? Some you can, some you can't. Hopefully with the ones I get, I will be able to reuse the wire.

I meant Jantzen Air Core. I've unwound quite a few Jantzen 18 and 20 gauge ones.