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I was making a slayer exciter recently and I ran out of copper while winding the secondary up, with a goal of 1300 turns.. I ran out of Cu wire, but I do have a lot of aluminium(37 AWG) wire(enamelled) laying around... Can I use that instead? My guess is it should work, although aluminium is a bit less conductive, but I need some help from experts or anyone who has better knowledge about all this stuff I do have a 18 AWG copper coil for the primary ready (4 windings).

P.S I'm powering the exciter with a 40V DC input, using a MJE3055T power transistor/TIP41C.. the circuit is pretty basic..

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The conductivity being only two thirds of that of copper wire of the same cross sectional area shouldn't be a problem, especially given a very low current application like a tesla coil secondary.

Enamelled aluminum wire will thus be just fine electrically, but mechanically it is problematic: It won't wet with normal solder, be it lead free or not, unless you actually have copper clad aluminum wire. There are some fancy solder/flux combinations that strip the oxide layer and bond with aluminum, but they aren't exactly common. Even crimp connections of AL with copper/brass fittings are problematic, as such joints tend to corrode, but they should still be your best bet in this case. Another option is to terminate the AL wire with conductive epoxy.

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  • \$\begingroup\$ Well, I have a good amount of aluminium wire, and I'm just prototyping with a bread board, so I guess it won't be a big problem when it comes to solder, other than that, if it doesn't change the arc length significantly, I'll be better off with aluminium, because the shop at which I could get copper is too far from where I live, and I don't possiblly have that much time! Thanks man! \$\endgroup\$
    – anuragakella
    May 7, 2017 at 9:42
  • \$\begingroup\$ The aluminum being less conductive will drive the Q of the circuit down lowering the voltage gain, but only by a few %... \$\endgroup\$
    – MadHatter
    May 10, 2017 at 2:32
  • \$\begingroup\$ I have had some success wetting aluminum wire with solder using a razor to scrape the wire while submerged in recently fluxxed molten solder. Don't know how well it will last, though. I think it was common Lead Tin rosin-core. Scraping removes the oxide coating, and the molten solder immediately wets the aluminum, preventing it from getting that near-instantaneous new oxide coating. \$\endgroup\$
    – MicroservicesOnDDD
    Aug 5, 2022 at 19:45
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There's not much difference between copper and alli in a secondary. A TC resonator, when loaded by leaders or sparks, has a very low Q. That is, the losses from those are much larger than the losses of the wire, so the slightly higher losses of alli will not affect spark length significantly.

The main problem is connecting to alli, which needs either a not-very-available solder with a vicious flux, or a mechanical connection.

Don't wind half your secondary with copper and then switch to alli, the discontinuity at the join will be a continuing source of trouble.

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  • \$\begingroup\$ Oh cool! , then I'll go ahead with aluminium! Im just using a breadboard, so I guess I won't have soldering problems! Cool man! Thanks for your help! \$\endgroup\$
    – anuragakella
    May 7, 2017 at 9:40

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