Re: Searching for Electode Material

Hi Ryan

Copper bolts are a bit hard to find. My boss has a bucketful someone
gave him a while back but all are too large to use for my needs.
Mostly for cap terminals and stuff like that I use the copper studs
out of starter solenoids from GM starters, or the smaller studs out of
Ford starter relays. A couple of either would be good for a gap like
yours. So would copper pipe.
Another thing that would be easy to get would be copper gurneys or
split bolts as they are sometimes called, used to make splices in
larger wires. Another that comes to mind are the acorn clamps used to
bond the ground wire to the ground rod.
Brass bolts should be readily available is sizes up to 5/16 or 3/8,
although around here they are getting hard to find.
Brass is a alloy of copper and zinc. May contain other things too,
some brass has a bit of lead in it. I have used brass (3/4 bar stock)
for a blast gap, but find pure copper more satisfactory. You don't
need to clean it as often as brass, and no chance of getting lead
fumes into the air.
Zinc is not listed in my tables for conductivity or resistivity of
common materials, indicating that it is probably not used for such a
purpose very often. Zinc is reactive electrically however and is used
as plates in batteries etc. It also oxidizes readily and puts zinc
oxide fumes into the air which are poisonous. Not really a good
candidate for a spark gap material. I don't have any info on zincs
thermal conductivity either, but at 100degF, the thermal
conductivities of more popular electrical conductors expressed in
BTU/hr/sqft/deg/foot of thickness are: Aluminum 122, copper 220, steel
25. Copper shines again.
----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, May 05, 2000 8:28 AM
Subject: Searching for Electode Material

> Original Poster: "Ryan Ries" <spud-at-wf-dot-net>
> Hello, I'm looking for some better conductor for my air-blast gap
> what I'm currently using.  I have 1/4" steel bolts for electrodes
> now, and I realize that steel is not good, but I can't find any
copper or
> brass or aluminum bolts.  (Isn't brass just copper with a sodium
> shell?)  Also, does anyone have any info on the conductivity/heat
> dissipation of zinc?
> Thanks,
>        Ryan Ries
>                    http://spud.pureinsanity-dot-net