Electrode Shape vs Heating

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Original poster: "Marry Krutsch by way of Terry Fritz <twftesla-at-qwest-dot-net>" <u236-at-earthlink-dot-net>

Hi All,

	I was playing with a short jacobs ladder (it was short to allow the arc
to stay at the top until power was cut), and noticed something weird. 
One electrode (both were 10AWG copper) stayed "cool" while the other one
started glowing orange from the tip, down about 1.25".  I switched the
leads, and the same electrode got hot again.  I'm using AC, so the
heating from electron bombardment is the same for both electrodes.

	The only difference between the electrodes is the ROC of the tips.  The
hot one has a larger ROC than the cooler one.  What's the deal???  Has
anyone noticed a difference in heating characteristics between different
sparkgap electrodes of different shapes?

Random question: Where can I get brush replacements for a Powerstat
1256?

Just wondering,
Winston K.

PS-I just exchanged my lemon variac for a better one.  This is the same
model (Powerstat 1256), but is newer than the one I had.  It's only now
that I realize what a piece of crap the old one was.  The old unit got
very warm just sitting there plugged in without a load.  It got even
hotter under a light load.  My new one stays stone cold with no load,
and only rises a few degrees when running at 1/2 of its rated power. 
The solder joints are sensible, and are in good condition.  You guys
wouldn't believe the soldering job on the other one.  This unit's brush
glides almost silently across the windings, while the old one sounded
like an out-of-tune piano.  The new one is in 1000% percent better
shape, and I'm really quite happy with it.  I still got ripped off, but
I don't feel so bad about it now ;-)).