Re: Aluminum electrodes in TCBOR static gap

To: tesla-at-pupman-dot-com
Subject: Re: Aluminum electrodes in TCBOR static gap
From: Don Allen <dona-at-amigo-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Sat, 16 Oct 1999 07:39:11 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

At 06:44 PM 10/14/1999 -0600, Tesla List wrote:
>Original Poster: Jan Florian Wagner <jwagner-at-cc.hut.fi> 

Hi Jan, All,

>On Wed, 13 Oct 1999, Tesla List wrote:
>> This leads me to believe that aluminum is a very poor conductor at high
>> voltage levels. I'm still puzzled on why it worked well in the first few
>> seconds, but then stopped. I looked at the spray pattern and it doesn't
>> seem to have anything that would stop or impede spark movement. 
>
>I'm far from being an expert on this, but I'd suspect a top layer of Al
>has oxidized to non-conductive (or for HV to high resistance) Al2O3. 
>Happens very easily and very fast even at "lower" temperatures - I know
>this from blasting an aluminium pencil sharpener over a small flame... ;o)

It could be the highly oxidized surface caused by the gap firing that is
causing 
high resistance, I just really don't know.

>Maybe sanding the aluminium parts will make it once again work 30 seconds
>more? Other possibility is that the cap has broken down?

It probably would work if I sanded it, but why do all that work again for just
a 30 sec run? <g> 

The cap works fine. No problems.

Don


http://www.fwpd-dot-net/dona/tesla/teslacoil.htm