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Re: bomber rigging

> (Since people always ask me this ) -- where did you get your bombarder, and
> how much was it? I've heard the B&B 10kva units are up to about $500 +
> shipping now...

I bought my 10 kva unit (with a Dayco slide choke) from a neon shop in 
San Antonio that was going out of business.  I paid 900 dollars for both 
- about 6 years ago.

I have my entire bombarder sitting inside a 30 gallon steel drum, with a 
standard 4" metal electric box spot-welded to the outside.  I did this 
mainly so the fire marshal wouldn't get nervous if they pay me a visit. 
Most people seem to get scared when they see a utility transformer 
anywhere but outside up on a pole.

I think the chokemaster is a great idea.  Most people I've seen with 
slide chokes end up just using blocks of wood to hold the thing open at 
various settings.  I think that's bad practice, since you really need to 
change several times during bombing - using an ammeter.I built a 
screw-drive for my slide choke.  I have an "up-down" toggle switch 
mounted on the manifold base.  A 1/4 horse motor turns a threaded rod and 
I can quickly move the choke up and down effortlessly.  It's probably not 
as good as a chokemaster (DC reactance type, right?), but I already had 
the slide, and wanted to make use of it.

I use neon products electrodes too.  And as well, I follow their 
recommended bombing proceedure - closed stopcock.  I flip-flop on whether 
it's necessary to warm the tube and evacuate before beginning the bomb 
proceedure.  It definitly takes more time, but several 'trode 
manufacturers new seem to recommend that.  I usually do it with 
phosphor-coated tubes, usually don't for clear red units.

I've always used a diffusion pump, and it seems unlikely to me than much 
is going to remain in the tube with such extreme vacuum.  I guess the 
object is to have less moisture present _during_ the bomb process, but I 
don't know the merits of this.

One note about bomber flashback:  In my opinion, the best way to prevent
it is to have a grounded electrode between the tube and the rest of the
manifold.  I would think simply grounding a metal manifold would be as
good or better.  I ruined a thermocouple gauge sensor by not having done
so.  Since the grounding electrode - no problems what-so-ever. 

I don't have a "jacobs ladder" on my bomber.  But I've been thinking of
putting one.  I would think it would serve several purposes - reduce
arc-thru potential, reduce electrocution hazard and reduce flashback. You
or someone mentioned a two-inch gap. That seems really big. I would have
thought 1/2 an inch or so, but I've never tried it. 




     -John Anderson