Re: Primary Materials (fwd)

---------- Forwarded message ----------
Date: Tue, 21 Jul 1998 00:09:52 -0700 (PDT)
From: Michael Nolley <mhnolley-at-willamette.edu>
To: Tesla List <tesla-at-pupman-dot-com>
Cc: tesla-at-pupman-dot-com
Subject: Re: Primary Materials (fwd)

On Mon, 20 Jul 1998, Tesla List wrote:

> ---------- Forwarded message ----------
> Date: Mon, 20 Jul 1998 06:52:12 -0500
> From: Bert Hickman <bert.hickman-at-aquila-dot-com>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Primary Materials (fwd)
> Tesla List wrote:
> > 
> > ---------- Forwarded message ----------
> > Date: Sun, 19 Jul 1998 00:42:11 -0500
> > From: Adam Parker <park_e_r-at-hiwaay-dot-net>
> > To: Tesla List <tesla-at-pupman-dot-com>
> > Subject: Primary Materials
> > 
> > Once again a fledgling coiler has yet another question. Yesterday I made my
> > flat pancake coil form out of four pieces of 1/2 inch PVC mounted radially
> > on some painted plywood. After making my coilform, I tried winding the
> > thing with thin-wall 1/4 copper tubing. I had trouble. The tubing kept
> > kinking and never formed a good circle. After struggling with about 6 turns
> > I called it quits and removed the tubing. Yesterday's fiasco has swayed me
> > to winding the primary with coax. Now, will using coax reduce coil
> > performance? I thought maybe eventually I could try tubing again and
> > replace it if it does. Do you use both coax conducters or just the outer
> > sheilding? One the coil masters out there should write an article on
> > primary winding (RQ seems pretty with that type of thing) Well, anyway, my
> > next post will either be me asking for help with trouble shooting my
> > completed coil or a link to some great operating pictures. I'm hoping for
> > the later. Thanks Again,
> > 
> > Adam
> Adam,
> You might want to use four more PVC radials so that you have a total of
> eight to provide the copper tubing with a bit more "guidance". Also, by
> spacing each radial slightly more outward as you go around, you can get
> the nice spiral pattern you need. By carefully bending the tubing in or
> outwards from the coiled supply, and then securing it as you go. BTW how
> are you "holding" it in place onto your radials? Winding the primary
> make take an extra pair of hands, one to hold the winding in place while
> the other secures it to the PVC radials. It doesn't have to be
> perfect... it just needs to have adequate clearance between turns so
> that you don't get any turn-turn arcs.  
> Unless you use something like "hardline", most coax uses braid as the
> shield. Braid has been found to be extremely lossy when used to conduct
> the high RF currents seen in a Tesla Coil primary circuit - and will
> introduce an unnecessarily high amount of loss in your system. Even 4 or
> 6 guage THHN copper wire from your local hardware store will work much
> better (and will be less expensive) than coax... 
> Good luck!
> -- Bert --
I think he may be referring to hardline aluminum-wall cable TV coax... 
this is what I used-- I haven't tested it out, but an earlier post seems 
to confirm that it has comparable efficiency to copper tubing, despite 
the fact that it's aluminum... 
	you can wind helical primaries easily at the Cable TV yard-- use 
an empty spool, say 18 inches in diameter, and use some brute strength to 
fix the cable and wind it properly-- up to 1 inch diam coax can be wound 
this way-- I'm still trying to figure out how to do a pancake with the 
same idea
	Good luck to those of you on small budgets-- It's tough, but it 
pays off.. so far I've only spent around 55 dollars on my form, coil, 
primary, NST power supply, and caps-- most of the stuff I have been 
scrounging for free.  This includes nearly everything except the HDPE 
form, secondary wire-- which I purchased at a junk yard for $1/lb, and 
the copper tubing.  
	Thanks again to Chip and all-- the list has helped me get a foot 
in the door-- although the theoretical aspects of the science have been 
getting past me.