Re: Winding primaries

To: tesla-at-pupman-dot-com
Subject: Re: Winding primaries
From: Ted Linney <tlinney-at-paradise-dot-net.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 20 Dec 1999 22:09:06 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme
Team
A really cheap and easy to use material for mounting primaries on is "plaswood"
This is a foamed PVC, very light, strong, good RF and insulation
characteristics,
cheap and avaialble readily from most plastic outlets. Comes in many
thicknesses,
can be cut and used just like wood. Glues very well with plumbers PVC cement.
Used with success for my own Tesla

Tesla List wrote:

> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>
> Hi Dereck,
>
> A very common and important question you ask...
>
>         Winding primaries takes some practice but here are my tips...
>
> I made a really nice primary with 1/4 inch copper refrigeration tubing from
> the hardware store.  It is a big thing and has about 20 turns spaced only
> 1/4 inch apart.  See the pictures at:
>
> http://www.peakpeak-dot-com/~terryf/tesla/experiments/modact/modact.html
>
> I have to make a new one soon too...
>
> Most people really like the 1/4 inch tubing for primaries.  For low to
> medium power (0-2000 watt) coils it is just right.  It comes in very nice
> packages and is easily manipulated.  I use 1/4 inch fuse holder clamps to
> connect to it with a simple snap on assembly too.
>
> This is how I built the big primary.
>
> First I got a large two foot diameter 1 inch thick round pine base form the
> hardware store.  It was meant to be used as a do-it-yourself table top.
> Any strong base would work but be sure it is STRONG.
>
> Next, I cut a bunch of support rails out of wood (I live in dry Colorado,
> you may want to use plastic in non desert regions).  I had enough supports
> so that the soft tubing would be supported every 6 inches.  The supports
> were slotted wood with 1/4 inch slots cut with a table saw as one piece of
> wood and then the rails were sliced out of that single chunk.  So I had a
> bunch of rails with 1/4 inch slots, 1/4 inch deep, and 1/4 inch apart.  I
> then drilled a hole under each slot because I knew I was going to lash the
> tubing down with nylon cord.
>
> I glued the rails to the large round table top being very sure to space the
> rails out a bit as I went around the circle so the tubing would lay as a
> spiral.  Lots of rulers and measuring here.
>
> I then took the brand new tubing, which comes as a nice coil, out of the
> box without disturbing the tubing much (cut the box away).  Starting at the
> center and working outward I just laid the tubing on the base and expanded
> the coil carefully and evenly until it would just drop into the slots.  I
> was very careful to do minimal bending and basically just unwound the
> tubing a little so it would expand as large chunks at a time.
>
> The tubing fell into place without kinks or other problems and I tied it
> down as I went.  There is 100 feet of tubing on mine, so I spliced it with
> a 1.5 inch piece of brass tubing from the hobby store with a torch and
> solder.  However, you can get the tubing in 100 foot lengths as a found out
> later.
>
> I have used this primary for two years and it is very durable and has a
> very large tuning range.  As the seasons pass the wood expands and
> contracts which broke some boards I had glued to the bottom across the
> grain of the wood for supports but the coil itself is holding up perfectly.
>  The tubing is tarnishing a little but nowhere near what my friends in
> humid regions see with coils turning green and all.
>
> I definitely recommend "going all out" and doing it right the first time to
> make something that will last a long time.  Most of my older primaries were
> thrown out due to poor construction rather than being the wrong design.
>
> Hope this gives you some ideas for yours...  I am sure others have more
> tips too.
>
> Cheers,
>
>         Terry
>
> At 09:09 PM 12/19/1999 -0600, you wrote:
> >Hi,
> >
> >This is going to sound like a dumb question, nevertheless: can someone give
> >me pointers on winding primaries, such as the flat Archimedes spiral or
> >suacer/bowl shapes? I have built a small TC a few days ago, my first, with a
> >flat spiral primary made of 10AWG bare copper wire. It doesn't make huge
> >sparks, but there's something about seeing your first coil work that feels
> >great. Anyways, the primary was a pain in the nether regions to make. If
> >anyone has any winding methods that they find make it go easier, let me
> >know. Thanks in advance!
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