Varnishing American

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Parpp807-at-aol-dot-com>

Hi All,
I am presently mopping polyurethane onto my new 48 inch bipolar secondary. The
power winder on the wood lathe worked just great and the #28 wire almost 
wound itself.

I need help in determining the diameter of the primary. When I made my 20 
inch bipolar
I experimented with different primary diameters using ordinary # 12 house 
wire. The
finished coil will be 3/16 copper tubing. The ratio of the secondary / 
primary diameters
 seems to be pretty near to 0.5, and anything much closer guarantees arcover. 
Is there 
an equation for this, or is it all trial and error. The OD of my primary is 
4.5 inches for the
sked 40 PVC. Any suggestions will be much appreciated.

I think I found a good method for making a form for large diameter primary 
helixes.  I got
a 50 ft roll of galvanized roof flashing at Lowes. It is very very springy. 
You can let the roll
unspring to most any diameter, say between 7 and 12 inches. When you set the 
desired 
diameter just take a strong tape, I use duct tape, and tape the roll. The 
walls are thick,
and the roll is heavy enuff to let you wind the copper tubing around the 
roll. The edges
are very sharp; let's be careful out there.

Cheers,
Ralph Zekelman