[TCML] Considering a new coil build...

bartb bartb at classictesla.com
Wed Mar 25 19:18:45 MST 2009


Travis Tabbal wrote:
> Sounds like I need to think bigger. I guess if I'm going to buy
> a nice pulse cap I may as well build the big coil while I'm at it though.
Cool! Bigger is better if you have the cap energy and power to back it up.

> Any thoughts on where to obtain flat copper strip in suitable sizes and what
> those sizes are? With 1/2" tube, the primary gets wide fast, and I can get
> the turn to turn spacing lower with strip.

I bought my ribbon here at 
http://metallectric.com/Tesla_coil_components.html
This was 32 mil ribbon 1" width and perfect for my SRSG coil. The price 
was good and it came in in excellent shape.
http://www.classictesla.com/photos/sisg/sisg-101208006.jpg

Here are a few pointers with ribbon. While purchasing G10 12" square 
discs for the RSG at McMaster-Carr, also purchase Garolite for the 
standoffs. Garalite is easily tapped, so you can mount with screws the 
standoffs to a base. Wood working skill saw is what I used to cut it. I 
set up a fence and a stop for the 1" depth. Pretty simple. Actually, 
with my standoffs, I first tried to cut strips in the bottom and top 
caps (1/2" each). This worked great for winding (which is why I did it), 
but it didn't work well when placing the top cap. The best way I found 
was to go ahead and slice 1" depth slots in the Garolite and use a 1/2" 
simple top cap. I did this on the later four standoffs.

The number of standoffs is important!!!!!!!   If you try to go with only 
4 stand offs around the coil, you'll be hardpressed to get it even and 
accurate. I had the hardest time with this. I finally broke down and cut 
four more standoffs for a total of 8. I was then able to manage 
something usable. If I were to do it again, I would use 8 total and cut 
them all for nice fit.

> How about holding the flying electrodes into the G10 disk?
David will have the best info for your here. I used tapped holes in the 
side of a G10 disc. Nothing ever come loose, but there was a study 
performed by a coiler on the possibility. It seemed then best to use 
collars on each side of the rotating electrodes to ensure the electrode 
is well set in place.

> For the toroid, going bigger means fabricating them. I have yet to make a
> decent looking dryer duct toroid. Any tips there?
For a bigger coil, then certainly a bigger toroid is needed. The best 
homebrew toroid I've made was to use corregated tubing and then to cover 
in plaster of paris and some other similar compound (50/50 ratio). After 
the goop dried, I sanded smooth and covered in Al tape then smoothed the 
tape out by rubbing the tape with a Craftsman 1"D socket. Came out 
excellent and felt as smooth as my spun 9 x 30 toroid. There are of 
course cages or ring toroids you could do. Since your toroid needs to be 
rather large, the later might be a better option for you.

Take care,
Bart


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