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Re: COIL FORM FOR MONSTER BL COIL
Tesla List wrote:
>
> Original Poster: Jim Lux <jimlux-at-jpl.nasa.gov>
>
> >
> >
> > I'd use this technique again but would cut out little half round indexes
> > for the vertical pipes to seat (nice idea).
>
> Use a hole saw before you cut the big circle out of the sheet of
> plywood. When you cut the big circle, the almost half rounds will be
> just right.
> >
> > I've had no leakage problems with the black ABS pipe I employed but
> > would suggest, as in any HV application, testing the proposed plastic
> > for leakage losses first before committing it to your project.
>
> I'd use PVC, just for structural reasons. ABS DWV pipe is actually foam
> core with a hard surface and is easily deformed. Don't forget that if
> you put 1000 windings at 10 pounds tension on, you are talking about a
> total load of 10,000 pounds. It is easy to inadvertently collapse your
> form when doing big wraps.
Jim,
Thanx for the good tips above. PVC pipe is not easy to locate in 2 inch
or thereabouts diameters. They make some 2 inch thinwall for built-in
home vacuum cleaning systems but this stuff has insufficient strength.
The ABS I used was pretty strong and did not deform in my case, and it
was readily available. I've located some 2 inch diameter x 1/4 inch
wall fiberglass tubing at a surplus place in 12 foot lengths and am
contemplating making the long drive to score it for a large future
resonator. It would be absolutely ideal!
If one were lashing together a fairly big resonator in the 4 ft+
diameter range on a tight budget then the readily abundant 4 inch PVC
green drain pipe which many of us use for NST powered secondary
resonators might be a good low cost choice for the verticals.
Robert W. Stephens