Re: foil-covered inner-tubes for large toroids?

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

Original poster: "Bunny Killer" <bunikllr-at-bellsouth-dot-net> 

YUCK    inner tubes suck   go to McMaster Carr and get the aluminum duct 
pipe ( the same as the 4" stuff at Home Depot) 10 -16" dia   yes its 
expensive  but GAWD it makes a decient toroid ( just a tad less pretty than 
a 1000$+++ spun unit for about 75$)  I made mine from 3 sections of 16" 
tubing at 25 bucks per section ( 75$ + tape   ummm 4 rolls)
total expenditures  100$     ....  beats 1000+$

the 12" at 3 sections should run about 20$ per section...   60$ pluss 
tape...   80$ ? or so..

Scot D





Tesla list wrote:

>Original poster: sparktron01-at-comcast-dot-net
>Hi David
>
>-------------- Original message --------------
>
> > Original poster: DRIEBEN-at-midsouth.rr-dot-com
> >
> > Hi all,
> >
> > I've been thinking of an affordabale alternative to a large
> > pofessional spun toroid for a large coil. I've heard of sev-
> > eral ideas, including the chicken wire covered wood and styro
> > foam skeleton frames. I almost certain that my idea is not
> > original, but I was wondering what you guys thought of a
> > large inflated tractor tire inner tube covered in alumi-
> > num foil or tape. Of course it would be imperative that it
> > didn't leak and I know that the small inner tube lined pneumatic
> > tires (wheelbarrels, 2-wheel dollies, ect.) are notorious
> > for slow leaks. My 2-wheel dolly tires always have to be in-
> > flated before use if I haven't used it in a while. Hopefully,
> > tractor tire inner tubes are somewhat more dependable for
> > holding air as I'm sure a farmer wouldn't want to always
> > worry about his tractor tires holding air. Has anybody had
> > experience with this approach at a large toroid?
> >
> > Thanks,
> > David Rieben
> >
>
>Richard Hull used a very large inflated donut (may have been a kids
>
>swimming pool) on Nemesis originally.  Cold weather will cause a
>
>reduction in internal pressure, and the tape will sag...  :^C
>
>Best option was 4" (and larger ) flexible PVC drainage pipe available
>
>at Lowes, Tractor Supply, Home Depot, Agri-Suppliers.  Use a coupling,
>
>cover liberally with Al tape and go.   I've made several large toroids
>
>up to 4 x 42" this way and they work fine; plus if you drop or impact
>
>them they "usually" won't permanently dent.  FWIW.
>
>Regards
>
>Dave Sharpe, TCBOR/HEAS
>
>Chesterfield, VA. USA
>
>
>