Alternative Toroid Idea

["Alexander Rice" <alexjrice-at-hotmail-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

    Hi all, i was reading the messge regrding fiberglass toroids and thout some
people might be interested, esp. small coil builders (like me). I have some
experience of fiberglass and belive me, it's hard work, espescially making,
polishing, waxing, coating with release agent etc. the moulds!
 
    For my small coil i used a piece of high density foam (this can be bought
from builder merchants for use as an underfloor insulator in sheets about 2"
thick and spray mounted together) i cut it to a rough circle and made a small
hole throught the middle. I then mounted on my lathe by gripping a longish (6"
ish) screw in the chuck and cutting a circle of plywood with a hole in to stop
the chick squashing the foam infront of the chuck. Used a bolt and a large
washer on the oter side to hold it in place (so the order is
chuck-plywood-foam-large washer-bolt-(you))  I then shaped it using 120 grit
sandpaper over a metal block to keep me steady and to even out bumps. having
got it to a 'pseudo toroid' i curved it under with some sandpaper round a
stick. This was then covered with al foil. It sounds cack handed but it worked
quite well. Ordinary polystyrene foam works too but dents really easily. This
is a wood lathe with a head that swivels so i could make on of these a few feet
in dia, and fully intend to for the nest coil. Sure as hell beats ducting!
 
Just in idea
 
Alex