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Re: Toroid made easy
Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>
A very clever idea Gary.
Can you provide some photos to Terry so he can post them in the archives?
Dr. Resonance
I cut 2 pieces of .040" flat steel into a donut shape. Donut is 20"
outside diameter with a 6" diameter hole. Metal plates are welded
together along the outside and inside edge only. A very small pipe
fitting is welded to the surface of 1 sheet of metal near the
center. A 5 lb. bag of charcoal is ignited and given enough time to
turn the 2 metal plates red hot. Air is slowly blown into the
fitting and the red hot metal is blown up like a balloon. The flat
metal will blow up into a toroid shape it is sorta like blowing up a
car tire innertube. Let it cool. Grind the welds smooth and reweld
if needed to make it smooth. You can also do the same thing to make
a sphere. I did the same thing with two 20" circles no donut shape
this time it made a very nice sphere. It only takes a few minutes
for the metal to turn red hot so the charcoal is basically
wasted. It would be good to make about a dozen toroid and sphere
parts get them all welded together and heat them red hot one by one
it would not be so wasteful on charcoal. I have not tried any
really large ones yet but I see no reason someone couldn't cut out
some 48" donuts shapes to make a large toroid. When the metal blows
up like a balloon the outside diameter gets smaller. You can get a
98% accurate idea of the actual size by bending a sheet of paper
into a radius to see how large your finished balloon shape toroid will be.
Gary Weaver