RE: Torrid made easy

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Rich" <rdjmgmt@xxxxxxxxxx>

To all, this idea will work to a point. I have worked on this concept
myself when it was being developed several years ago. We started out
with flat plates and use nitrogen to form the plates, air will oxidize
the surface. On a small scale it goes like this, make a ceramic mold,
place a sheet of material between the two half's of the mold, heat in a
furnace until the metal you are using is in a plastic state, we used
6AL-4V. Apply nitrogen between and it will form the material into the
shape of the mold. We formed quite complex shapes. As this was improved
it was later put into mass production and was used on the F15-E and it
used today making the F-15's for Korea. At this time they use hi-temp
heated ceramic molds and large presses for some shapes and the blow up
with nitrogen for others. The torrid would be easy to make but the set
up and supplies would be a killer.

Rich, kd0zz


-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Thursday, February 02, 2006 7:38 PM
To: tesla@xxxxxxxxxx
Subject: Toroid made easy

Original poster: gary350@xxxxxxxxxxxxx

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