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Re: Towards the autonomous lifter - electrostatic voltage generators.



Original poster: "Peter Terren" <pterren@xxxxxxxxxxxx>

When used in my 11,000RPM angle grinder for a spark gap, acrylic is prone to deformation and eventual shattering. Polycarbonate is a bit better but still prone to shattering. My 1/2 inch Tufnol laminate looks and feels rock solid by comparison and has lasted without problems.
http://www.bayplastics.co.uk/suppliers/Tufnol-supplier/prod-eng-tufnol(intro).htm


Peter

> Original poster: Robert Clark
> <bobbygc2001@xxxxxxxxx>
...........
CAUTIONS!
Note that on the Powerlabs page they were attempting
to cause a CD disk to disintegrate by spinning at the
highest speed of the Dremel. In *this* experiment they
had to additionally strike the spinning CD with
another CD to get the spinning CD to shatter. But
there have been cases where CD's have shattered at
lower speeds than 35,000 RPM. Acrylic if that is used
for the rotor probably would have comparable tensile
strength as a CD. It is *strongly* advised that the
rotor be gradually brought up to higher speeds
stepwise. And it is *strongly* advised that the rotor
be behind a protective wall during these experiments.
You can view the experiment by video camera or by
mirrors (metal so as not to shatter.) In the Powerlabs
experiments the experimenter held the Dremel with the
spinning CD out in front of him. This is strongly
disadvised.
 Note also if you use more than one rotor on a single
Dremel this could cause wobbling which could put more
stress on the rotors increasing the chance of shatter
and also making the directions the shards would go
more unpredictable.
 Also, if you increase the diameter of the rotors the
speed at the edge of the rotor is also increased
thereby increasing the chance of shattering. Moreover,
the Dremels are actually designed for rather small
diameter grinding attachments. Large diameter rotors
could damage the Dremel motor.


Bob Clark