RE: Van de Graaff generator safety question (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 01 Jan 2004 20:46:04 -0700
From: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: RE: Van de Graaff generator safety question (fwd)

One could perhaps just use a power belt sander and just grind the whole
thing too.  Belt sanders can be awesome tools in crazy hands %:-))  But
gotta watch the dust with all those odd metals in it...

The waterjet guys here just blasted $500,000 into a new machine that has a
six axis articulating jet.  It could cut the hole while maintaining the jet
at 90 degrees to the surface.  Projects like this give them that big toothy
grin as they contemplate how they will program the beast!!  Water jets has
zero heat, 10mil accuracy, smoothed edges, and only about 2 pounds of force
on the work...  It would probably come right off the machine ready to
install...  30 mil super hard stainless would cut like "air" in that
puppy...  They are pretty cheap, especially on "cool stuff" that they can
brag about doing ;-))  In this case, they could do a little sphere first
and I would just let them keep it for their demo collection.  It would be
perfect to show off the advantages of their new toy!!  Such things make
them real friendly when it comes to price ;-))  I don't have any good
welding contacts, but I try and keep the waterjet folks as close pals these
days ;-))  It would be fun just to give them a "challenge"!!

BTW - If you have never seen a waterjet cutter do it's stuff, it is a "must
see"!!  A 30-mil jet of water with garnet powder added to give it cutting
bite.  The water stream travels at about a mile a second (5 times the speed
of sound!) at 65,000 PSI driven by about 40HP!!!  It can cut 8 inches of
mil grade titanium!!! and everything lesser...  Pretty scary machines to
watch!!  I have used them to cut 6-4 military titanium which is super hard
and accurately cut sorbothane which is super soft...

I do wonder if the sphere has any intrinsic stress in it that would cause
it to distort if cut.  I worry that it may start to squirrel if heat is
used.  Just have to try and see for such questions...  Cutting the sphere
is starting to get almost as much fun as the Van de Graaff generator itself
;-))

Cheers,

         Terry



At 08:06 PM 1/1/2004, you wrote:
>Original poster: Steven Roys <sroys@xxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Wed, 31 Dec 2003 19:53:08 -0800
>From: Dave Halliday <dh@xxxxxxxxxxxxxx>
>To: 'High Voltage list' <hvlist@xxxxxxxxxx>
>Subject: RE: Van de Graaff generator safety question (fwd)
>
>Find a welder with a plasma cutter - these puppies use an electrical arc
>and a blast of compressed air to make __very__ clean cuts in any ferrous
>metal.  The cut line is about 1/8" wide and there is zero spatter.
>Great stuff!   The same welder probably could use some computer work or
>they may need to have some electrical widget built so the options for
>trading are good.
>
>You could help them a lot by prepping the sphere - a lazy susan and make
>a plywood disk with a hole cut in it and some double-stick foam tape to
>secure the sphere.  Make it such that you only need to walk in there and
>the welder only needs to hold the cutter in one place while the sphere
>is rotated underneath.  Should only take about 15 minutes max.
>
>Google plasma cutter and you will turn up about 20K entries...
>
>
>
> > -----Original Message-----
> > From: High Voltage list [mailto:hvlist@xxxxxxxxxx]
> > Sent: Wednesday, December 31, 2003 4:54 PM
> > To: hvlist@xxxxxxxxxx
> > Subject: Re: Van de Graaff generator safety question (fwd)
> >
> >
> > Original poster: Steven Roys <sroys@xxxxxxxx>
> >
> >
> >
> > ---------- Forwarded message ----------
> > Date: Wed, 31 Dec 2003 11:20:41 -0700
> > From: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
> > To: High Voltage list <hvlist@xxxxxxxxxx>
> > Subject: Re: Van de Graaff generator safety question (fwd)
> >
> > Hi Ed,
> >
> > It is rock hard stainless steel, Probably need a grinder like
> > a cut-off wheel in a dremal tool or die grinder.  Forget a
> > hole saw unless it has cobalt alloy teeth no normal saw or
> > drill bit will touch it.  Once cut, a belt sander can finish
> > the edge.  I'll probably try it all an a little cheap one
> > first.  If I were really desperate, I would have it waterjet cut.
> >
> > Cheers,
> >
> >          Terry
> >
> >
> > At 10:07 PM 12/30/2003, you wrote:
> > >Original poster: Steven Roys <sroys@xxxxxxxx>
> > >
> > >
> > >
> > >---------- Forwarded message ----------
> > >Date: Mon, 29 Dec 2003 14:29:54 EST
> > >From: Esondrmn@xxxxxxx
> > >To: hvlist@xxxxxxxxxx
> > >Subject: Re: Van de Graaff generator safety question (fwd)
> > >
> > >In a message dated 12/27/03 2:05:27 PM Pacific Standard Time,
> > >hvlist@xxxxxxxxxx writes:
> > >
> > >
> > > > Hi All,
> > > >
> > > > Many thanks for everyone's thoughts!!
> > > >
> > > > I will go ahead and build the thing.  It sounds just about right
> > > > safety wise.  Not a toy by any means, but not like a case of
> > > > dynamite either.
> > > >
> > > > It sounds just about right :-))
> > > >
> > > > Cheers,
> > > >
> > > >     Terry
> > > >
> > >
> > >Terry,
> > >
> > >What is your top load (sphere) made of and how do you plan
> > to cut the
> > >hole to mount it?  I have a similar sized stainless steel
> > (gazing ball)
> > >sphere but I have thought how difficult it would be to use a
> > hole saw
> > >to cut a 3" or 4" hole in it.  Heck, it is difficult just to drill a
> > >hole in one of these things.
> > >
> > >How about a belt?  What do you plan to use?
> > >
> > >Ed Sonderman
> >
> >
> >
> >