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Does this look sufficient for a proof of concept fusor?

Posted: Sat Jun 09, 2018 8:05 am
by Rajko Injac
I'm curious as to the viability of this desert bell as a vacuum chamber for a very basic design, no star mode or any research capability. I attached pictures to the post. Any input is greatly appreciated.

Re: Does this look sufficient for a proof of concept fusor?

Posted: Sat Jun 09, 2018 3:32 pm
by Richard Hull
Glass bell jars are never a great option due to implosion hazards. However if the walls are thick enough and the glass is pyrex or Kimax (boro-silicate) then a simple, low power fusor is very possible. I certainly used a pyrex bell jar back in 1997 on fusor II for an advanced demo device. I will admit that I pushed it a bit far. When the glass chipped a flake off during a run, I never ran that bell jar system again and moved immediately to fusor III an all stainless steel system.

Folks have indeed used all manner of non-pyrex little jars and survived the experience. I would not recommend it, though.

Richard Hull

Re: Does this look sufficient for a proof of concept fusor?

Posted: Sun Jun 10, 2018 7:14 am
by Rajko Injac
Thanks for the reply! I plan on sticking it to a piece of wood or the like with the grid attached. What pressure would you recommend? I have an improvised protective screen so implosions aren't too much of a concern, given, I'd rather not have to clean up glass and expose myself to the gasses.

Re: Does this look sufficient for a proof of concept fusor?

Posted: Mon Jun 11, 2018 12:35 am
by Samuel Berman
Wood probably isn't the best material for vacuum work, but it might be ok for demo fusor pressures. Still, plastic would be better.

Re: Does this look sufficient for a proof of concept fusor?

Posted: Mon Jun 11, 2018 4:41 am
by Richard Hull
Wood is 100% out of the question and plastic is also bad. You would never pump it down to a decent glow range with wood, you would probably not even get a good spherical ball in the center using wood, unless you got a monster pump and pumped nearly forever. This isn't a wood shop project.

Richard Hull

Re: Does this look sufficient for a proof of concept fusor?

Posted: Mon Jun 11, 2018 8:43 am
by Dennis P Brown
Besides a base, you will need some type of gasket to form a 'soft' seal to the edge of your bell jar. That is critical for both a proper seal for vacuum and for safety. Cutting a ring of rubber like material to match the edge of your bell jar is rather easy.

A simple base would be a large enough piece of any metal plate as long as it is thick enough to not deform under vacuum. Metal has the advantage of being an easy ground point for your system.

Re: Does this look sufficient for a proof of concept fusor?

Posted: Mon Jun 11, 2018 3:10 pm
by ian_krase
That Bell jar looks pretty thin edged. Doesn't that style of Bell jar normally have a think heel if meant for vacuum?

Re: Does this look sufficient for a proof of concept fusor?

Posted: Tue Jun 12, 2018 4:33 pm
by Rajko Injac
It doesn't, it's a desert dish that i salvaged (don't tell mom).