Fusor Sputtering help

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Joined: Thu Aug 10, 2017 9:28 pm
Real name: Paul Beck

Fusor Sputtering help

Post by Paul_Beck » Thu Aug 10, 2017 9:33 pm

Hi, my name is Paul Beck, and I just today joined the plasma club! I built the typical farnsworth fusor in my garage, and I just tested it out today. I was elated when I saw some traces of plasma, but I was disappointed to see that even as I continued to dial the voltage up (up to 12kv), I still only saw a single arc of plasma from the inside grid to the outside grid. Weirdly enough, I only began to see plasma after 4kv (it should appear at much lower voltages??).There was some jumping and sputtering as the one single arc shifted around in different spots of the fusor, but I never saw a uniform grid of plasma surround the inner. Please help!

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Joined: Mon Nov 28, 2016 7:48 am
Real name: Ian Krase

Re: Fusor Sputtering help

Post by ian_krase » Fri Aug 11, 2017 1:47 am

Your first post should be in the welcome forum.


Pictures would help. (Although photographing glow discharges is difficult)

Do you have vacuum gauging (pirani or thermocouple gauge)? If not, you might have a really poor vacuum and not know it. This almost suggests huge leaks.

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Dennis P Brown
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Joined: Sun May 20, 2012 2:46 pm
Real name: Dennis P Brown
Location: Glen Arm, MD

Re: Fusor Sputtering help

Post by Dennis P Brown » Tue Aug 15, 2017 12:06 pm

Agree with the first poster. Sounds like you don't have a vacuum gauge; get one asap if not (a cheap thermo-couple and readout with cable) and determine your vacuum. That will make determining your problem simple to address. If you do, then post the reading so we can address the issue.

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