Search found 8 matches

by Justin Fozzard
Thu Sep 13, 2018 9:35 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Victoreen 450p question
Replies: 9
Views: 2384

Re: Victoreen 450p question

A few years ago I worked for a company that made magnetrons, TWTs, thyratrons and other high power RF tubes. Many of the tubes were evacuated and then roll sealed using a hydraulicly operated tool. The seal had a blob of solder added afterwards to protect the assemblers from being cut by the extreme...
by Justin Fozzard
Sun Jul 29, 2018 8:04 pm
Forum: Announcements and Site Administration Topics
Topic: Going Out On A Limb
Replies: 14
Views: 2037

Re: Going Out On A Limb

Doug Coulter has recently been active on his forum posting some interesting results:

http://www.coultersmithing.com/forums/

Regards to all,

Justin Fozzard
by Justin Fozzard
Wed Jan 03, 2018 9:34 pm
Forum: Vacuum Technology (& FAQs)
Topic: Taking a large diffusion pump apart.
Replies: 2
Views: 530

Re: Taking a large diffusion pump apart.

Thanks for your advice, Jerry, you were right. The aluminium top jet was stuck by oily gunk to the lower one and after some very careful tapping with a rubber hammer it simply popped off. The lower jets were held in by a screwed rod and quickly came apart so I can now start cleaning away the old oil...
by Justin Fozzard
Mon Jan 01, 2018 10:13 pm
Forum: Vacuum Technology (& FAQs)
Topic: Taking a large diffusion pump apart.
Replies: 2
Views: 530

Taking a large diffusion pump apart.

Hello and Happy New Year to you all. I wonder if anyone on the forum has dismantled an Edwards E012 diffusion pump? It’s rather large at 12” diameter and so far I have been a bit stumped as to how to take it apart for cleaning. The pump is for use with a large vacuum chamber that I hope to use for s...
by Justin Fozzard
Wed Sep 27, 2017 9:03 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Bonding Tungsten and/or Iridium?
Replies: 27
Views: 4591

Re: Bonding Tungsten and/or Iridium?

Here are some photos of the innards of a Hughes 250 Watt-Seconds impulse welder that I use for electrode welding. The capacitors are charged to a maximum of about 450V and are discharged into the output transformer using surprisingly small thyristors. Front Panel: Hughes Welder 1.jpg The supply and ...
by Justin Fozzard
Sun Aug 27, 2017 9:11 pm
Forum: Images du Jour
Topic: Homemade Diffusion Pump
Replies: 2
Views: 773

Re: Homemade Diffusion Pump

Hello Ian, The top jet is screwed onto a steel shaft that is in turn screwed into the centre of the brass base casting. The second jet is sits on a step turned on the outside of the inner copper jet tube. The jet tubes are silver soldered into annular grooves turned in the base casting. The lower ri...
by Justin Fozzard
Fri Aug 25, 2017 8:37 pm
Forum: Images du Jour
Topic: Homemade Diffusion Pump
Replies: 2
Views: 773

Homemade Diffusion Pump

Here is a photo of my attempt at building a diffusion pump as a 14-year old schoolboy. Homemade Diffusion Pump.jpg It was my own design based on a picture in an encyclopedia article. I never got round to testing the pump and don't know if it would have worked. I was given an old vacuum sputter coate...
by Justin Fozzard
Thu Aug 24, 2017 11:18 am
Forum: Please Introduce Yourself
Topic: Greetings from a shed in Essex, England
Replies: 1
Views: 390

Greetings from a shed in Essex, England

Hello, I’m Justin Fozzard, an electronics engineer from Essex, England. I’ve been fascinated by plasma physics since my early teens when I spotted a faulty neon sign in a shop window. A very thin glowing filament was writhing about inside a letter O and I wondered what was causing it. As luck would ...