Has anyone tried this?

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
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JamesBroussard
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Has anyone tried this?

Post by JamesBroussard »

While searching for a diffusion pump to purchase iv noticed how simple they are internally... my question to you guys is has anyone made one? how precise do the jets have to be?with size variation what can be measured from a small one to larger one(higher vacuum achieved/pump speed etc...)?

anyways i have a friend with a machine shop and usually a descent amount of free time when not in class or at work so let me know what you guys think.

other thought - http://www.belljar.net/fbleediffpumps.pdf


I'm up for trying to make anything if you can save money
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Richard Hull
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Re: Has anyone tried this?

Post by Richard Hull »

Make one!!!??? Sure you can. These are very low precision systems. However, Make one!!!??? These things are too cheap surplus to ever consider making one. I have seen several "build your own" diff pump articles in my past and youth, but this was when they were expensive. Today, many folks are hard pressed to give these things a good home for free.

Admittedly, most diff pumps ever made are now in land fills as few if any modern systems are designed with them and most of the older systems that used them are long torn apart. Still, there are deals to be had in used diff pumps...cheap.

If you like make busy work, feel free to roll your own.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Steven Sesselmann
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Re: Has anyone tried this?

Post by Steven Sesselmann »

James,

A skilled glass blower can make these from glass too, very simple, you just heat the oil with a bunzen burner.

http://www.asgs-glass.org/asgs/GTR/PROJ ... ojects.htm

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG
tligon
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Re: Has anyone tried this?

Post by tligon »

Yes. The Virginia Tech Chemistry Department used to have a glass-blower who could crank out a working oil diffusion pump in a few hours. They were a specialty of his. If you ordered a glass system built, it was likely to have a diffusion pump whether you asked for one or not!

He put in a pair of electrical feed thrus and ran a coil of heater wire in the oil reservoir, IIRC.
JamesBroussard
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Re: Has anyone tried this?

Post by JamesBroussard »

Well then, i didn't realize this.. most iv seen are for around $200+, would be fun to make but otherwise wheres a good source? and whats a good size? guess ill have to weld a new flange on the bottom also,.. polished the whole thing today... looks really shiny







what if i made a turbomolecular pump....
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Carl Willis
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Re: Has anyone tried this?

Post by Carl Willis »

Hi James,

Try calling Cindy Lee at LDS Vacuum and seeing what she has in stock. They refurbish leak detectors and are very friendly toward hobbyists. The little leak detector diffusion pumps are perfectly adequate. Keep in mind that you will probably pay as much for the oil (DC-705 or Santovac) as you will for the pump. Also keep your eye on eBay for a few weeks. $100 is the most you should pay for a 2" pump in good condition.

Nothing wrong with building one, but don't do it just to save money because you won't!

-Carl
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JamesBroussard
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Re: Has anyone tried this?

Post by JamesBroussard »

Thanks for the heads up guys, ill contact Cindy and keep an eye out on eBay.
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Carl Willis
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Re: Has anyone tried this?

Post by Carl Willis »

Watch for the Edwards Diffstak 60s and 100s. Edwards' warehouse in England has been selling these off on eBay for "best offers" of under $100, and they are brand new and come with a manual. The downside is the exorbitant shipping to the US by Royal Mail. The Edwards EO50/60 is a leak-detector pump I use and recommend. I got one from Cindy Lee and have gotten others on eBay. This has the more affordable NW-50 flange.

-Carl
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JamesBroussard
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Re: Has anyone tried this?

Post by JamesBroussard »

yeah i see a few.. like Edwards Diffstak 100 $86.00 + 85.00shipping

but i think i'm getting alil ahead of myself unless i can get the pump from school :S
jdgertenbach
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Re: Has anyone tried this?

Post by jdgertenbach »

See http://belljar.net/forum/index.php?topic=109.0 for recent discussion on home made diffusion pumps
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