Vaughn:
Can't answer your question as well a most of the guys in this group.
Just wanted to say that I too grew up on C.L. Stong and 60's era Vacuum.
I recently purchased on Ebay a good Turbo Pump and controller for a crazy low price. I thought I might have to at least replace the bearings, but, it revs up just fine.
Tom M.
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--- In VacuumX@..., "Vaughn Mcdowell" <vaughn.mcdowell@...> wrote:
I am a baby boomer retired in my late 60's. When I was in high school I was experimenting with refrigerator rotary pumps as described by Strong in the Amateur Scientist articles. As a senior in high school I learned to blow Pyrex glass; during college in undergraduate and graduate I worked with vacuums systems but mostly for building Argon ion and N2 lasers. I did some diffusion pump work but very briefly. I remember using gum rubber tubing, stop cock valves, and Pyrex glass tube connections. Afterward I haven't touched vacuum systems until 2003 ( fired up my diffusion pump) but very briefly; and recently much more. I have always had a love for vacuum systems. But my vacuum world has changed significantly with quick disconnect etc. I feel like Rip Van.. Having limited funding I looked to Ebay for getting components that I could afford. I have been slowly acquiring KF fittings for future use. In the meantime I am using what I know to get by with. "Procedures in Experimental Physics " Strong has been my Bible. I have acquired more recent Varian training manuals; info from Bell Jar; etc.
When I was in College McLeod gauges were used for reference; now I have very limited vacuum references; the gas discharge method; the TC gauge and Ion gauge method. The first method is very dangerous in the 10 micron and below:
I have abandoned this method; in the future I have some high voltage experiments in mind: .
The TC gauge is limited but I am mainly interested in some ball park idea; I have purchased several DV-6M types new and used; I can used the hysteresis factory data to get some reference but how do I know if is new that some oil back streaming hasn't changed or shifted the thermodynamic continuity flow equilibrium much less the non linear characteristics? When I started testing my diffusion pumps the TC controller would quickly peg below zero; I started zeroing my TC controllers using the diffusion pumps. At the moment I feel like I am working in the dark. Even if I were to use a calibrated TC gauge; how do I know mechanical and diffusion pump back streaming won't significantly affect its thermodynamics significantly??
Thanks
