Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Nifty hi-tech fusor chamber
Date: Sep 14, 1:14 pm
Poster: Richard Hull

On Sep 14, 1:14 pm, Richard Hull wrote:


I finally bit the bullet and ordered a hi-tech, professional all stainless steel vacuum chamber system. Mostly as pieces-parts from three different sources to be assembled later.

I was fortunate to locate a NOS (new old stock)10" varian, conflat full nipple. For those not familiar with vac stuff and tech speak. The nipple is a short stub length of stainless pipe designed to close a vacuum system or join a short gap in same. Each end of this pipe will have a conflat type vacuum seal flange on it. The Varian conflat fitting is industry standaard and uses knife edge crushed OFC copper gaskets to make an ultra high vacuum seal. they are all very expensive and range in standard sizes from 1.33 inch to 12 inch outer diameter. A 10" conflat nipple involves 8" diameter pipe, and so on.

The little 8" long nipple I got would normally cost ~$1100.00, but O.E. Technologies sold me one for $275.00.

I had to go for list priced 10" end flange "blank off" plates at about $205.00 each (2 required) OUCH!

I will have a beautiful 8" diameter by 8" long vacuum chamber that will rival the best on earth though, and won't have to worrry about outgassing elastomers, greases, epoxies, etc. I will machine my own 4" viewport window collar and obtain a 4/14" diameter, 3/8" thick pyrex disk window from Mc Masters for about $25.00. When all the smoke clears, I will have about a kilobuck invested in the chamber, fittings and window.

I have bell jar systems which are fine, but since I used a tantalum inner grid on my latest systems, the brown deposition layer on the glass will not yield in cleaning efforts to muriatic acid (hydrochloric) the way the old stainless steel deposition film did! It is almost impossible to remove the tantalum deposits from the glass! I find I have to polish the glass with alundum/water mix and a lot of elbow grease for hours to remove the last traces of the deposit. With a small, flat, removable end window, the process will not be as time consuming or frustrating.
Also, an all stainless chamber is bakable to allow the removal of most adsorbed gases.

This has ratched the fusor up to the next level in both cost and complexity.

Richard Hull