Fusor Forums

I read that the lowest pressure attamiable with a 1399 is 1.5X10^-2 torr, this translates to 15 millitorr, or ~15 microns, correct?

I just want to make sure this pump will be capable of fusion pressures

Any mechanical pump is generally not ideal for fusion, regardless of low end claims. You have to have a secondary diffusion or turbo pump for easy fusion.

The 1399 specs are, for the most part, a joke and, even if real, those specs are for a brand new, off the shelf, mint pump! An old worn out single stage like the 1399 would never do spec. As a matter of fact, few brand new mechanical pumps will meet their manufacturers spec in a real, full vacuum system setup.

The only thing that's real and honest is your pump of choice, pulling through your system, being read by a well calibrated gauge. All else is pretty much sales pitch and floobie dust.

Get a two stage pump and pray it is OK.

Richard Hull

Call or visit every neon sign shop and also every testing lab that does helium leak detection.
Explain that you are doing a high school science fair project and can you have a old pump ?

I got my most excellent welch 1397 pump from a discarded helium leak detector. It pulled the fusor down to plasma extinction very easily.

FYI, when talking to the shop owners, avoid discussing fusion or neutrons or radiation-- it just make them think you are not serious or you are doing something dangerous. You might call it a high vacuum deuterium plasma experiment.

Thanks for the advice both of you
I'll start looking for other types of pumps, and keep my eye out for good dual stages

OK, I've come to understand how a good vacuum system is created, and that I need an oil diff pump (turbopump seems excessive)
I found this http://www.ebay.com/itm/Edwards-High-Va ... 3a70d29b51
some questions / concerns about this type of pump

1 it's watercooled, i can set up a watercooling system no problem, is that OK?
I know that most fusors prefer air cooled

2 I see no mounting flange... how difficult will this be to mount?

3 I see no visible baffle, will I need to install one?

I'm planning on a bell jar setup, similar to what Jeff Robertson has here- viewtopic.php?f=10&t=4156#p26546