Can I Use Aluminum for DIY Diffusion Pumps?

[SupaVillain]

Can I make diffusion pumps from aluminum?

I am going to create parallel connected diffusion pumps for many UHV purposes. I see that aluminum that is treated to prevent outgassing is used for UHV valves, chambers, and reactors.

I'd like to know what temperature diffusion pumps boil their silicon oil at because I would love to make these pumps from aluminum. Diffusion pumps are superior in every way when it comes to low cost DIY. There are even DIY diffusion pumps made from stainless steel cups that are poorly designed (shooting vapor straightdown instead of onto cooled walls) on instructables.com that have achieved 0.022 millitorr. Because these can be combined in series or parallel, their strength does not matter.

 

[Quantum Defect]

You may have better luck buying a used/rebuilt diffusion pump, rather than building one yourself.

Duniway Stockroom is a reputable company for al kinds of vacuum hardware, including rebuilt pumps:http://www.duniway.com/catalog/dt-rebuilt.php

You can probably find old diffusion pumps on e-bay, as well, but I would be cautious, as you do not know what materials went through them.

The boiler temperature varies, depending upon the kind of oil being used. Check O'Hanlon, p. 228 for a table of T_boiler of some common types of diff. pump fluid. (ranges from 135 C [butyl phthalate] to 275 C [Santovac 5] )