[time-nuts] Re: hydrogen rich environment and oscillators

[ed breya]

If anyone is actually serious about small-scale experimenting with 
fairly high pressures possible, a proper pressure vessel should be used, 
rated high enough. One way to DIY a small tank with internal access, is 
with pipe fittings. The cheapest is probably galvanized steel or black 
iron. An assortment of say, 2 inch NPT nipples and fittings can make all 
sorts of containers and plumbing line attachments. A plug or cap at one 
end can serve as the access door to the chamber. It won't be hermetic, 
but that's not necessary for this situation.

You can use electrical feed-throughs - like the kind for RF assemblies 
with bypass caps and such. They can be mounted and sealed easily in 
gooped threaded holes.

I think feed-throughs and almost every standard connector type are 
available in hermetic sealed versions, but fairly spendy. I always save 
these kinds of things from salvaged stuff, and have a pretty good 
assortment in stock. I also save any junked metal semiconductor packages 
like stud-mount rectifiers and TO-3 etc transistors, for their 
metal-glass seals. I especially have a lot of axial lead end-caps from 
old shot or damaged hermetically sealed capacitors - they are easily 
un-soldered from the body tube.

It's best to of course have the smallest practical volume for minimal 
energy storage. If there's any doubt about the vessel, whether it's 
home-made or commercial, you can add safety margin by packaging it up 
with wrapping materials and outer enclosures to absorb energy and trap 
the chunks if something does go wrong.

I recently built a refrigerant recycling machine for R134a from junk 
parts. I needed to proof it and adjust the safety relief valve, so I let 
the compressor pump air to 450 PSIG where I set the cracking level. The 
most dangerous part is the receiver/oil separator, a small cylinder 
about 10-15 cubic inches, made of thin sheet steel. It's a real thing, 
rated 300 PSIG, but used and maybe forty years old. I set it up with the 
cabinet top in place, pushed back slightly to access the relief valve, 
while still covering the receiver, and I wore safety goggles and 
earmuffs. It worked out beautifully, and once it was proofed, I could 
safely pump it to around 250 PSIG for leak testing while all opened up 
(still with protective gear on).

Ed