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Doug Ayen

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Baitcon [Jun. 29th, 2011|03:41 pm]
Doug Ayen
I had a great Baitcon, but will be needing to retool for next year:

1) Zod, a 30 liter dewar last pumped down in 1992, has finally lost his vacuum, and needs to go to the cryogenics hospital to have the contaminating air removed from under his skin. I'm hoping to avoid shipping it due to the likelyhood of damage, best lead I have so far in the DC area is to check with Robert's Oxygen and see if they service them or know of a local company that does, otherwise I found some companies online that look like they'd be able to do it, but would need to get quotes and figure out transport.

2) my white gas 2 burner stove has finally died. I've already rebuilt the pump and burner assemblies, looks like the generator and venturi are at fault now . .. . aw, frack it, new ones are cheap.

Thank you all who attended, helped out, or otherwise assisted in making it a great Baitcon.
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Comments:
[User Picture]From: cz_unit
2011-06-29 07:53 pm (UTC)
I wonder if air products group could service it. Likewise one could pick up a couple of tanks of N20 and use that as a "filler gas".

Hm.

C
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[User Picture]From: blackanvil
2011-06-29 08:27 pm (UTC)
Possibly, though Air Products isn't local. I heard an anecdote on the machinist's list about how one desperate grad student once filled the hollow walls with CO2 and let the lN2 freeze it down to get his vacuum -- messy, inefficient, but it worked for a few hours. I suspect N2O would do a similar job.

If I'm absolutely SOL, I've got a PDF of the procedure and can rig up a high vacuum pump and a cold trap, but it would be really fracking annoying to do so.
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[User Picture]From: cz_unit
2011-06-29 11:55 pm (UTC)
How much vacuum do you need? A simple air conditioning pump can bring it pretty close to 30, is there that much insulating difference between vacuum and almost vacuum?

I guess if you really want to go for it we could rig up some mercury vacuum pumps. Been awhile since I have played with one of those.

C
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[User Picture]From: blackanvil
2011-06-30 03:31 pm (UTC)
I'm not exactly sure -- from what I've been reading, it seems that a very hard vacuum, 100 millitorr or less, is preferred, but since the loss of insulation value has been declining very slowly over a long period of time, I suspect that a lesser vacuum would work fine. Zod didn't come with a manufacturer's label or owners manual, and I suspect was jigged up in a cryo lab a long time ago.
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