Transfill from CGA-540 to 1/2-20UNF?

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mathematics

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I have the oxygen over here, and I need to get it over there. An ancient problem, plaguing divers since the dawn of time. I need to transfill to a vessel fitted with 1/2-20UNF threads, from one with a CGA-540 valve. Ideally, I need a gauge and a pressure bleed off. It's 100% O2, and yes, everything is O2 clean.

What are my options? Thanks.
 
Deluxe Argon Transfiller

Basically make that with CGA-540 on one end, and 1/2-20 on the other. Quite simple to make. Mine have Swagelok QF4's on them so I can swap around to different connections

What sort of hose should I be looking for, and what do I call the block for the release and gauge fittings? Thanks.
 
What sort of hose should I be looking for, and what do I call the block for the release and gauge fittings? Thanks.

oxygen compatible hoses are typically stainless steel braided with a PTFE core and either stainless or brass ends. Can get them from McMaster Carr or most hydraulic stores. Get it with 1/4" NPT fittings.
The T will be a standard brass T that you'll have to O2 clean before using.
 
oxygen compatible hoses are typically stainless steel braided with a PTFE core and either stainless or brass ends. Can get them from McMaster Carr or most hydraulic stores. Get it with 1/4" NPT fittings.
The T will be a standard brass T that you'll have to O2 clean before using.

Alright, so I need to go get a PTFE lined stainless hose with 1/4" NPT fittings, or should I get the swagelok QF4's instead? Then I need a CGA-540 -> 1/4" NPT adapter and a 1/2-20UNF -> 1/4" adapter? And somewhere in there I put a T block with my gauge, right? Sorry if this seems very basic. I may need some explicit direction.
 
Alright, so I need to go get a PTFE lined stainless hose with 1/4" NPT fittings, or should I get the swagelok QF4's instead? Then I need a CGA-540 -> 1/4" NPT adapter and a 1/2-20UNF -> 1/4" adapter? And somewhere in there I put a T block with my gauge, right? Sorry if this seems very basic. I may need some explicit direction.

The QF4's go onto the NPT fittings, are quite expensive, and only really recommended if you need that one whip to be used on different type of fittings.

You WILL need a needle valve though to control the fill rate. What do you have that uses a 1/2-20unf?

What I would realistically do if you aren't that familiar with this kind of stuff is do the following.
Call Northeast Scuba and talk to John. Tell him Tom Nelson sent you over there.

Tell him that you need one of these, but with a 1/2-20UNF fitting on the end *make sure to specify male or female* and tell him what you're doing with it. He won't be much more expensive than trying to DIY it, but if you aren't familiar with this kind of stuff, the extra $40-$50 is going to be worth spending. He can get the hose length however long you need it as well.
Standard Mixing Whip
 

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