Valve for filling tubes with argon gas

The ebay seller (and link) Farny provided in his original blog post is long gone, but the high pressure valve Farny used appears to be a J13W-160P stainless steel needle valve with a pressure gauge and female threads.

These valves aren’t intended to be used as vacuum valves, but according to Ron Soyland the valves should be leak tight for the purpose of filling the tubes with gas.

Farny bought two brass adapters with a hose nozzle on one side with a 6mm hole, and a 1/4” male thread on the other. If the adapter is screwed directly into the valve it would leak, so Farny machined a PTFE washer that is pressed by the brass adapters into the body of the valve. This should form a leak tight seal.

Farny connected the valve to a KF-40 flange via a swagelok fitting. The copper capillary used was soft soldered into the adapter. It was twisted so it is more flexible, rubber hose could have been used instead, but Farny wanted to avoid plastics and rubber as much as possible (and I agree).