3 ms·
A number of things. Metal seals, welded and vacuum brazed joints, a variety of good epoxies. Even good O-rings. And helium leak chasers, so you can actually fin
by analog31 5y ago
A number of things. Metal seals, welded and vacuum brazed joints, a variety of good epoxies. Even good O-rings. And helium leak chasers, so you can actually find and correct leaks.
To get down below a certain pressure, you have to heat everything and "bake out" residual volatile materials. This precludes a wax from even being tested at the lowest pressures.
- MengerSponge 5y agoIf your system is cryogenic you can absolutely still use wax and wax-like products. I sealed an aluminum can for something like 30 LHe cool downs with a mixture of glycerine and soap. Future cryogenicists: glycerine+soap is amazing because you can wash it away with hot water before you finally take the part to get re-welded. Most epoxies/sealants can't be cleaned so easily, fouling any future welds.
- analog31 5y agoJust adding one more thing, I had very good lock with Swagelok Ultra-Torr fittings, which are an o-ring seal that works on either metal or glass tubing. This is how I managed the metal to glass seal when needed. I didn't do much glasswork, though. My dad is a retired research chemist, and he did all of his own glasswork unless it was something really tricky. If needed I could silver braze the Ultra-Torr into a larger object. It's just a bit of a puzzle to figure out what sizes of glass tubing mate with the various metal fitting sizes, because glass tubing sizing can be variable.