Gooferking Science - 13-3-2016 at 13:34
I am working on building a high vacuum system and I need to secure some stainless steel joints. I know TIG is the way to go in this situation, but a
TIG welder is not readily available to me. Is brazing acceptable in a high vacuum (e.g. 1x10E-6 Torr)? If so, what solder alloy(s) can be used? I
didn't know if it would have any outgassing or virtual leak problems and I want to make sure before I make an expensive mistake.
Heavy Walter - 13-3-2016 at 13:52
Hi
I used to braze oxygen free high conductivity copper exhaustion tubes in order to evacuate and seal-off power electron tubes.
That was done with eutectic Silver-Copper alloy, without any flux (forbidden in high vacuum systems due to contamination).
Also I brazed SS tubing with silver-copper alloy but the melted metal doesn't flow so easily as in copper. The torch was regulated in order to get a
slightly reductive flame, that was cleaning the area of oxides.
In case you need to use a flux, then after cooling, scratch and wash with hot water.