Copper to stainless Tid welds

[metalhoseguy]

Is it possible to weld copper pipe fittings to stainless? I have a client who is currently using silver solder for this joint. A TIG welded joint would be much faster and cheaper. Thanks!

[hotrodder]

This came up on a different forum a while ago. Getting enough heat into the copper without cooking the stainless may be difficult without preheating the copper. A nickel (erNi-1) or CuNi (erCuNi-7) filler can be used. Can also join the two alloys with aluminium bronze

[obewan]

Originally Posted by metalhoseguy

Is it possible to weld copper pipe fittings to stainless? I have a client who is currently using silver solder for this joint. A TIG welded joint would be much faster and cheaper. Thanks!

Don't even go there for a weld. Copper and stainless form an alloy that will experience severe cracking if welded.

We do join it using silicon bronze rod (Everdure) and it is actually more of a brazing process. We do use TIG but were unable to join copper to stainless without cracking until we used that filler wire. I don't know if it would work on a pipe fitting though. Maybe you could get it to flow with a fuel torch and by treating it like a conventional braze process, but then why not just use silver braze alloy?