purging stainless tube

[t51rsupra56]

I tacked a few peices of stainless tube together and can see thw sugaring that the lack of purge has caused. I am going to purge it when I get my second gas cylinder. My question is when I do purge should I just continue to weld or should I cut the pieces apart, grind the sugering off and re-tack them with the purge? Also how would I calculate for proper flow rate for the purge? thanks in advance

 

[Paul G]

You should cut the sugared weld out and start again with clean edges.

I run 6 lt/min to start with, and if I have several welds in the same fabrication (e.g. car manifold)
this can be turned down as the job progresses.

This is assuming joints are tight with no gaps.
If you have gaps then cover with masking tape and peel off as you weld.

Paul G

Edit to add.
Just spotted your location. That will be 12.5 cfh

 

[Robotstar5]

I tacked a few peices of stainless tube together and can see thw sugaring that the lack of purge has caused. I am going to purge it when I get my second gas cylinder. My question is when I do purge should I just continue to weld or should I cut the pieces apart, grind the sugering off and re-tack them with the purge? Also how would I calculate for proper flow rate for the purge? thanks in advance

Why not use a "Y" connector in the gas line? - link

...and welcome to the forum.