how many passes do you guys make on your manifolds and whats a pass?

 

a pass is a weld bead. one pass would be laying one bead down. root pass means no filler used. most do either 1 or 2. when doing 2 first root, then add filler.

 

Correct.

Incorrect. Root pass just means the first pass. generally this is a full penetration weld. Filler may or may not be used on a manifold welds. On "real" pipe 99.999999999% of the time filler must be used.



Do a little more searching OP. This thread has been posted before and usually turns into a huge argument about passes, backpurging etc and so on. There has to be at least 2-3 threads in here that will lay out everyones opinion on the matter. You'll have to gleen what you will from them as no one ever agrees.

 

99% of the time, on a beveled pipe weld for a manifold, as long as the fit-up is good and both pieces of pipe are touching all the way around, I will make a filler-less pass just to fuse it then I will do a finishing cap pass with filler thats raised just above the material in height.

And no, I do not backpurge. I never bothered to set it all up. I have only made about 9-12 manifolds, but I have NEVER had a single defect to this day.