had time to think
going to say 8" sch 40 pipe mild steel
here is how I would do it
open root
3/32" land
1/16" root opening
15 degree bevel on each pipe
for 30 degree bevel total
1/8" 6010 root pass DCEP @ 110 amps ( amps depend on the machine )
1/8" 7018 hot pass @ 135 amps DCEP ( same as above)
1/8" 7018 for fill and cover @ 125 amps A/C ( if you have an A/C machine ) if not 120 amps DCEP
use weave or wash style for fill and cover
I know better people here will tell I am wrong and stupid
just my thoughts
sincerely,
Kent
edit: this is from a old timer...the youngsters can tell how it is done now....my ideas and work thoughts go back to 1970... and then they had came from the 1930's...and yes I did know James F. Lincoln and did test his first welder
2nd edit: just OAW
swap the root and land 1/16 for land and 3/32 for root opening
9 psi for oxy, 5 psi for fuel
#2 tip
1/8" filler E70
that is OLD school