On thinner metals, I think starting in from the edge is good practice. A lot of tig welding machine give a burst of amps for a micro second to start the arc before settling down to a very low amperage.  starting the arc inboard a little helps to prevent blowing away the edge.

I wouldn't say a lot compared to how much spatter you can get with settings that are really bad.

The clips where a push angle was used seem to have more spatter. 

Since I was running the camera that day, I don't remember thinking that was undercut. Most likely just some residual slag that gives the appearance of undercut since the root was not wire wheeled . Camera angles and lighting can make a big difference.

thanks for the comment Brian,

jody

Super nice design

Hey Jeff, Roy is not available but I will chime in as best I can.  I have used solar flux on a paper mill shutdown on stainless open root pipe and it was just a mess.

About all you could say was that it did prevent complete sugaring of the root but welded like mud.   We were not able to remove the residue from the inside but judging from how hard it was to wire wheel the root pass before welding the hot pass, I would imagine it was be difficult.  High temp flux for silver solder is like that too unless you can soak the part in warm soapy water.

So I guess bottom line is that I dont think solar flux would have worked well for Roys job shown in this video,

hope this helps, 

Jody

Hey Lloyd, enjoyed speaking with you on the phone the other day... I don't have any experience with using Oxygen for plasma cutting but maybe we can flush some information out in future podcast calls.

Thanks, Jody

Agree with that 100%.  codes and specs like B31.1 are too vague on gap for socket welds

I would say it’s the gas. 98/2 would seem to call for spray transfer and 75/25 or pure argon won’t achieve a smooth spray

you are correct.  use gmaw mode with knurled rollers but dont tighten too much. JD and I made a video quite a while back using a lincoln 210 mp along with .035" dual shield wire using 22.5 volts and 310 wire speed.  That was for a 6 inch schedule 80 pipe fill and cap uphill so those would be some pretty good settings to start with for .035" DS wire.

75/25 argon/co2