Paul, My uncle used to work at a refinery and welded a lot of high pressure steam pipes. When welding pipe, he'd start with prepared ends that were Vee-d. First pass, he'd start a weld and then burn through and then continue the bead with little arc showing because he was laying a bead on the inside of the pipe. When done with the inside pass, there would be only a little bit of slag in the bottom of the vee as the weld was on the inside. He'd chip what little slag was showing and then make the second pass to fill the vee. Chip again and then put an outside pass that lapped over the filled vee a bit.

When welding pressure joints on a pipe, they will always burn a hole when finishing a stick. Fill that hole when starting with a new stick and continue on. Problem with a wire feed is the cold start when you first start the pass. Normally leaks there if it's going to leak.

This welding on the inside from the outside isn't really as hard as it sounds. I've done a bit but not really enough where my welds would stand hi-pressure steam. Also, like most skills I don't do enough welding on a regular basis to keep the touch. Normally do just enough to realize I'm rusty and when the project is finished, I've gotten back a little of my touch but now I'm done and it's time for the touch to get rusty again.