By dbigkahunna
Date 03-21-2013 22:13
Edited 03-21-2013 22:20
Pretty much what he said. Be sure you have a good fat land on the pipe. Big land, big gap. The land holds the weld and the gap lets it get get in. If you do not have enough gap, you cannot push it in. If the land looks too big and the gap scares you, then you are pretty close. Find where you machine runs and leave the dad blamed thing alone. If you are doing the up 5 down 5 dance, you aint gonna make it. You should be able to run top to bottom. On 2 inch set your tacks at 12, 3, 6, and 9. Run from bottom to the side, break, feather the weld and run from side to top.
If you have too much gap you can always slow and turn down. But if it is too tight, you may as well spool up. I have tested a lot of welders on this test. Most will bust because of IP. And that is caused by too tight of a gap. You may blow a tack if you get it too thin, but if all you do is feather the start of the tack and leave the keyhole side alone.
Another thing is rod angle. The rod needs to be fairly square to the root opening. As you come up the side if you start tilting toward the low side you are going to undercut the bead. And they you are really screwed. You will never get it out and may never see it until you cut your coupon. And it can break on the 2 inch coupons as there is not much to polish off. And you will probably get a visual bust with the UC anyway.
When the coupons are set up properly and the welder does his part, you cannot tell where the tacks are and the only thing on the inside will be a little spot where the bead ties into the top tack. If you have to run this on 8 inch sch 80 with a 1/8 rod use more heat. And THAT gap will scare the bejebbers out of you.
Don't let it intimidate you. Just keep the gap and land wide and the heat low and slow. And if you bust it, you are in a long line of very good welders who have done the same.