by Walt Oglesby
(Hahira, Georgia)

Im not struggling with my tig root pass but i know it can be better I've tried a bunch of different things and what works best is to go really really slow on about 100 with gas on 20.

My questions is how much "back bone" am i suppose to have on the underside of my weld.

My cap and root are very nice but there both flush with the metal. The worst part is that i can't get a straight answer about this.

I've been in college for about 15 months now just finished my tig 1 witch is a butt, lap, and tee in every position.

I'm taking tig pipe next quarter is there any tricks to that ?

Thanks sorry for the long message.


Flush or better satisfies some codes but the problem is the way people and inspectors interpret the codes. Most want a little reenforcement on front and back. especially for bend tests....so that you can grind off the excess and never have to grind below flush to smooth out the weld.

For tig pipe welding, the tough part on the root pass is getting the bottom 6 o clock position to poke thru like the top

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Jan 29, 2014
root NEW
by: Anonymous

Best results for a good root is dnt b scared to open the pip to a loose 1\8 or 5\32 gap,depends on what size wire u root it with. Turn ur gas and heat down take ur time and comfortably is the most important. I seen where one guy said uniformity is important he's rite its very important.

Aug 12, 2013
by: Anonymous

Between flush and 1/8" is acceptable. Most people prefer just above flush.

The real kicker is uniformity. If you're the same flush all around you're good to go. If the bevel edges show in spots, or you didn't fuse into the tie ins (pipe welding) then you're wrong.

Same goes with the cap. Though you want it a little bit over flush.. and UNIFORM all the way around the joint.

For TIG it really all depends on the metal. I run a stainless root on std pipe between 75-80 amps. Carbon is hotter. The cap I run anywhere between 105 and 130 depending on how fast I can go and how much room I have. But numbers don't mean a thing. Practice.

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