[Adam's Got Skills]

I trying to practice some tig in the garage an thought i would ask what some real welders think. Im working on 1/2" flat an I turned them to try an replicate a bevel. Im trying to practice open root tig. Since i don't have a pipe this is what i got. Since i don't have any back purge experience or equipment i just welded a couple pieces to bottom top and back of my joint then purge gas into the gap in the joint. I started at 85 for my root but after a couple inches turned it up to 93. I didn't take a pic of the root but i kinda decided to do this after my hot pass. So any ideas would be helpful thank u. Oh and Im at 100 for my hot pass. would u keep that amperage to fill an cap the rest out?

[Adam's Got Skills]

by the way its vertical up....right side is the bottom. Im using 3/32 2% thoriated and 100% argon

[TRACKRANGER]

Hi Adam

It's hard to tell from the photo but it looks like you have the plates at somewhere around 90 degrees to simulate your bevel. If that's the case, that angle is way too big, and you'll probably wind up with a lot of distortion/pulling in the weld.

Maybe 60 degrees inclusive would be a better choice (and require much less filler)

Hope this helps
Cheers
Trev

[Adam's Got Skills]

It's less than 90 degrees i knew i wanted 60 but to say it is 60 is probably a dubious proposition at best. Your probably right as far a it's probably off a lil bit. I did 3 more fill passes an I think I'll give it a rest for tonight. Oh Im also using 3/32 er70-s2

[Adam's Got Skills]

Is my heat good tho? Am i at least in the ballpark....Or at least playing the same sport??? I was using about 98 amps for hot/fill passes...90-94 on root

[Mongol]

Some thoughts:

Next time take a picture of your root pass before you run a "hot" pass. This will tell you/us a lot. If you do it right your "hot" pass should really only be a fill pass. Running your "hot" pass too hot could mess up your root; or fix it, it really depends.

I see undercut, but I don't think it's from running too hot (100 amps isn't a lot for 1/2in thick plate). You need to hold those edges a little longer in order to fill them properly. It also appears that you may be running too cold. You'll notice the toes of the weld don't blend well into one another. I'd suggest running a little hotter.

Are you walking the cup? Not a criticism, it just looks like you're trying to weave. But I also don't see cup marks. You can freehand a weave, but, personally, I get more consistent results from walking the cup to weave.

In all it's not terrible, but could be improved upon.

[TRACKRANGER]

Is my heat good tho? Am i at least in the ballpark....Or at least playing the same sport??? I was using about 98 amps for hot/fill passes...90-94 on root

For 1/2" flat I'd be going larger on the current, probably at least 120-130 Amps. Weld time will be less also. It looks like you've got no danger of burning through.

Try cranking up a bit and see if you feel the result is better.

Trev

[Otto Nobedder]

Adam,

There's been a lot of good advice.

To answer the original question, your root looks fine from this side. The picture I didn't see is the back side of that root. That's what tells the tale.

Steve S

[Adam's Got Skills]

Thanks guys...I'll try turning it up a bit tomorrow afternoon. I'll take a picture from the back when I'm done...I could probably do it now since I'm probably past the point of needing back purge. Oh and yes I was doing a hand weave....I found personally (not that I know anything) that I can key hole it dip a lil filler and the kinda weave to cover any gaps an to smooth it out to the best of my ability anyways. I have really no experience welding pipe personally, but I'd seen a bunch of stick pipe done...but I personally never got to do any. What kinda stuff can happen to ur root whether running cold/hot???? I'm really ignorant on this subject....any enlightening information would help!

[Otto Nobedder]

Adam,

Don't let anyone tell you you "must" walk the cup, or "must" freehand anything.

I do both, at my convenience. For me, I like to "walk" on 4" pipe and above, and "freehand" on anything smaller.

Ask twelve welders, you'll get 13 opinions.

Steve S

P.S. I've encountered road jobs that would specify "walk the cup"... so if you want the job...

[Mongol]

I also walk the cup at my convenience. Don't strictly rely on one or the other. And there are the occasional positions where walking the cup is damn near impossible. Why fight it? Just freehand.

I also wouldn't worry about back purging unless it's stainless steel or some other fancy alloy, but for open root you should clean both sides.

Running the root too cold will most likely give you lack of fusion/penetration. It can also cause a build up that makes it for difficult for the next pass to adequately fuse to the walls without grinding or filing.

Running it too will most likely result in root concavity, or "suck back"). Basically you're melting more metal than you're putting back. Adding an inadequate amount of filler can also cause this.

You also run the risk of having your puddle fall out on you resulting in an extra beefy root or having the puddle fall off the piece if overhead, or through the piece if on top. Not good if you're welding something that you can't easily access the inside.