[Mattman06]

I'm a novice tig welder. Im going to build a chromoly roll cage for my utv next month so I've been practicing with my notcher and welding tubes together. My welds don't look like they have enough filler compared to Jody's on his videos. I'm not sure if I need to move faster with more heat or what. I'm also not sure if 2 passes is a good idea. This is 1.75od .083 wall thickness 4130. Fupa#12 with 3/4" stickout. 100 amps. 26cfm argon. Thanks in advance. Matt

[Oscar]

Is there something preventing you from adding in more filler? What filler diameter are you using?

[Spartan]

First rule of fight club: Don’t clean your welds before taking pics if you want accurate advice and critiques of them.

Those welds look ok to me from the pics. I can tell you’re running hot, which is a good thing for chromoly. As long as you have good penetration throughout, there is nothing wrong with those welds. I’d guess you’re using .045 filler there. Try stepping up to 1/16” filler if you want a bit more buildup for aesthetics. If you’re already using 1/16 rod, then just meter in a bit more rod with each dab.

[Mattman06]

I'm using 1/16" er70s rod. 3/32 2% lanthanated tip. Its shiny until I get about 75 to 80% of the way around the tube then it starts to turn light grey. When I dab the rod should I feed in more than just touching the puddle?

[Spartan]

I'm using 1/16" er70s rod. 3/32 2% lanthanated tip. Its shiny until I get about 75 to 80% of the way around the tube then it starts to turn light grey. When I dab the rod should I feed in more than just touching the puddle?

Yup, just push a bit more rod in with each dab.

And there's nothing wrong with grey welds on chromoly. To be honest, I prefer grey over shiny for that material. There's little room for instagram pics when it comes to making good/strong welds on chromoly.

[Louie1961]

There is nothing wrong with two passes. Jody does that in a couple of his tubing welding videos

[bap_]

I was just going to mention the same thing. I a lot of folks doing 1.75 and 2inch .125 wall do a root and cap pass. First pass is to get good root penetration, second pass it for reinforcement and aesthetic.

Also cut and etch on your practice pieces could be a great learning experience or maybe a good old fashion hammering.

[Mattman06]

Thanks. I'll cut some more pipe and try again tonight. Jody makes this stuff look so damn easy lol.

[cj737]

1/16 wire for 0.083 is not the right wire to be “technically correct” where a roll cage is concerned. If this is just for looks in your UTV, fine, but if it might actually be called upon to save your neck, two passes or 1 with 3/32 and make dead certain you’re getting full penetration. I’d even step up the amps and jam more filler driving the filler in deeper.

A bevel on the tube edge is also a great choice. You can use a flap disk to grind it. And lastly, when you do the final tubing, clean the inside of the tube really well for at least 2” away from the joint. Your welds will be that much better.

But your welds look very good for your stated experience level.

[Spartan]

Keep in mind also that your heat control will be just a bit easier when you are welding on longer lengths of tube for the actual job. Those test pieces have you artificially welding somewhat close to edges and there the heat will buildup with no place else to go.

And if we all tried to make all of our welds look like Jody's, we'd be in for a hard, sad time

[Louie1961]

Have you seen Jody's latest video? Its all about Chrome Moly tubing. He preferred to do two passes with smaller diameter wire. He uses 0.045 wire for tacking and he uses 0.045 and 1/16th filler for the first pass. He uses 1/16th rod exclusively for the second pass. I personally would NOT use 3/32 filler since it is thicker than the base metal you are welding (.094 rod vs .083 wall thickness) and that is never a good answer, for TIG or Stick welding. if you use 3/32 rod you will either have a hard time not burning through, or you will just chill the puddle too much.


https://www.youtube.com/watch?v=WoIgZxm9k8U&t=449s

[Mattman06]

Tried adding more rod.

[Mattman06]

Is this good penetration?

[Poland308]

Looks like there was no back purge. The sugaring is why your cover pass has so much grey. It’s pulling contaminants through the weld puddle to the top. Being that your practicing for roll cage that could be a problem. Those particles are just as likely in the middle of your weld. I’d recommend doing a cross cut and etch to see if your getting good penetration.

[Mattman06]

I'm not set up for back purging yet. I'll see if I can get another tank and regulator next week. I turned the amperage down to 85 on this one. Did it in 4 sections. Opposite sides then let it cool for a few minutes the did the other 2 sections.

[Poland308]

https://www.amazon.com/AIC-WELD-Regulat ... 4602&psc=1

For a lot less money you can just use a regulator like this.

[Spartan]

Don't overthink it. We used to call that "nuking it out" in the navy. You're doing all the right things for good welds on chromoly. Go beat those test pieces with a sledge hammer and you'll see that those welds will be the last thing to fail. The pieces will actually be completely unrecognizable long before you will get one of those welds to break.

[Mattman06]

Not sure if this helps but I cut the welds from the first post.

[Mattman06]

Don't overthink it. We used to call that "nuking it out" in the navy. You're doing all the right things for good welds on chromoly. Go beat those test pieces with a sledge hammer and you'll see that those welds will be the last thing to fail. The pieces will actually be completely unrecognizable long before you will get one of those welds to break.

Awesome. I was thinking of putting it in the press and seeing what happens.

[cj737]

In general, purging chore moly is not required, but it is a great recommendation. However, you still need to clean the areas near the welds on the inside to eliminate contamination.

Your welds show some better penetration, but not full penetration completely around the weld. That is/is not a problem depending upon several factors. Bottom picture, left side, there's a gap at the seam where you did not get weld into the root. This is why beveling helps even on 0.083 wall tubing.

The advantage of a single pass with 3/32 wire (some may disagree) is that you can get full penetration AND enough root plus welded toes to improve the strength of the weld completely. 1/16 filler can get you full penetration, but you will not have enough wire left over to create a fillet for added strength. And, as you did, you will create undercut with thinner wire.

But, if you are going to use 3/32 in a single pass, you must get fully penetrated or you will (as someone pointed out) not actually improve the strength of the weld, but simply be too cold. Welding tubing is challenging. Reposition constantly. CroMo does not like to be overheated so adding filler to chill the puddle is important with higher amps.

[Mattman06]

So I should bevel the edge so theres a small gap at the outside of the wall but the inside has no gap? That's so the filler goes all the way to the inside edge of the wall correct? I'm going to run by airgas on a test drive and get some 3/32 wire. Try a few runs and post them up. Thanks to everyone who is taking time out of their days to help. Matt

[Louie1961]

The advantage of a single pass with 3/32 wire (some may disagree) is that you can get full penetration AND enough root plus welded toes to improve the strength of the weld completely. 1/16 filler can get you full penetration, but you will not have enough wire left over to create a fillet for added strength. And, as you did, you will create undercut with thinner wire.

Some may disagree? I guess Jody disagrees with you too. He has at least a half dozen videos on welding chrome moly tubing and in every one he is using 0.045 wire or 1/16th wire. He even has published advice on how to select filler wire. Your advice is completely opposite of his. No offense, but I am taking his advice over yours every time.

https://www.weldingtipsandtricks.com/ti ... -size.html

[Louie1961]

Not sure if this helps but I cut the welds from the first post.

I would love to see you polish and etch those weld beads and post close up shots of just the beads. I cant really tell from the pictures how good or bad your welds actually are. From a distance they don't look bad, but the closeups will tell more

[cj737]

Some may disagree? I guess Jody disagrees with you too. He has at least a half dozen videos on welding chrome moly tubing and in every one he is using 0.045 wire or 1/16th wire. He even has published advice on how to select filler wire. Your advice is completely opposite of his. No offense, but I am taking his advice over yours every time.

Well, to quote Jody in that video within the first 20", "There is NO definitive answer on what size wire as it all depends upon the application.". Guess you missed that part.

"Rule of thumb" is just that, a general guide. It does Not dictate what you must, or should not do. It is a basis for making a decision. If you read carefully exactly what I wrote, you might understand the specific conditions for which I would choose a single pass with a 3/32 wire. I have never said 2 passes would not be a good choice too. I only said, "full penetration, single pass, up the amps".

The very real case for undercut with smaller wire outweighs the risk of using a larger wire at higher amps in many people's book. And to be honest, 0.083 wall tubing isn't really "roll cage material" in any sanctioned sport. Minimum that I have ever seen is 0.120. I have much respect for Jody and his vast experience, but I am fairly certain in nearly EVERY video he will openly admit he is NOT the end-all, be-all on welding. There are numerous folks who do this for a living, and some of these good people I know and base my recommendation on their counsel. Because their frames pass RACE SPEC every time.

I suspect that if the OP welded up 4-6 sample pieces, cut and etch them fully, he would find numerous points of lack of fusion/penetration because he was trying to control the heat (using lower amps based upon wire diameter) and even a cover pass would not provide the strength necessary for a roll cage to survive a catastrophic crash. And if he did get full penetration with 0.045 or 0.063 on 0.083, dollar to a donut he has undercut all along that weld. Do you know anyone who would feel that is okay? Bet "Jody" would discard that tube in 1 second flat.

So Louie, you are free to choose for you. I am merely offering the OP another option to consider.

[Louie1961]

I sure would love to see some pics off those welds made with 3/32 rod that passed race specs.