Pulsed GMAW on 1/4" carbon steel with 75/25 gas?

[RenoHuskerDu]

I'm new to pulsed but not to GMAW. Had to sell my entire welding rig when we escaped yurrup, wrong volts/hertz. Just bought a Multimatic 255 and a bottle of 75/25. Now I'm reading (here) that I need more argon in the mix to do pulsed. I ordered a bottle of 90/10 but it won't be here for a week.

Meanwhile, I need to weld up sagging airbag perches on a truck frame. It's all heavy steel. Would 75/25 be OK for that? Should I not pulse that job? I was planning to let the Multimatic automatically configure volts, pulse, IPM. Never had such a nice welder before, it's a treat.

I watched a few of Miller's videos on advantages of pulse so figured I'd pulse most everything from now on. Maybe that's wrong....

Thanks guys

 

[Gary Fowler]

MIG worked for many years welding all kinds of things before pulse control was invented, so I would say that you would be ok to weld anything you wanted without the pulse setting.

When pulse first came out they touted that it was great for reducing lack of fusion at the sides. You were supposed to time your weaves side to side so that the high amp pulse was on each side and the low amp was when you crossed the middle of the weld puddle. I haven't welded with any of the new pulse rigs but from what I see, they look to do pulses rapidly now.

 

[RenoHuskerDu]

MIG worked for many years welding all kinds of things before pulse control was invented, so I would say that you would be ok to weld anything you wanted without the pulse setting.

When pulse first came out they touted that it was great for reducing lack of fusion at the sides. You were supposed to time your weaves side to side so that the high amp pulse was on each side and the low amp was when you crossed the middle of the weld puddle. I haven't welded with any of the new pulse rigs but from what I see, they look to do pulses rapidly now.

Oh yeah, the pulses are many times per second. Can't move the arc that fast. Thanks for the advice. I cleaned up the metal last night and devised a triangulation weld using stock that should be stronger and will be easier to get the gun in there. Pics to follow.

 

[CB]

I now regret that you had to go to the Miller forum to get your question answered, because I saw your question the day you posted it here (first), and then got busy and didn't answer. The entire idea of THIS forum is so that folks don't have to go to a manufacturer specific forum. But then again, you did just buy a Miller, so can't say I blame you. But you're in on the ground floor of THIS forum!

I didn't answer right away, because I felt that it might take longer to answer than I had time for at that moment, and I didn't want to discourage you from your excitement in trying pulse for everything.

I think your question is a bit more complicated than meets the eye, because of continuous improvement in waveforms, and because recent inverter technology (or rather, the economically scaled lower cost, and resulting higher availability of the same) enables higher frequency switching that wasn't possible in pulse machines of the previous 2 decades.

But more specific to your project... welding air bag perches on the web of a truck frame, which sounds like a vertical uphill run on .250" plate... you not only don't need pulse, you might not want pulse until you have more experience with it. Short circuit will let you control the travel speed up hill, and give you time to trace the leading edge of the puddle from the frame to the air bag hanger and back again.

And then the question came to mind... why are you welding the air bag perches to the frame? Why not bolt them? Then you don't have to worry about a HAZ between the leaf spring hangers.

 

[RenoHuskerDu]

I now regret that you had to go to the Miller forum to get your question answered, because I saw your question the day you posted it here (first), and then got busy and didn't answer. The entire idea of THIS forum is so that folks don't have to go to a manufacturer specific forum. But then again, you did just buy a Miller, so can't say I blame you. But you're in on the ground floor of THIS forum!

I didn't answer right away, because I felt that it might take longer to answer than I had time for at that moment, and I didn't want to discourage you from your excitement in trying pulse for everything.

I think your question is a bit more complicated than meets the eye, because of continuous improvement in waveforms, and because recent inverter technology (or rather, the economically scaled lower cost, and resulting higher availability of the same) enables higher frequency switching that wasn't possible in pulse machines of the previous 2 decades.

But more specific to your project... welding air bag perches on the web of a truck frame, which sounds like a vertical uphill run on .250" plate... you not only don't need pulse, you might not want pulse until you have more experience with it. Short circuit will let you control the travel speed up hill, and give you time to trace the leading edge of the puddle from the frame to the air bag hanger and back again.

And then the question came to mind... why are you welding the air bag perches to the frame? Why not bolt them? Then you don't have to worry about a HAZ between the leaf spring hangers.

Sorry to reply so late. I don't know how I missed your post. I wound up using GMAW with the 255's Auto-Set feature and 75/25 gas. And I switched plans to adding a horizontal triangulation up high where they had bent, instead of simply welding the perches on (they are also bolted to the frame rails) . I understand basic geometry and angles of force, so this seemed not only wiser but easier. Added plus is that if I ever need to remove the perches, this brace is easy to access with a cutter or torch. See the result below.


The Multimatic 255 Auto-Set has to be tried to believe. Every time so far, it's flawless and I don't have to adjust a thing. It sets IPM and voltage, then varies both while I'm running the bead, and I have no idea how it's doing that, but it works. I did have one problem bead but it was because I got lazy and didn't properly clean a rusty old catalyst shell I was welding onto a 4" 16ga exhaust pipe. Spatter. So I stopped and broke out the wire brush, which made the welding easy again. Pic attached before I cleaned it up. I get into a 6011 rod mode out here on the ranch of welding up anything even with old paint on it. I have to stop myself and say "no this is a nice welder and nice job, stop being a wild man."

 

[RenoHuskerDu]

BTW, still waiting on a bottle of 90/10 gas, ordered it two weeks ago now. Nobody around here has a 150 in stock, which is the size I want so I can fit 3 bottles on my cart. Seems odd, I wonder if the Chinese virus will be the excuse for poor gas inventory management, or whatever. This is Texas and every rancher welds.

 

[Gary Fowler]

BTW, still waiting on a bottle of 90/10 gas, ordered it two weeks ago now. Nobody around here has a 150 in stock, which is the size I want so I can fit 3 bottles on my cart. Seems odd, I wonder if the Chinese virus will be the excuse for poor gas inventory management, or whatever. This is Texas and every rancher welds.

Just curious, how much did you have to pay for a 150 CF bottle. My 125 CF was $300 plus tax. IIRC the 80 CF bottle were not much cheaper like $270 or thereabout. I didnt price anything larger because the 100 CF is about all I want to be wrestling around. BTW, my LWS calls the 125 a 100 when filling it. I did

 

[RenoHuskerDu]

Just curious, how much did you have to pay for a 150 CF bottle. My 125 CF was $300 plus tax. IIRC the 80 CF bottle were not much cheaper like $270 or thereabout. I didnt price anything larger because the 100 CF is about all I want to be wrestling around. BTW, my LWS calls the 125 a 100 when filling it. I did

The 150 of 75/25 was about $350. Whenever I get my 90/10 I'll let you know....

 

[Yomax4]

BTW, still waiting on a bottle of 90/10 gas, ordered it two weeks ago now. Nobody around here has a 150 in stock, which is the size I want so I can fit 3 bottles on my cart. Seems odd, I wonder if the Chinese virus will be the excuse for poor gas inventory management, or whatever. This is Texas and every rancher welds.

Na not the virus. I don't know any LWS that pumps 90/10 into 150's. I'm SHOCKED at the price for the tank and gas. WTH?. I need to count my blessings. Ooof Dah.

 

[Yomax4]

Sorry to reply so late. I don't know how I missed your post. I wound up using GMAW with the 255's Auto-Set feature and 75/25 gas. And I switched plans to adding a horizontal triangulation up high where they had bent, instead of simply welding the perches on (they are also bolted to the frame rails) . I understand basic geometry and angles of force, so this seemed not only wiser but easier. Added plus is that if I ever need to remove the perches, this brace is easy to access with a cutter or torch. See the result below.
View attachment 1134

The Multimatic 255 Auto-Set has to be tried to believe. Every time so far, it's flawless and I don't have to adjust a thing. It sets IPM and voltage, then varies both while I'm running the bead, and I have no idea how it's doing that, but it works. I did have one problem bead but it was because I got lazy and didn't properly clean a rusty old catalyst shell I was welding onto a 4" 16ga exhaust pipe. Spatter. So I stopped and broke out the wire brush, which made the welding easy again. Pic attached before I cleaned it up. I get into a 6011 rod mode out here on the ranch of welding up anything even with old paint on it. I have to stop myself and say "no this is a nice welder and nice job, stop being a wild man."
View attachment 1135

Enjoy the Pulsed Mig. It's a great feature. Just wait til you move up to the next level where you can adjust pulses per second and control the heat and duration of each pulse with Twin Pulse which easily replaces short arc.