Welding question

Ibayne

Well-Known Member
Joined
Jan 5, 2016
Location
Fletcher
So I’m no professional by any means, but I did have a failure. Part was the tubing I used just broke into. The weld I did stayed on the truck. But I also welded a gusset to this said piece an it seems like I just didn’t stick. My question is... What do you clean your metal with? Grinding wheel or Flap Disk? I use a flap disk always have, an I get the pieces looking like there polished. But I’ve also heard that if you get them to shiney the weld will bounce off.....opinions greatly appreciated
 
tknopp said:
What process did you use? Short circuit mig I assume. If so then it sounds like it was cold and didn't get enough penetration.
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or cold lap because short circuit, number one issue due to wire feeding the pool.....arc must stay in front.

As for weld "bouncing of shinny metal" no such thing, period. Welds don't bounce. Welds either penetrate or flow over adjacent areas. Do yourself a favor and recreate the joint and destructive test it or weld the same type of position and cut and etch with a torch.

It nothing was torn off the base material you weren't welding, just laying down liquid metal.
 
1106181602.jpg

Classic cold lap....on an otherwise fine looking weld. Absolutely good looking smooth weld, done wrong. Gmaw or Mig is the worst process for painting pretty turds on metal.
 
Ibayne said:
But I’ve also heard that if you get them to shiney the weld will bounce off.....opinions greatly appreciated
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WARRIORWELDING said:
It nothing was torn off the base material you weren't welding, just laying down liquid metal.
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Let's combine those two things. "...if you get them too shiny, when you lay down liquid metal it will bounce off".

If you're not-welding, polished surfaces will make your not-welding fall right off. :D

I'm a novice welder, but even I know something is really wrong if polished metal is affecting the weld quality.
 
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Post pics of breakage.
 
It’s was mig welded and looked exactly like this picture. Like you said one of the prettiest you’ve seen but failed miserably. What I don’t understand is how it failed. Makes me wonder about all the other ones now
WARRIORWELDING said:
View attachment 279391
Classic cold lap....on an otherwise fine looking weld. Absolutely good looking smooth weld, done wrong. Gmaw or Mig is the worst process for painting pretty turds on metal.
Click to expand...
 
Ibayne said:
It’s was mig welded and looked exactly like this picture. Like you said one of the prettiest you’ve seen but failed miserably. What I don’t understand is how it failed. Makes me wonder about all the other ones now
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Were you welding vertical or horizontal?
 
F4ECA14F-06C0-4F68-A6D3-745ABA8208FD.jpeg 548339DF-26A5-40CB-BB29-3FA2B3F99F5C.jpeg So add about 2 inches to what’s broke an that’s the part that snapped. But the second pic looks like the cold lap someone was discribing. It got hot enough to rainbow the tubing, just didn’t stick
 
Ibayne said:
It’s was mig welded and looked exactly like this picture. Like you said one of the prettiest you’ve seen but failed miserably. What I don’t understand is how it failed. Makes me wonder about all the other ones now
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going to slow or allowing the arc to ride the molten pool....that tiny little fireball is the only heat source where "work" gets done. Yes the related is also in a high temperature setting, but usually not enough for fusion. Short circuit mig has its draw backs.....limited to gauge material unless very specific procedures are followed....one being technique.

The other misinterpreted part of this process.....higher volts equals penetration.

Volts wets the pool. Amps make penetration. In this process amp is equal to wire speed feed. To little wire feed gives you a nice flat weld a lot of time with shallow penetration. It all has to balance. Some choose to run higher volts to slower wire speed. the result actually yields a shallow effective throat (less depth of fusion).
 
So, the gusset didn't fuse and the tube did. The tube tore away from the other member. The gusset did not appear to fuse. Therefor reinforcing nothing and theoretically allowed the whole mess to come apart.
 
WARRIORWELDING said:
This confuses me as well.
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Yes it had a notch in it. So it could kinda straddle the frame. The part that I welded to the frame stayed, can’t get it off without cutting. That break is past the notch. Like one has said the gusset didn’t do squat an my guess is it was to much for the tubing to bear and snapola
 
Short version for short circuit mig.

Too slow technique. Focus on keeping the arc on the front edge of the puddle. There is no “hold it there and let it burn in” with short circuit mig.

Definitely cold lap, meaning the puddle is insulating the arc from the base metal, causing lack of fusion on underside of the weld.
 
WARRIORWELDING said:
The other misinterpreted part of this process.....higher volts equals penetration.
Volts wets the pool. Amps make penetration. In this process amp is equal to wire speed feed. .
Click to expand...

But if you stop and think about their electrical relationship this makes perfect sense.
Volts and Amps have an inverse relationship. As voltage increases ampacity decreases for a given load.

Also higher voltage will jump a broader gap...in both circuit and welding application. So a higher volt setting will have a wider arc, because it "jumps further" and spread the energy over a wider area. Vs a lower votl setting will give a smaller more concentrated impact area, typically better penetration.

Welding has always fascinated me because of my love of electricity mainly.
I suck at it, though to be fair Ive never invested enough time to not suck at it. But unlike most who suck at welding. Im pretty good at sicking things together firmly. It just looks like absolute dog doo.

Before I got married and the only time I ever welded much in my life I was working on a couple projects with my future BIL and a mutual friend who was a welding inspector for industry process inspection.
He once told me that my welds were as structurally sound as most any he'd seen, but "they are so hideous no one would pay you for the work"...yet when I hear talented welders talk about the how and the why It makes no sense to my brain. Talk of moving the puddle etc...just isnt the way my mind works. Its like thinking in Chinese or something.
 
Ron said:
But if you stop and think about their electrical relationship this makes perfect sense.
Volts and Amps have an inverse relationship. As voltage increases ampacity decreases for a given load.

Also higher voltage will jump a broader gap...in both circuit and welding application. So a higher volt setting will have a wider arc, because it "jumps further" and spread the energy over a wider area. Vs a lower votl setting will give a smaller more concentrated impact area, typically better penetration.

Welding has always fascinated me because of my love of electricity mainly.
I suck at it, though to be fair Ive never invested enough time to not suck at it. But unlike most who suck at welding. Im pretty good at sicking things together firmly. It just looks like absolute dog doo.

Before I got married and the only time I ever welded much in my life I was working on a couple projects with my future BIL and a mutual friend who was a welding inspector for industry process inspection.
He once told me that my welds were as structurally sound as most any he'd seen, but "they are so hideous no one would pay you for the work"...yet when I hear talented welders talk about the how and the why It makes no sense to my brain. Talk of moving the puddle etc...just isnt the way my mind works. Its like thinking in Chinese or something.
Click to expand...
I also hit on this relationship....its exactly true in SMAW too! Though the machine maintains AMPERAGE the operator causes voltage fluctuations when he decreases or increases arc length. It is also why that process runs DC CC or constant current. I try to use words like inversely related but it goes over a lot of their heads. So I draw a balance beam and go from that. We also hit on the loss of Current over distance because of lead lengths and the feature built in some machines called DIG or Arc Force. It is the machines built in feature to ramp up or maintain certain Amps effected directly by arc length fluctuations or start up. The machine does this based on Voltage Fluctuations.

It is all relative. The REALLY sad part is most of the students refuse to try and digest this stuff and just want to make sparks at a given setting. At that point they aren't able to make adjustments to overcome poor fit ups, varying metal thickness and the related. I then have to fall back on what the operator is seeing. Your bead profile, spatter, and small tells to "read" the weld. Almost none retain the knowledge base that allows for educated weld setting or parameters based on presets applied to a given situation, IE starting point....It then becomes a knee jerk process of trail and error til they find the sweet spot. OR hey instructor what would you run this at? About 8 weeks into a 16 week semester I just roll my eyes and want to be somewhere else instead of babysitting people who refuse knowledge.

Wow, sorry about the rant.
 
Oh, and the topic of current density and the threshold where turning it up higher does no more work per diameter of electrode....mind blown!

"What do you mean we just can't keep tweaking it higher and higher for results?"

Transition settings usually are not a big deal you can see the results of the set points. But something like saturation of electrons is harder for them to wrap their heads around.
 
I always surface prep with a grinding wheel. It doesn't look like you even got all of the mill scale off of that pipe.
 
WARRIORWELDING said:
I also hit on this relationship....its exactly true in SMAW too! Though the machine maintains AMPERAGE the operator causes voltage fluctuations when he decreases or increases arc length. It is also why that process runs DC CC or constant current. I try to use words like inversely related but it goes over a lot of their heads. So I draw a balance beam and go from that. We also hit on the loss of Current over distance because of lead lengths and the feature built in some machines called DIG or Arc Force. It is the machines built in feature to ramp up or maintain certain Amps effected directly by arc length fluctuations or start up. The machine does this based on Voltage Fluctuations.

It is all relative. The REALLY sad part is most of the students refuse to try and digest this stuff and just want to make sparks at a given setting. At that point they aren't able to make adjustments to overcome poor fit ups, varying metal thickness and the related. I then have to fall back on what the operator is seeing. Your bead profile, spatter, and small tells to "read" the weld. Almost none retain the knowledge base that allows for educated weld setting or parameters based on presets applied to a given situation, IE starting point....It then becomes a knee jerk process of trail and error til they find the sweet spot. OR hey instructor what would you run this at? About 8 weeks into a 16 week semester I just roll my eyes and want to be somewhere else instead of babysitting people who refuse knowledge.

Wow, sorry about the rant.
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Wish I could like this more than once.

So many show up to weld bc they think to be good they won’t have to use their brain like in math, science, chemistry, machining etc.

once we start talking details of why and how, and how to read the weld, while welding in order to make a correction before a problem even occurs, most are dumbfounded while the good students soak it all in and run with it.

I wish I had better instructors like you when I was going thru. Unfortunately we had to learn it all the hard way, but the guys/girls that I was with around all discussed it and got there eventually.

One of the reasons we all get along and do well with it.

It did teach me what to do better when I started teaching, even though I was never planning to instruct.
 
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