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Please help me improve my MIG welds

martin_cho

Plastic
Joined
May 16, 2021
Learning how to MIG weld. I could use some feedback.

I've been practicing MIG welding in an effort to get better at it. Watched multiple videos online and spent a few hours consuming a full spool of 0.023 wire laying down beads in three dimensions (x, y and z), pulling, pushing and experimenting with different settings.

Equipment
Miller 130XP 120V welder, 75%/25% gas

Wire speed set to approximately 440 inches per minute (gas off, pulled the trigger for six seconds, measured wire, multiplied by ten). Voltage set to "4", which is the maximum setting. Those are the only two controls I have. I used recommendations I found online to choose wire speed.

Gas flow set to 25 CFH.

Wire
AWS A5.18 ER70S-6
0.023

The guy from Praxair recommended it. All I know about it is what I can Google. Not sure if this is the best option.

Material
1/8 nominal mild steel, brushed lightly with a stainless steel brush. While the material was clean, you can see what it looked like on the T assembly. Now I am thinking I should take a grinder to a few pieces and see how much different it might be.

Environment
Welding outdoors. A bit windy. I made a small shielded area with cinder blocks to try and keep wind from blowing off the shielding gas. This worked most of the time, yet, as can be seen in the images, whenever the wind got too strong I got popcorn. The effect was immediate. I tried to react and get the nozzle closer to the weld. Sometimes this worked, sometimes it did not.

The welder is rated at 90A 20% duty cycle. It is supposed to be able to make up to 130A. Right there I am thinking I was already operating at the limit for this machine. Not sure. In other words, I don't know if welding 1/8 steel with this machine is a plausible idea. I did take pauses for everything to cool down (machine and material).


PICTURE 1
zlt8TO3.png


Here I used all techniques I mentioned above, push, pull, x, y and z (clamped vertically) welding. The dots are intended to simulate tack welds.

The red circles are "wind events" that blew away the shielding gas.

Curious about the shinny spots, one of which is circled in green.

In general, please comment on anything you see and help me understand how to improve my welding. One of my challenges was keeping a steady hand. I was experimenting with different bracing techniques throughout. I was standing in front of my work surface, which was about waist high.

On the other side of this piece (which is about a foot long) I experimented with wire speed, voltage, stickout, gas flow, welding patterns (circles, "e", triangles, zig-zag, etc.) and welding travel speed. I built it up to a about a 1/4 of thickness before moving on. Not showing it. It's ugly.


PICTURE 2
RIIyM9A.png


OK, this was my "graduation" weld (one of two) after most of the spool was gone. Again, I am looking for critique and guidance on this. A friend told me the weld is cold. While this was glowing red hot as I welded, after some research I think this means I simply didn't have enough current and the weld bead needs to be flatter rather than convex (rounded out) as it is. This is what made me think I might need to get a larger machine due to the limitations of this one.

While I know this weld is likely structurally sound (I'll cut it today to look at penetration, etc.) I also know it could be improved. Just trying to figure out how.

All I did before taking this picture is take a few swipes with a stainless steel wire brush.

This is where you can see what the raw material looked like before welding. As I said above, I want to repeat some of this work after taking a grinder with a flapper disc to the surfaces.


PICTURE 3
P5yLDwH.png


On the other side of the same "graduation T" I attempted a bead on top of a bead. Not necessarily thrilled with the results. The wind was blowing a bit harder, so I got some popcorn in places. Also, the same issue with the bead being rounded rather than on the flatter side of things. Not sure how I fix that. Is it the machine, settings, technique?

On the next training run I'll consume a spool welding 0.060 nominal material, mostly tubing. As a "graduating" project, I'll probably try to make a cube out of 1x1 or 2x2 0.060 mild steel tubing and force myself to weld in all orientations. My gut feeling is that this machine should be able to do well with such a project and any issues will be down to my lack of experience and technique rather than anything else. I am very interested in learning if my suspicions regarding the use of this machine for 1/8 material are correct.


General notes/questions:

  • I don't mind buying a newer/larger machine. I have 220V available, so that would not be a problem.
  • What are the brown spots on the last picture? Is this bad? If so, how do I get rid of it other than grinding? In other words, is it a matter of technique?
  • PICTURE 2: How important is it to shoot for a "stack of dimes"? I was doing an "e" pattern on this one. Not sure how to achieve dimes.
  • Are the welds on the T structurally sound despite not looking professional? Is this something that can only be known through testing?
  • Can I/should I, weld this material without grinding it clean?
  • I was using 25 CFH for gas because it was a little windy. I can't weld indoors. Was that too much?
  • Is a newer inverter-based machine going to be easier for me? The 130 is about 20 years old, I think.
  • I learned that you need about 1A per thou. That means this machine can't really make it for 1/8 material. Right?
  • How flat should these welds be? They are rounded. My friend led me to believe the T welds were "cold" because they are rounded. Is he right?
  • Other than lots more practice (I got two more spools I want to burn through for learning), how else can I make my results more consistent?
  • How important is it to have a relaxed grip? I had to stop myself from clamping down too hard while welding.
  • What's the best working height? I was welding standing-up and the work surface was at waist level.
  • Should I try a larger diameter wire?
  • Is there a relationship between wire diameter and the thickness of the material you are welding? Is 0.023 too thin for what I am doing?
  • Should I be using a different type of wire (using ER70S-6)? How do I select it? Where do I learn about matching wire to material?
  • I there a different nozzle/setup that might make welding outdoors easier? I am thinking a welding blanket and three portable 6x8 ft shields.

I know that's a lot of questions. I probably have more. I am also hoping this might help other newbies in the future.

Thanks!
 

BT Fabrication

Hot Rolled
Joined
Nov 3, 2019
Learning how to MIG weld. I could use some feedback.


General notes/questions:

  • I don't mind buying a newer/larger machine. I have 220V available, so that would not be a problem.
    A bigger machine is always better, but it costs bigger $$. the 130A is a tiny machine and at best good for 1/8" max.
  • What are the brown spots on the last picture? Is this bad? If so, how do I get rid of it other than grinding? In other words, is it a matter of technique?
    the spots are the copper coating on the wire along with some of the cleaning silicon alloys added to get a stronger weld
  • PICTURE 2: How important is it to shoot for a "stack of dimes"? I was doing an "e" pattern on this one. Not sure how to achieve dimes.
    "dimes" are purely asthetic, penetration and root fill and even weld profile are better.
  • Are the welds on the T structurally sound despite not looking professional? Is this something that can only be known through testing?
    I would say too much wire speed and cold, so no, will most likely break if you hit it hard enough.
  • Can I/should I, weld this material without grinding it clean?
    with any welding, clean, clean, clean, and clean till its shiny.
  • I was using 25 CFH for gas because it was a little windy. I can't weld indoors. Was that too much? indoors is normally 15cfh, outdoors you would do better with flux core and reverse polarity.
  • Is a newer inverter-based machine going to be easier for me? The 130 is about 20 years old, I think.
    older transformers are better.....
  • I learned that you need about 1A per thou. That means this machine can't really make it for 1/8 material. Right? kinda sorta yes
  • How flat should these welds be? They are rounded. My friend led me to believe the T welds were "cold" because they are rounded. Is he right? yep!
  • Other than lots more practice (I got two more spools I want to burn through for learning), how else can I make my results more consistent? More hood time only.
  • How important is it to have a relaxed grip? I had to stop myself from clamping down too hard while welding. just be comfortable!
  • What's the best working height? I was welding standing-up and the work surface was at waist level. any height. ive been upside down many times.
  • Should I try a larger diameter wire? with that machine, maybe. 0.30 works best i found in thicker materials.
  • Is there a relationship between wire diameter and the thickness of the material you are welding? Is 0.023 too thin for what I am doing?you are fine.
  • Should I be using a different type of wire (using ER70S-6)? How do I select it? Where do I learn about matching wire to material? there are many, stick with what you have for now.
  • I there a different nozzle/setup that might make welding outdoors easier? I am thinking a welding blanket and three portable 6x8 ft shields.
flux core wire.

I know that's a lot of questions. I probably have more. I am also hoping this might help other newbies in the future.

Thanks!


replies above in questions.
 

dalmatiangirl61

Titanium
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
I'm no expert on small welders, but can say I struggle to get any good looking beads using them, they are ok when you need portable and doing light duty work. If you are committed to working outdoors get flux core .035 wire, and always grind before welding. If you want a larger/better machine look for an older transformer based welder, downside is they weigh a ton, upside is they will outlive you, and you can burn a mile of wire without stopping. My biased opinion is to find an old Lincoln Idealarc SP-200, make sure its the 220v single phase version, you will never want to use the cracker box again.
 

Rob F.

Diamond
Joined
Aug 5, 2012
Location
California, Central Coast
.023 is used for sheet metal and body shop work. the metal you are welding is a little thick to make a good weld. The porosity is from wind blowing away the gas. The brown deposits are I think silicon, they are normal. If you want to do the thicker metals 1/8" or more get some self shielding wire. It uses the opposite polarity so will be much better at getting the weld to penetrate into the base metal. My experience with little millers is that .035 is probably to big, it will work but the machine will be maxxed out to do it. .030 would be a much better size.
You will get a little spatter that should easily come off and the flux layer on the weld. Way stronger weld though.
Forget about the dimes until you get a tig machine, it is a mig weld, the ones you show look fine.
 

Homebrewblob

Stainless
Joined
Apr 5, 2020
Location
Cincinnati
Those welds look good! a little cold but good. i am no expert but I would want a tab bit more penetration, your doing great.

Just make sure you don’t penetrate too far and get undercutting.

If you near/at max amps then turn your wire feed speed down a tab.

If you outside then your shield is gonna blow away sometimes, just the nature of the beast.

If I weld outside I use flux core if possible.

Make sure you prep your metal before hand, flux core also really helps with dirty metal, back in the day when welding automotive exhaust I wouldn’t even prep the old rusty pipe, once the flux wire starts burning it’ll clean the metal ahead of you just fine.

If your doing real work (structural/pressure vessels) then you’ll need to perfect your technique and use gas shield. Practice practice practice
 

neilho

Titanium
Joined
Mar 23, 2006
Location
Vershire, Vermont
You're doing well, asking the right questions and getting good answers.

FWIW, my favorite bracing technique is right hand on the gun, gloved left hand supporting the torch just forward of right hand, elbow on something solid. On long straight welds, I pivot about the left elbow and rotate the gun with my hands to get a straight line.

Another way of detecting a cold weld is watching the shades of red along the margins while welding. Just after the puddle passes by, both the edge of the deposit and the base metal should be almost the same shade of red/white. If they're not, it's a cold weld.

There are ways to get more penetration out of a machine with marginal output. Turn the wire speed down, but not so far down that the wire sticks to the tip frequently. Less wire to melt = higher temps. Shorten the arc as much as possible. Weave faster, but don't advance faster.

Gun manipulation is key here, and practice helps.

On edit, I notice HB was quicker than I....
 

cyanidekid

Titanium
Joined
Jun 4, 2016
Location
Brooklyn NYC
where to start.. well, here goes...I'll say your getting off to a good start, asking a lot of the right questions, but no.. sorry.. those are terrible welds, just being real so don't be disheartened.

70S-6 is fine.

for welding with solid wire on hot rolled, especially as you learn, most certainly sand or grind off the mill scale.

sounds like your wire feed speed is too high, dial it down a bit.

yes, if you are serious get a better welder, that's a toy.

please, please, please forget about "stacking dimes"

for short circuit GMAW (MIG) , keep your wire contact at the leading edge of the puddle. slight leading angle.

torch manipulation. in a T joint, most important thing is to melt both legs of your T, so if you don't work side to side a bit, you can fail to get that tie in, but its really important to keep the wire in that leading edge of the puddle.

fluxcore is a different game, and its got a lot of different leagues. like self shielding "hobby" wire is like a kick-around sand lot match, and dual-shield .045-.062 is more like the premier league, the big time. don't even think about fluxcore unless you want to play in the bottom or the top of the game. vast majority of small scale fab GMAW is short circuit solid wire, or has been at least.
 

Rob F.

Diamond
Joined
Aug 5, 2012
Location
California, Central Coast
fluxcore is a different game, and its got a lot of different leagues. like self shielding "hobby" wire is like a kick-around sand lot match, and dual-shield .045-.062 is more like the premier league, the big time. don't even think about fluxcore unless you want to play in the bottom or the top of the game. vast majority of small scale fab GMAW is short circuit solid wire, or has been at least.

Dont even confuse him with dual shield, his machine could never even think of powering that. .045 would need about 200 amps. Esab makes an .035 dualshield , but still needs way more juice than the 110v machines can give.;)
HE needs esab core 15 as a first choice or lincoln nr211 as second. The esab core 15 will do all position, lincoln 211 I dont think will but there may be others that will. I use a lot of core 15, as well as core 8 and 7100 ultra, very little solid wire, unless stainless, but stainless dual shield sure does lay down with no crown:D
 

firststrike

Plastic
Joined
Jun 22, 2012
Location
wales, ystradgynlais
Hi, the welds you have produced are not looking particularly good. The reasons being that you don't seem to have someone guiding you on the correct techniques to use, it is very difficult to instruct someone without standing alongside them. I agree with a few of the comments above such as 1) the machine you are using is to small for what you're trying to produce. There are some very good inverter machines on the market for hobby user's that will give you in the region of 200 amps. The machine you have is probably good for auto shops.
You should always be "pushing" the wire as opposed to dragging it back toward you. Have a short gas shroud on the gun so that you have the contact tip exposed by at least a couple of mm this will reduce the arc length. Don't keep using a s/s brush on mild steel, in our shop those brushes would have to be binned.
Try to find a local fab shop that can spare a hour or two to point you in the right direction, you're more than welcome to come and spend a morning with us :D
Stick at it and things may get better but it is very difficult to self teach welding. p.s. the brown spots are silica.
 

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
Just looking at the bead shape you can see that there's not enough heat. I have a little Miller 135 and I only use it for sheet metal... I don't have a bigger wire machine at the moment so I use stick if I need to weld thicker stuff. Just FYI you can weld thicker stuff with that little machine if you preheat the work and/or premachine bevels on your plates. But it's a lot more work when simply changing to a bigger machine that can just burn it right in there is so easy.
 








 
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