“MIG Welding Techniques”
In this article I’m going to go over:
- MIG welding techniques
- MIG welder fine tuning
- Weld speed and hand position
- MIG weld bead spacing
- Types of joints, how to weld them, and much more…
When I first started learning how to weld I had no idea where to go to get information for the proper techniques of how to make a nice looking and strong MIG-weld bead.
ie: MIG-welding like stack-of-dimes or like a TIG-weld, etc.
I’ve learned a lot from my many years in the off-road fabrication industry. In this article I’m going to try and save you time by sharing my experiences in welding and fabrication and hopefully I can educate you with my many tips and techniques to steer you in the right direction to having that “Perfect MIG Bead.’‘
There are definitely many different techniques to get that “stack-of-dimes” or “Mig like Tig” look but before we get started we have a couple things we should go over;
First, you’re going to have to adjust the settings on your welder. I would use the Chart on the inside of the door as a good starting point. On some welders you will be able to use these settings while others may require further tuning. In the two pictures below I’ve used the stock Miller settings. Once you have the welder set for the material you are welding here are some of the tricks to start getting the “stack of dimes”:
- Start by dropping your wire speed.
- If that doesn’t help, drop the settings down to the next lowest setting on the panel.
- If still nothing, you’ll have to continue fine tuning by dropping your wire speed. Then your volt settings. Repeat that process until you have a nice consistent sharp “Frying Bacon” sound along with a nice rounded bead stack.
- Drag the welder close to the area you’re welding – enough so that you can reach over and touch the adjustment knobs while welding.
- Get the welder’s settings close to your liking.
- Then, while welding on a piece of scrap, slowly turn the wire speed knob up or down until you get your sharp “Frying Bacon” sound along with a nice looking bead.
I mentioned that I was using the stock Miller 250 settings, which work well in certain applications but may need to be adjusted depending on the part you’re welding. In the picture below I was using the stock Miller settings for 3/16″ to show you what it looks like when you try to weld a corner joint. I’ve tried to make the weld look as decent as possible but ended up using the stock Miller setting for 16 gauge.
In my experience, each welder has different settings to get that “Sweet Spot”. For example, I use a Miller 210 all the time and have the settings memorized but at my friend’s shop I use completely different settings on his identical welder. I’m not quite sure why the settings can vary so much but if you use the techniques I’ve explained above you should be able to tune any welder to get the best welds possible.
If you change to a different wire size you will have to change the settings to get back to your desired “Sweet Spot”.
One way to inspect the penetration of your weld, without an X-ray or cross-section, is by the way the bead looks.
- If the weld is very tall, rough, or choppy, then the penetration may be insufficient. This is referred to as being TOO COLD!!
- If the weld is close to flat or slightly rounded, this is an indication that you’re getting the penetration you want. I’ve shown an example of a 3/16″ T- joint & lap joint in the pictures above.
- You don’t want the weld to be “Under Cut” which means below flat or cutting out the material.
Another way to insure that you have good penetration is:
- A large chamfer on the material.
- An equal reveal on the material.
- A higher setting on the welder — especially for thicker material.
- A slower place — allowing more heat and more weld material to the joint — and a bigger “C”or “e” formation.
The Welding Technique
- I don’t stitch weld because you usually don’t get the penetration you want — unless I’m using a thinner material and wire such as sheet metal welding.
- I don’t push from right to left because it’s harder to get penetration. For that reason the weld is being pushed away from the molten puddle unlike the pulling technique where your wire is pushing back into the molten puddle. Also, the weld is a lot harder to control to make the weld look appealing.
The main welding technique I use is fairly different from other techniques like “C” or “e”. Even though I do use the “E” in some situations The technique I use is a back and forth motion all the while pulling left to right — if your left-handed, the opposite applies — with the nozzle of the gun at a 45 degree angle. I aim the wire in the center of the joint where the two metals meet.
If there is a thicker piece of metal on one side, I will use an “e” formation. I will push the weld in an “e” formation towards the thicker piece. If there is a gap or divot that needs to be filled, I will slow down and do the “e” formation to completely fill the gap or divot.
Tip: I prefer to use a smaller gun than the one supplied for more control and the ability to weld in tight areas.
Hand Speed and Hand Position
Let’s start with the Hand position:
- Hold the trigger part of the gun in your right hand with the ability to rotate your wrist – like the throttle on a motorcycle handle.
- You will want to rest the bend of the gun in between your pointer finger and the thumb with the top of your hand resting on the table.
- Your left hand is going to be the point for the gun to pivot on and to stabilize the nozzle.
- Your right hand is going to be the part that twists to achieve the back-and-forth motion that creates your weld beads.
- Also, you’re going to want to relax your arms and hands so you can slide your left hand across the table to follow the weld down the joint.
When I was first starting out I would weld like I was in a hurry. Don’t rush!.. Take your time. You need to relax your grip — the gun isn’t going anywhere.
- When you start the weld, relax!! Do a nice little loop to close off the end of the material.
- Start by pulling to the right about a 1/8″ to 1/4″ or less in a semi-fast motion.
- Push the puddle back over what weld I’ve just laid down at a slower speed and watch the bead form a nice round puddle.
- When I push back, I watch the spacing of the bead in front and try to match the stopping point of the puddle that I did from the previous puddle. That’s how I know how far I need to push back the puddle.
MIG Weld Bead Spacing
When you space your weld beads you will want to have them equally spaced and close enough so as not to get a “Scalloped” formation. If you’re getting a “Scalloped” formation it’s probably because you’re going too fast and you’re not pushing left far enough to cover the weld that you just made. Also, you may be pulling away from bead — to the right — too far.
Make Sure You Can See!
When I first started, I also had a problem seeing the weld. Now I’m not sure if it was a mental thing of not getting my face close enough to the weld or if the lens on my hood wasn’t clean. It could have been a combination of both but, eventually, I was able to see and have figured out what can help you to improve your visibility which, in turn, will improve your welds, dramatically.
Tip: Make sure your clear lenses are as clean as possible. Remember, you get one shot at your weld.
- The first thing you want to do is make sure that the shade of your hood is set up for you.
- I use a shade 11-1/2 or 12 on my auto darkening hood. If you are just starting out, I would try a shade 9 or 10. Then increase to a darker shade when you get all the techniques down pat and you’re comfortable.
- Another very important step in your visibility is cleaning the lenses on your hood. Sometimes the lens may not look very dirty but you would be surprised how hard it is to see if you have a dirty hood lens compared to a new one.
- What I use and have found to work better than anything else I’ve used to clean the lens (WD-40, wet rag, soap and water etc) is a plastic Polish. It’s called NOVUS POLISH #2 Fine Scratch Polish, which restores the lens close to the original finish giving you that new lens visibility.
- I would apply this every 10-20 welds depending on how much you weld.
- Lastly, make sure you’re getting close enough to the weld. When I weld I’ll put my face between 5”-12” away from the weld — 5” being the closest and 12” being the farthest – and, no, I don’t wear glasses.
- Now, you’re probably thinking, “Man I’m going to have major back and neck problems after welding being so bent over.” Well, one thing that you can do is raise your table or raise the part so you don’t have to bend down so far. This will eliminate chiropractor bills.
MIG Nozzle and Anti Splatter
It’s very important to keep the nozzle of your gun clean while your MIG welding. If you don’t sometimes the splatter buildup in the nozzle will break off and get stuck in your weld. Also, when I weld I use the nozzle as a guide by dragging it in between the two pieces of steel, and if the nozzle has buildup it will fuse to the material and stop the gun in its tracks.
So, to prevent this from happening I use an Anti Spatter spray and small pliers to break out the spatter slag from the nozzle. I try to clean the nozzle every other weld to prevent these events from happening.
When you’re prepping your material before you weld, there are a few things you want to take into consideration. The better you prep your joint, and clean any unnecessary contaminates — paint, mill scale, rust, frame wax, powder coat etc. — the better the weld will turn out.
It’s important to remove contaminates so you don’t get “Weld Porosity” while welding — “Moon Craters”. In turn this creates stress risers and a place to crack or separate.
Porosity — “Gas entrapped in solidifying metal forms spherical pores in the weld, known as Porosity or “Moon Craters.“ Porosity in the weld and heat affected zone may lead to “Cracking.”
Here are the leading reasons for porosity.
- Improperly controlled welding process.
- Contamination on the base metal such as oil or paint.
- Insufficient shielding gas flow.
- Welding in windy conditions.
The Fitment is also very important. Without the right reveal on the joint or chamfer, you could be compromising the strength of the part by not getting an adequate amount of weld penetration through the joint leaving the welds not as consistent. It is crucial to take your time to make the fitment as consistent as possible.
- After all contaminates are ground off or removed with a wire wheel, grinder etc., wipe the parts clean with Acetone. Now you can set up your weld joints — some differently than others depending on the thickness of material or type of joint.
- For a corner joint — let’s say 1/8” plate” – you’re going to want the thickness of the material evenly spaced on both sides throughout the joint. Sometimes I’ll even sneak in a 1/32″ or so gap in between the joint to make sure I get a good penetration all the way through the joint and a better looking weld.
- For a T-joint fillet weld– say on 1/4″ or 3/8″ plate — I’ll grind a nice chamfer on the side I’m welding. While that’s not a 100% necessary for every joint, you’re going to have to be the judge as to what the part is for and how much penetration is needed. Here’s an example of a good way to fill this type of gap.
Types of joints
The corner joint can be one of the easiest or hardest joint to weld for a couple different reasons.
- If you’re welding 3/16″ and up it get easier the thicker you get.
- It helps in knowing when to pull back.
- It gives you a joint to fill with weld unlike a t joint.
- If its 1/8″ or less corner joint it’s extremely hard to weld.
Heres an example on how to weld a Corner joint:
- When you’re welding 3/16″ and thicker plates together it’s easy to fill because of the larger joint area and depth and will allow you to move much slower while welding.
- It helps in knowing when to pull back because when you weld a corner joint you use the push pull technique (above) and while you push the weld to the left to create the rounded bead you break the top edges of the joint and that’s your indicator that you need to pull back to the right. ”So, fill up the joint until the weld breaks the edges and pull back then repeat.”
- It gives you that big v joint to fill up which gives you a guide on how much weld to lay down until you need to move.
- A 1/8″ corner joint is an extremely hard joint to weld because of the lack of joint to fill and therefore the welding speed is dramatically increased.
Fillet or Lap Joint
Butt Joint and Slot Weld
Circular Fillet and Corner Welds
How to fill a gap
I’m still working on adding new content every week, so check back periodically for more welding tips & techniques… oh, and leave a comment if you have any questions or would like me to add anything related to Mig-Welding, I’ll be happy to put it to the article.
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