Last Updated on September 29, 2020 by Gary Hargrave
Anyone who has interest in welding must have heard about MIG welding. As soon as thoughts about this particular process begin, the question, “MIG Welding Push or Pull” is sure to come up at some point. Both ‘push’ and ‘pull’ work and offer advantages over each other. Then, why is it a debate in the first place?
Pushing produces weld puddle that is smooth, flat, and wide. It is slightly more efficient in preventing cracking. Pulling ensures better penetration, narrower bead, and stronger weld. But you may lose sight of your direction, and the look of the weld may not be very appealing.
The answer may work for people who already know things about these techniques. But I believe more details will assist you in becoming knowledgeable and adept at the job. Let me start by explaining them one by one.
Topics Covered in This Article
- What Does It Mean to Push?
- What Does It Mean to Pull?
- The Most Desirable Welding Position: Flat Welding
- Another Common Position: Horizontal Position
- What Happens When You Exceed the Recommended Welding Angles?
- The Role of Your Workpiece
- Pushing for Thin Steel
- Pulling for Thick Steel and Both for Mild Steel
- Final Words
What Does It Mean to Push?
It is known as the forehand technique in which you push the MIG gun away from your weld puddle. I would say you’re going to push ahead of the puddle. In a way, all you do is push the gun toward the weld’s direction.
Apart from the many benefits of following this way, the best thing about pushing is that you can see right where you’re pushing the gun. It means you get the chance to see the joint. Many welding professionals push welds in an uphill direction just to see the condition of the joint and penetration into it.
It is much like you are able to keep your actions and results visible as you take them. You’ll see more than a few people support this particular technique only for the sake of visibility.
Pushing the gun allows you to create flatter, smoother, and much wider weld puddle which is sometimes a good thing as it covers a larger surface of your base metal. Again, the weld is expected to look aesthetically pleasing. A flat, smooth weld is one of the key reasons this technique is liked by professionals more often than never.
On the flip side, pushing is associated with lower penetration due to the force of the arc being directed far away from the puddle. You may have difficulty maintaining the strength of the weld, particularly in situations where the stress is higher than the usual. What can you make of this? You’ll be sacrificing the strength and keeping up the beauty.
What Does It Mean to Pull?
Don’t get confused to see the several names I’m going to give this one to. Call it the drag or pull technique. Even, it is correct to say it is a backhand or trailing technique. You point the MIG gun back at your weld puddle and drag it away carefully from the material that gets deposited.
So, you can see the exact point from which you’re dragging the gun from. Pulling a MIG gun is pretty much like the way you would go with a stick welding machine. After a pass is completed, it is likely for many people to be curious to get the view of the weld bead. If that population includes you, this is the method to follow.
Dragging or pulling is chosen by many welders as the default movement, and reasons for this tendency include the opportunity to know the size of the buildup or the need for adjusting any of the settings.
The deeper penetration you want, the more you’ll like pulling. That is what experts suggest. Not only dragging produces better penetration in the center, it also creates a narrower weld bead plus more buildup. Guess what happens. Deeper penetration into your base metal ensures a strong weld that holds pieces of the metal together.
The weld may get a little bit of a rounded shape losing its smoothness, and the look won’t be very attractive. To bring the standard and smooth feel of the weld, you may need to spend some time grinding it after the welding is done.
Am I creating confusion by not telling which one is the better of the two? Well, I would answer right away if the discussion was that straightforward. Now, I’m pointing out two popular welding positions where one technique beats the other. I hope you’ll be able to get real close to a well-informed decision.
The Most Desirable Welding Position: Flat Welding
Flat welding makes it easy for you to maintain comfortable positions over your weld as the workpiece sits level without any inclination to the point it’s going to be fused at. Gravity does the job of causing the weld pool to move as you need it, and you don’t need a lot of heat to ensure penetration.
How Pushing Works in Flat Welding?
The joint that lies ahead of the weld gets preheated, and the temperature of that section doesn’t change suddenly. As the weld reaches that section, you won’t see much of cracking. This is how pushing offers efficiency. But there again, you’ll get less penetration and a wider bead in the process.
How Pulling Works in Flat Welding?
In terms of the depth of penetration, this technique is clearly ahead. But you can barely assume the direction you’re moving. As the arc stays opposite to the surface that is not welded, the rest of the work piece won’t get as much preheated as it would with pushing. The bead will be relatively raised and narrow. So, you’ll get everything else except so much of penetration.
How to Choose Carefully to Avoid Losing Much?
Although the whole thing comes down to strength and aesthetics, you might not love to get only one of them to lose another. As long as you can maintain a specific welding angle, you don’t have to worry. Make sure you keep it within a 15° angle for any of the techniques.
Based on some experienced welders who have experienced great results this way, I can tell it is more than an unfounded theory. However, it is the location of the weld that determines which angle will be perfect for your particular project.
Another Common Position: Horizontal Position
Harder than a flat position, horizontal welding requires the gun to be pointed upward anywhere from 35° to 45° and tilted about 15° to 35° toward the weld’s direction. Do I need to mention which technique I’m talking about here? Pushing gives you an upper hand in this very position.
What Happens When You Exceed the Recommended Welding Angles?
Pushing produces less penetration along with a broader and flatter weld profile. Pulling provides deeper penetration with a more noticeable and taller bead. Practically, the result doesn’t change from what I discussed earlier.
The Role of Your Workpiece
If you need to produce basic beads on nothing fancier than flat steel, neither of the techniques matter much. Make sure the thickness of the metal is at least 0.25 inch and the wire stickout doesn’t exceed 0.75 inch. Note that the less the stickout is, the better it is for the shielding gas to do what it does.
Pushing for Thin Steel
The forehand/pushing technique allows you to make the travel faster and prevent much of the filler material from penetrating into your base metal. This penetration is known as fusion which is never good for thin steel if it occurs in excess. The more fusion your base metal gets, the more susceptible it becomes to have holes blown through it.
Pulling for Thick Steel and Both for Mild Steel
Maybe, you’ve understood this heading. But let me rephrase. The fusion and penetration produced by the pulling method are ideal for thick steel. However, you can rely on either way while working on mild steel.
Finally, you see that keeping one while crossing off another is not a viable course of action under all circumstances. So, I want to share a few more tips before finishing this article.
Don’t forget to feed the edge of your weld pool. I should say you have to concentrate on this. Avoid staying too close to the pool’s edge. Failing to turn far enough back to the pool while pulling or going too far away from it while pushing will result in small gaps absent filler materials.
When there are gaps in the pool, the weld becomes susceptible to compression, shear, torsion, tension, and other external forces only to be cracked or weakened. I am sure you don’t want any of these consequences.
At this point, I think I’ve provided adequate information about the topic. Feel free to tell me if you need to know something that I might have missed. Until then, I wish you great success in MIG welding.