Mig Welding Technique: Push or Pull the gun?

Once you have started to welding with a mig welder you going to ask which way do I move the gun. Should I move the gun left to right, or should I move it right to left when I am welding? And does it make any difference which mig welding technique I use.

The simple answer is yes, it does make a difference in both the weld bead profile shape and the depth of penetration. So to answer the question of should I push or pull the mig gun we need to take a look at some simple mig welding processes and once you can visualise how the welding bead and arc are being layed down, you will be able to make your own mind up as to which technique offers more welding penetration or if there is any difference at all.

Lets start off by saying that we are welding with the mig welding push technique. This is shown in the video below.

Mig welding push technique

Note:  The mig wire used in this video is 0.9mm which is 0.035".  In the text in the video I made a mistake and said it was 0.35" , I forgot to add the extra zero.

The theory behind the mig welding push technique is shown in the picture below.

To explain it as simply as possible would be for me to say that when you are pushing the mig gun, the arc will tend to be on top of the weld bead.  And also the very front leading edge of the weld puddle will be getting pushed infront of where you have to weld.  This is shown below.

Mig welding pull technique

This is a mig welding video shown the pull technique.  This way does actually offer deeper penetration when welding.

The reason why this method of mig welding has deeper penetration is beacuse the welding arc is not blocked by the weld puddle itself.  Therfore it can "bite" into the metal more.  See the picture below.

On thin sheet metal welding you may not notice much of a difference at all between the two.  But if you are doing some heavy plate welding using say a metal cored mig wire there will be a big difference.  The only way to tell for sure is to do some welding and then cut the metal apart to look at the cross sectional view to see the depth of penetration.

Return to the mig welding page.