Introduction: Proper Metal Insert Gas (MIG) Welding Technique

Metal Insert Gas (MIG) welding is a skill that is utilized by many people in industrial fields.  Nowadays it's proper name is Gas Metal Arc Welding (GMAW) but it is still referred to as MIG welding.  Compared to various types of welding, MIG is one of the easier techniques to learn.  With a little practice anyone is capable of being able to do it.

MIG welding is a process that has an electric arc form between the wire electrodes and causes the two metal work pieces to melt and join together.  Now the gas comes into play because a shielding gas feeds through the welding gun which protects from contaminants in the air.  Since its creation in the 1940's, the concepts have stayed the same as with the technique used for it.  Now this Instructable is meant to be a guide on the proper technique of MIG welding.  If you are looking for a general process you may want to seek out a more comprehensive guide on MIG welding as a whole.

Step 1: Materials Needed

• Safety Equipment
     o Welding mask
     o Flameproof jacket
     o Heat resistant gloves
     o Closed toed shoes
     o Jeans or other cotton made pants
     o Fire extinguisher
• The Welder
• Gas Tank
• Welding Gun
• Ground Clamp

All of the safety equipment is there to ensure you do not get hurt during this process.  There are a lot of sparks and extremely hot metal created from this process which can in turn start fires.  By having a fire extinguisher nearby and flame resistant clothing, you can prevent this from happening.

Step 2: Helpful Tips

A few helpful tips you may want before you become a professional welder.  First off, know your welder.  All welders do the same work but not all of them have the same settings or necessities as another.  By working with an expert you can learn exactly how to change out the wire, apply the gas, or even change the different electrode settings.  Knowing the different parts of the machine can limit the mistakes made during the welding process.

Lastly, practice makes perfect.  Before welding two pieces of metal together you will want to practice laying a bead with the welding gun.  This can be done on any piece of scrap metal.  MIG welding has a certain touch to it that you can only perfect by practicing.  Once you feel confident with laying a bead on scrap metal, feel free to try welding two pieces of metal together.  Just know they have to be the same type of metal otherwise they will not bond together.  After practicing your technique, you should be confident enough to weld any piece of metal all on your own.

Step 3: Prepare the Metal

Now you may think that all you have to do is to take the welding gun, squeeze the trigger, and touch it to your work piece to lay a bead.  Unfortunately there is more to it than that.  To ensure your weld is successful you will want to take a close look at your pieces of metal and ensure they are ready to be welded on.  All pieces of metal need to be clean of rust or paint and if not done so, contaminants will find their way into the weld and reduce it’s strength.  Not only that but it will be difficult to push the wire to create an arc against a dirty surface. 

Some metals may be easy enough to clean with just a wire brush.  More serious cases may call for a sander or angle grinder to scrub off any rust or paint.  By applying these to your weld area beforehand, you will save yourself time, money, and the possibility of a failed weld.

Step 4: Holding the Welding Gun

Because the MIG torch, or gun, can be easily gripped and operated, it can be used with one hand.  But MIG welding is much easier and more accurate if you use two hands.  The whole purpose of this is to have one hand operate the gun while the other steady and angle the torch properly.  Only use one hand can cause the tip to jump around and create a weak bond. 

To operate the gun all you have to do is squeeze the trigger and touch the wire tip to the metal to create an electric current that heat up the pieces to create a bond.  Once you become accustom gripping the torch, you can bring in your other hand to support the neck of the torch to create a straight accurate bead.  In the picture you will see the left hand will rest on the table surface and act as a pivoting tool for the other hand to lay a bead on the surface.

Step 5: Position the Wire Tip

Before you touch the wire tip to the metal, you want to ensure it is extruding from the welding torch by approximately 6mm to 10mm.  If you squeeze the trigger without having the tip touching any metal, the wire will feed through the torch and at which point you will need to cut the wire so the tip is back to its necessary length.  After you become comfortable with the wire speed you will want to learn the proper position to hold the torch at. 

Since MIG welding allows you to weld many different objects at various angles, there is no proper way to position the tip.  Holding the torch at a 20 degree angle is ideal for flat surfaces.  When it comes to welding two pieces at a corner, you will want to hold the torch at a 45 degree angle so it can create an even bond between each piece.  These are all ideal techniques; once you get enough practice at welding you can get a feel for what works best for you.  As said earlier, there is no correct for to MIG welding just ideal situations.

Step 6: Push Vs Pull

Whether you push or pull the torch, it does not make a big difference between the weld qualities.  Although pushing the torch is a better habit to have as it improves the coverage of the shielding gas.  If you are looking for a more aesthetically pleasing weld, you will want to choose to push the weld since it is easier to keep a steady bead across the welding point.  Knowing both of these techniques is crucial for MIG welding so you can be ready for the given situation.  There are certain welders that require you to pull the torch where as others require you to push.  On top of that, you may be asked to weld in an awkward position that only allows you to push or pull the torch.  To ensure confidence you will want to practice both techniques while maintaining proper grip and tip positioning.

Step 7: Possible Mistakes

· You hold the torch too far from the metal.  Remember that touching the wire tip to the metal is the only way to melt the metal and create a bond.  Now you do not want to push the tip too far into the metal and break the wire tip.  It is all about finding your touch for it and being consistent every time you weld.

· You move the torch too fast or slow.  Being able to adjust for your wire speed is key when welding.  If you move too fast your weld will be tall and thin in which turn will be weak.  Whereas on the other hand, if you are too slow you run the risk of breaking the wire tip or burning through your work piece.  Again this all comes down to finding what feels comfortable for you.  Be sure to get your share of practice in before welding professionally.