Mig Welding Tips For Beginners 

By: Timothy Welch

May 27, 2019

After 12 years of welding experience, I have learned welding tricks to help improve beginners who are starting out in MIG welding.

Here is what you’re going to learn in this post:

  • Table of contents
  • Be safe
  • How to prep your metal
  • Drive, wire, and tips
  • Watch your puddle
  • Aww, the sound of bacon
  • Watch for weld defects
  • Organize your work station

Arc Welding is the most economical way of joining two or more metals together permanently to create a single piece. Arc welding by definition is “a technique in which metals are welded using the heat generated by an electric arc.” Tig, Mig, Stick, and Pipe are all types of arc welding. Mig welding (Metal Inert Gas) is the easiest of the 4 to develop a technique for.

Be Safe

Let’s always start with safety first. In any type of arc welding, like MIG welding, it gives off a visible and intense ultraviolet radiation (UV radiation) and infrared radiation. If there is any skin exposure than the arc will burn unprotected skin just like the sun’s UV radiation. A weld arc heat can range from 5,432 – 36,032 degrees Fahrenheit (3,000 – 20,000 degrees Celsius). Depending on your settings.

Make sure you wear the right type of welding gloves, the splatter can burn through and melt thin gloves with a rubber elastic, so I recommend using leather gloves to protect your hands. Also, a protective reflector would be helpful for those hot jobs with high settings.

Arclight can reflect off of walls, ceilings, and metal surfaces. Looking directly at the welding light can burn your eyes causing “flash burn” which burns the cornea. Symptoms of flash burn may include bloodshot eyes, light sensitivity, blurred vision, and eye irritation like a burning feeling. If problems occur, see a medical doctor for proper treatment. Always wear your welding hood while welding to prevent flash burn in the eyes, wear safety glasses to prevent any flying debris such as weld splatter from getting in your eyes. Eyesight is a very valuable thing.

Tips: Since the arc from the welder gives off UV radiation just like the sun, use sunblock for your face, neck and any other unprotected upper body skin. This will help prevent having a painful sunburn.

Mig welding is more forgiving with dirty metal such as light rust, unlike Tig, where the metal has to be as clean as possible. Having surface rust, liquid, debris, and paint will cause porosity in the weld. Porosity looks like holes in your weld, almost like bug holes in wood. Always get into the habit of cleaning the surface of the metal to help prevent porosity from occurring.

Use a wire wheel attached to an angle grinder to remove any oxides from the steel

When using a flapper disc you don’t want to have your angle grinder tilted too far up, this will cause dips in your steel, instead, you want to lift the back end about 2” slightly above the metal surface. This will I sure no dips while cleaning your metal.

Caution:

When using an angle grinder you need to use a grinding shield to keep sparks away from your face. Grinding shields will also protect your face from flying debris such as pieces of the broken cutting wheel, sparks, and metal slag.

Tips: You can use a flapper disc attached to an angle grinder to help clean surface defects

The functionality of your welding machine is second to the most important point. Without a proper functioning machine, your welds aren’t going to show your proper skills. What a lot of beginners don’t pay attention to are the drive wheels. Depending on your machine, you could have two or four wheels with grooves on top to allow your wire to be pulled by. Depending on the size wire you have is going to determine what drive wheels you are going to use. Some drive wheels have only one size groove, the wire size will be on the side of the wheel. Others will have two sizes with each groove size to match the wire.

Since the wire is curled around the spool, your contact tips are used to keep your wire straight long enough to hit the metal. Depending on the size of the wire you are using, it will depend on the size of the contact tip you are going to use. The contact tips are made for a specific size wire. Also, make sure you have the correct size nozzle to match the length of the tip

Tips: Look on the side of the welding spool to know what size of wire you have, match the correct contact tip by looking on the bottom side of the tip to see what size tip you have.

Watch Your Puddle

Knowing how to read your weld is the skill that welder must have, having the right settings, speed, and centering your weld takes practice, practice, and more practice. You can not rush your weld, you have to keep your weld centered and the same size from end to end. Going too fast in your weld will result in your weld will have waves throughout the length of your weld. Look at the picture below to see the waves the weld

In order to prevent this from happening you have to keep a steady pace. Keep checking your welds by using your weld gauges to ensure all your welds are the size required. This brings me to my next point…

Aww, the sound of Bacon

Now many of you may be wondering, what does bacon have to do with welding? The correct parameters on your welding machine will mimic the frying sound of bacon frying. A skilled welder can listen to the sound of the weld and tell if the setting is correct or not. When you adjust your welds, the sound changes too.

The display of a welding machine will vary with different machines, but the voltage and wire speed will be what is adjusted.

Below is a chart by Lincoln Electric

According to millerwelds.com, they say “one way to check your parameters is by examining the weld bead. Its appearance indicates what needs to be adjusted.

Good weld: Notice the good penetration into the base material, flat bead profile, appropriate bead width, and good tie-in at the toes of the weld (the edges where the weld metal meets the base metal).”

Picture from millerwelds.com

“Voltage too high: Too much voltage is marked by poor arc control, inconsistent penetration and a turbulent weld pool that fails to consistently penetrate the base material.”

Picture by millerwelds.com

“Voltage too low: Too little voltage results in poor arc starts, control, and penetration. It also causes excessive spatter, a convex bead profile and poor tie-in at the toes of the weld.”

Picture by millerwelds.com

“Travel speed too fast: A narrow, convex bead with inadequate tie-in at the toes of the weld, insufficient penetration, and an inconsistent weld bead is caused by traveling too fast.”

Picture by millerwelds.com

“Travel speed too slow: Traveling too slow introduces too much heat into the weld, resulting in an excessively wide weld bead and poor penetration. On thinner material, it may also cause burn-through.”

Picture by millerwelds.com

Watch For Weld Defects

No matter how skilled of a welder you are, if your weld has defects, no company will be impressed by your work. Here’s a list and pictures of some common weld defects:

Undercut Welds

When this weld flaw occurs, the weld metal fails to fill in that grooved area, resulting in a weak weld that is prone to cracking along the toes.

Tips: To eliminate undercut, reduce current and slow travel speed, or simply reduce the size until you have a puddle size you can handle.

Porosity 

Porosity occurs when having a lack of shielding gas and penetration. If you see your welds looking like this then you need to grind out these welds and starting over

Tips: To prevent porosity, check all gas sources to ensure proper gas flow

Weld Splatter

Weld splatter is essentially droplets of molten material that are generated at or near the welding arc. To help avoid spatter from occurring when you MIG weld, you should properly set your MIG welder. This will only reduce the amount of splatter.

Tips: Adjust either your wire speed or your voltage, this will correct your splatter problem. Also, splatter can be caused by having your wire stick out too far, this is the distance between your contact tip and your metal. You want your wire stick out to be ¾”, by having excessive stick out you increase splatter and bigger problems like porosity. Porosity occurs here because of a lack of gas and a lack of penetration. 

Cold Roll or Cold Shuts

Cold roll or cold shuts, occurs when there is no fusion between the weld metal and the surfaces of the base plate. Either the weld puddle is too large (travel speed too slow) and/or the weld metal has been permitted to roll in front of the arc.

Tips: Turn up your voltage or lower your wire speed to correct this from occurring. 

Organize Your Workstation

An organized work area is more productive, safer, and helps reduce work stress. To help with these issues, most companies implement kaizen or 5S which teaches in a workplace “a place for everything and everything in its place”.

The 5S’ are Sort, Set in Order, Shine, Standardize, and Sustain.