Learn To MIG Weld In A Flash
MIG welding is a skill that can come in handy in a farming operation. Your equipment inevitably will break during your busiest seasons, and having the ability to quickly weld and fix equipment in the field could be a game changer.
MIG delivers an excellent combination of speed and versatility, and is one of the easiest welding techniques to learn. To learn this skill it will take a little patience, a bit of concentration, and a few hours of dedicated practice. We asked our friends at HTP to walk us through how to get started with MIG welding.
MIG Explained
MIG stands for Metal Inert Gas. This type of welding uses electricity to melt and join together pieces of metal. Compared to any other method of welding, MIG welding is the easiest way to weld.
MIG welding was developed for welding aluminum during World War II as a way to increase productivity. Many different materials can be welded with a MIG welder. The welding wire (electrode) and shielding gas types will vary depending on the type of material you are working with.
Think of MIG welding like using a crafter’s hot-glue gun. In welding, a continuous consumable wire electrode (the glue stick) along with a shielding gas are fed through a welding fun (the glue gun). A short circuit is created, producing intense heat that melts the metal, mixing together, and fusing when cooled.
MIG welding can be used to weld a wide range of metals including steel and stainless steel, aluminum, and cast iron, as well as braze steel.
Ins & Outs
MIG welding machine is made up of four basic pieces: the power source, a tank of shielding gas, a welding gun, and a ground cable. Each of these are crucial to the welder’s success.
Power Source - Located on the exterior of the power source are the operating controls for the welder. Depending on the unit, these may include an on/off switch, welding amperage and voltage displays, spot and stitch controls, and transformer adjustment.
Remove the cover and you’ll find, essentially, two machines: the power supply side consisting of the transformer, rectifier, and condensers; and the control side consisting of the circuit board, wire feed system, main relay, and solenoid valve.
Gas Tank - The tank, normally located behind the cabinet, holds the gas that is used to shield the weld as you work. The flow meter on the tank reduces the pressure in the tank (over 2000 PSI) to a usable pressure, allowing you to precisely monitor the gas flow.
Welding Gun - The welding gun’s trigger sends a signal to the machine to start the welding current, start the wire feed motor, and turn on the gas. A copper contact tip at the end of the gun takes the welding current the machine produces and transfers it into the wire. The tip is replaceable and must match the diameter of the wire you’re using. The gas nozzle directs flow of the shield gas around the weld, protecting the weld from the atmosphere.
The Ground Clamp - The clamp completes the circuit between the welder, the gun, and the metal being welded.
Start with Safety
The light generated by MIG welding is extremely bright, so you’ll need a good welding helmet. Auto-darkening units are preferable because they darken automatically when the welding arc is struck.
A pair of heavy-duty gloves and protective leather gear is also important. These items offer protection from any molten metal that may splatter.
Finally, only work in a well-ventilated area and always keep a fully charged CO2 fire extinguisher handy.
Getting Started
One of the most important steps in MIG welding is making sure that the surfaces you are going to weld are clean. A dirty surface could cause contamination, and create an unstable arc. A very good rule to remember is the more time spent cleaning, the less time spent welding.
First, make sure the power switch is in the “on” position and the grounding clamp is properly attached. Make sure you have opened the valve on the tank and that you have adjusted your flowmeter. Select the correct heat setting for the thickness of material you will be welding, and then, using a piece of scrap metal, set adjust the wire feed rate.
There’s a relationship between the wire speed and the welding sound. If the speed is set too low, you’ll hear a hissing noise and the wire will melt before it hits the surface of the work. If the feed rate is too high, you’ll hear it spit and pop. A steady buzzing noise is what you should listen for – this is where you should set your wire speed.
Since the electrode and gas are automatically fed through the MIG torch, the basic technique for MIG welding is fairly simple. Maintain a consistent position and orientation between the gun and the area being welded. The result will be a smooth, stable welding arc.
Tack Welding
When working with two separate pieces of material you should begin with a tack weld to avoid panel separation. For a tack weld, you want to weld for about 2 seconds – just long enough for a molten puddle to form and join the two pieces of metal together. The tack welds should be two to three inches apart.
After the tack welds are completed, rest the gun slightly on the work and maintaining a 45-degree angle slowly guide the gun along the material you're welding in a smooth, constant motion. You always want to keep the welding wire in sight so you can see exactly where you are laying the bead. Control the bead width by moving the welding gun faster or slower.
Stitch Welding
Stitch welding is just as easy as the tack method. In the stitch weld mode the machine is automatically welding and pausing. What the machine is doing is overlapping tack welding. You move the welding gun when the machine pauses. This type of welding helps prevent warpage and burn through because the gas helps cool the weld.
Stitch welding, in effect, is just a series of overlapped tack welds that join together to form one continuous bead – it looks like a row of fish scales.
Once you’re able to lay a bead and stitch weld, you can continue on to techniques such as plug and spot welding or other, more advanced procedures.
Source: HTP America, Inc. • 800-USA-WELD • www.usaweld.com
