HOW TO WELD WITH A MIG WELDER
Welding with gas can look difficult, so we’ll make it easy by breaking it down step by step.
CHOOSING YOUR WELDER
We bought an Eastwood MP140i multi-purpose welder because it can do flux core, MIG, TIG, and stick welding.
We picked up our MP140i on a Black Friday special, for $500. It comes with everything you need to start MIG welding except for welding gas. You could go with something less expensive, like a flux welder, but flux runs hotter. If you plan to weld automotive sheet metal, flux is possible but more difficult. Flux will also result in more splatter, leading to additional work.
If you go with flux we suggest a welder that can be upgraded like the Eastwood MIG 90. You can get the MIG 90 flux only or the MIG 90 with the upgrades for MIG welding. We also have a full comparison of welders for cars here.
SAVE 10% w/code THEBUILD10 on www.eastwood.com
WHERE CAN I FIND WELDING GAS?
The first thing you're going to need is welding gas. The MIG calls for using 75% argon and 25% CO2 welding gas. The easiest way to find welding gas is to open Google or Apple Maps, type "welding gas" and see what comes up.
Here are some options near you that might carry welding gas.
Select Tractor Supply Stores - Call to confirm
Select Northern Tool Stores - Call to confirm
We ended up purchasing a 40 CF size cylinder from Airgas. They had much larger sizes, but since we won't be welding every day, 40 CF is fine.
While you’re at it buy a welding cart too. You can pick one up from Eastwood.com using our 10% off discount code of BUILD10 during checkout.
HOW TO SETUP A WELDER
First, you need to hook up the gas and regulator. The Eastwood MP140i or MIG 90 with MIG upgrades includes a regulator. The regulator is required to adjust the pressure of the gas as it flows from the cylinder through the welder and out of the stinger.
The regulator attaches by screwing it into the gas cylinder. All the gas attachments are made to seal without any pipe sealing or threading, so DON’T use any.
Once your regulator is tightened with a hand wrench hook up the hose from the regulator to the welder. Repeat tightening everything with a wrench and don’t over-tighten the fittings.
You can then use soapy water to check for any gas leaks once you open up the gas cylinder.
The Eastwood also comes with a few other essentials to get you started. You have your ground attachment, which attaches in a specific placement for MIG, and another attachment for your stinger or welding gun.
Depending on the type of welding you're doing, these will go into different places, so refer to the manual to check where the ground gets plugged into. This will vary depending on if you are MIG or flux welding.
FEEDING THE MIG WIRE
Inside the welder, you need to feed the MIG wire into place. The Eastwood came with 0.023 wire size, perfect for the variety of sheet metal sizes we'll be welding.
Remove the bigger spool
Put in the smaller one using washers, springs, and nuts to secure it.
Hold the spool and feed the wire through the tensioner.
Release some tension on the nut holding the wire spool as necessary.
Lock the tensioner into place.
Turn the machine on and pull the trigger to feed the wire through the stinger. Note: you don’t need gas yet and make sure there’s nothing to ground to.
Clip the wire out of the stinger nozzle feed to leave about 1/2 inch out.
SAFETY FIRST
For safety, you'll need a flame-retardant shirt, welding gloves, a welding mask, a welding blanket, and a fire extinguisher.
HOW TO SETUP MIG GAS
One of the easiest steps is turning on the gas.
Crank it to the open position
Adjust the regulator to the correct setting, which the manual suggests around 20 PSI.
Pull the trigger without making any contact to make sure gas and wire is flowing.
Clip any excess wire from the nozzle feed and leave about 1/2 inch out.
MIG SETTINGS
We're going to be welding some thinner sheet metal first, around 22 gauge, which calls for a voltage set to six and a wire feed set between 2.5 and 4.
Set the voltage knob to 6 and a wire feed set between 2.5 and 4.
Attach your ground clap to the piece of metal
Bring your stinger to the welding location, lower your mask with the appropriate shade set, pull the trigger, and release
For thin sheet metal you’ll want to tack weld. Meaning you want to weld in small increments. As you increase your thickness of metal, you’ll want to also increase your voltage and wire feed. For thicker metal say 16 gauge and up you can run a contineous weld instead of tacking.
PRACTICE WELDING
Continue to practice by tack welding or spot welds. You can also use a copper backplate as a heat sink to help prevent blowouts. Use different thicknesses of material. Try butting, overlapping, and tree joints.
