This Video on Mig Welding Basics shows how to set up a mig welder along with arc shots of what incorrect settings look like
To MIG weld 11-gauge lap joints in carbon steel, you will need the right equipment and follow sound welding techniques.
Here's a step-by-step guide on how to do it:
Prep the metal: Remove any dirt, rust, paint, or coatings from the surfaces to be welded using a grinder. Light mill scale coatings like you see on 2 inch square tubing is no problem but heavier mill scale coatings need to be cleaned because short circuit mig welding has a tendency for lack of fusion when welding over heavy mill scale coatings.
Set up the MIG welder:Consult the welder's manual: Follow the manufacturer's instructions to set up the welder correctly, including the appropriate voltage, wire speed, and gas flow rate.Select the appropriate wire diameter: For 11-gauge carbon steel (approximately 1/8 inch thick), a 0.030 or 0.035-inch diameter wire is commonly used.
Choose the shielding gas: Carbon dioxide (CO2) or a mixture of CO2 and argon (C25) are typical shielding gases for short circuit mig welding of carbon steel. C25 is more popular and more versatile
Prepare for welding: Use C-clamps or other clamps to hold the workpieces firmly in place with no gaps while tack welding.
Welding technique: this is where an auto dark helmet really helps. Position the MIG gun at a 10-15 degree angle from perpendicular to the joint, pointing towards the heavier or bottom piece of steel.Establish the arc by pressing the trigger to initiate the welding arc while maintaining a steady motion.
Weld the joint: Move the MIG gun in a controlled and steady motion along the joint, slightly oscillating from one side to the other with very small movements. the movements could be just a slight side to side motion, a series of small cursive e's or similar pattern.
Watch the puddle: Observe the molten puddle, ensuring it stays centered over the joint. The puddle should be consistent in size and shape. There should be a smooth sizzle sound with short circuit mig with very little spatter.
Maintain a consistent travel speed to ensure a uniform weld bead.
maintain a consistent stick out distance. (stickout is the distance between the contact tip and the weld and should be 1/2" or less with short circuit mig weldng.