Intro to MIG welding


Note: This is just a very general overview of the Welding Intro class curriculum, primarily used as a prompt when instructing the class live. This article is (obviously) not meant to replace being properly trained on the equipment.


  • it’s super cool and feels awesome
  • welders build the world
  • very employable skill
  • can look incredibly awesome
  • it’s a lightning gun!
  • very easy to get ok at it; hard to master
  • might be the only reason to keep you around in the apocalypse


You need to bring/wear:

  • Closed toe shoes
    • It’s a good idea and also a shop-wide rule
  • Long pants
    • Not just for splatter; you can get sunburn too.
  • Non-synthetic fabrics
    • Cotton may burn, but synthetics melt
  • We provide weld jackets, gloves, and helmets


  • general metal handling (heavy, sharp, hot, rusty); common types of gloves
  • arc flash, going blind, testing your hood
  • burning the shit out of yourself, jackets and leather (welding arc can reach 24,000 degrees science / 43,000 degrees freedom)
  • sparks and spatter, catching shit on fire, awareness of what’s around your hood
  • electrical dangers; describe average voltage/amperage ranges. 1A per thou average.
  • zinc poisoning, fume control, ventilation (and how it affects shielding gas)
  • gas cylinder storage, pressure container dangers
  • Where are the fire extinguishers?
    • One above the grinding table, another outside the entrance to the metal shop
  • First aid kits:
    • Weld-specific kit with burn treatments above grinding area
    • Main first aid station in woodshop


  • NOT going to cover stick, tig, brazing, spray transfer, or other processes here.
  • only covering flat position; there is also vertical, overhead, pipe, etc.
  • not going into detail on joint types; fillet, lap, groove, plug, butt, corner, tee, edge, etc
  • Also only focusing on mild steel, no fancy materials like stainless or aluminum.
  • MIG welding = hot glue. Super easy to get OK at, will take you a few years to actually get good.
  • overview of how a MIG welder works; basic circuit, DCEP/reverse polarity, ground clamp, gun, ER70S6 wire, nozzle, spool, gas, etc.


  • Spinny sharp thing safety; loose hair and clothing, face shielding, keep hands away from blades, cut metal is sharp and hot
  • chop saw some angle iron coupons
  • bench grinder on the edges, mention beveling
  • clamp and angle grinder to remove mill scale from plate; what is mill scale?
  • Now we’re ready to weld


  • how to turn the welder on
    • Check ground plug
    • how to set gas flow – 15-25 CFM to start, adjust as needed
  • set wire feed rate and amperage
  • appropriate wire stick-out distance
  • how to shut the welder off
    • Coil wires and leave on hooks
    • Turn off gas
    • Replace dust cover


  • lay plate on table, have students tack edges down
  • demonstrate warping with some flat bar or rod; this is why we tack first. Mention average thermal expansion/contraction rates for steel
  • cover gun positioning, posture, dry run; lay a 1″ bead down; watch the weld puddle closely, this is where the action happens
  • stick a couple coupons to the plate, attach some stuff stuff to other stuff
  • practice fillet welds; demonstrate stringer vs weave
  • general practice time. describe what we’re looking for in good welds; penetration, porosity, buildup
  • If we have adequate time and materials, show blow-through and how to fix it; bridging gaps


  • grind off our tacks, clean up the table
  • put everything away, sweep
  • discuss where to acquire metals in town
  • resources on how to get better
  • Q&A


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