Here is an updated chart including gasless MIG welding:

Technique	Full Name	Description	Usage	Drawbacks
MMA	Manual Metal Arc Welding	Uses a flux-coated consumable electrode held in the welder’s hand. An electric arc forms between the electrode and workpiece. The flux coating melts to form gas and slag to protect the weld.	Versatile, can weld all metals, including outdoors. Lower cost.	Slow, requires more skill, slag removal needed after welding.
MIG	Metal Inert Gas Welding	Continuously fed consumable wire electrode feeds through welding gun, with inert shielding gas flowing around the arc to protect the weld.	Faster welding of light metals like aluminum. Easier to learn. Good for automation.	Limited metals can be welded. More equipment needed.
MAG	Metal Active Gas Welding	Similar to MIG but uses active shielding gases that chemically interact with the weld pool.	Faster welding of steel. Deeper weld penetration.	More expensive shielding gases. Porosity defects can occur.
GMAW	Gas Metal Arc Welding	Encompasses both MIG and MAG welding. A consumable electrode wire feeds continuously. Shielding gas flows around the arc.	Very versatile - good for many metals with proper electrode wire and shielding gas. Higher deposition rates.	More expensive equipment. Requires shielding gas.
FCAW	Flux Cored Arc Welding	Wire contains a flux core that generates shielding gas so no external gas needed.	Lower equipment cost by avoiding external shielding gas. Good penetration on steel.	More spatter and slag. Limited to mild steel welding.

Cittadhammo: how do I recognize a spool of fcaw

Claude: Here are some ways to recognize a spool of flux-cored wire for FCAW welding:

Check the labeling/packaging

• It should be clearly labeled as “flux-cored” or “FCAW” wire. The AWS wire classification will be something like E71T-1. Look for the seam lines
• FCAW wire will have two parallel seam lines running along the length of the wire. This is where it was formed around the flux core. Solid MIG wire has no seam. Color
• FCAW wire is often more grayish/tan in color versus the shiny copper color of solid MIG wire. The flux core gives it a duller appearance. Weight
• FCAW wire feels heavier than solid MIG wire of the same diameter due to the dense flux core. Diameter
• FCAW wires are often larger diameters since the flux core displaces some of the metal. E.g. 0.045” flux-cored wire contains less actual weld metal than 0.045” solid MIG wire. Examine ends
• You can sometimes see the flux core by examining the wire end, especially if you knock the wire on something to expose the center. The flux will be a grayish powder. Run a bead
• If you’re unsure, try welding a short bead. FCAW will have more spatter and slag compared to solid MIG wire.

So in summary, look for the labeling, seam lines, color, weight, size, and slag/spatter characteristics to identify FCAW flux-cored welding wire. Knowing the differences allows you to select the right wire for your welder.