We weld every day, with all three processes, on everything from sheet aluminum to 1" mild steel plate. The internet has a lot of opinions about MIG vs TIG vs Stick. Here's the working welder's version — when each one is actually the right call.

MIG (GMAW) — the production workhorse

Use MIG when: high deposition rate matters, fit-up is decent, cosmetics aren't critical, and material is 16-gauge or thicker. MIG is fast, consistent, and easy to automate or robotize. For 99% of structural steel work, weldments, and mid-thickness fab, MIG is the answer.

Avoid MIG when: you're welding thin aluminum (it punches through), you need root passes on pipe, or you're welding outdoors where wind blows shielding gas off the puddle.

TIG (GTAW) — when it has to be right

Use TIG when: you need cosmetic weld appearance, full penetration on thin material, weld on aluminum, stainless, titanium, or magnesium, or certified pipe work. TIG gives you total control of the puddle and the lowest heat input per inch of weld.

Avoid TIG when: you have a lot of weld to put down on a tight schedule. TIG is slow. A fillet weld that takes 90 seconds in MIG can take 6 minutes in TIG.

Stick (SMAW) — outdoors, dirty, and forgiving

Use Stick when: you're welding outdoors, on rusty or painted material, on heavy plate, or in field repair where you can't bring a gas bottle. Stick doesn't care about wind, surface contamination, or position.

Avoid Stick when: you're welding under 3/16" material (you'll burn through), need cosmetic appearance, or are working on aluminum or stainless where MIG/TIG are clearly better.

The decision matrix we actually use

Material / Situation	Best process
Aluminum sheet (under 1/8")	TIG (or pulsed MIG)
Aluminum plate (over 1/4")	Pulsed MIG or spray-arc MIG
Stainless cosmetic / food grade	TIG with back-purge
Stainless structural	MIG with tri-mix
Mild steel structural fab	MIG (75/25 gas)
Mild steel pipe root pass	TIG root, then MIG/Stick fill & cap
Field repair on heavy equipment	Stick (7018 for strength, 6010 for dirty)
Outdoors with wind	Stick or flux-core (FCAW)
Robotic / high-volume	MIG, occasionally pulsed TIG for cosmetics

Pre-heat and post-heat

For anything over 3/4" thick, or any high-carbon steel (4140, 4340), or any welding on cast iron or tool steel — pre-heat is not optional. Skipping it gives you cold cracks 24–72 hours after welding, which is the most expensive way to find out you skipped a step. Our rule: thick, hard, or critical → pre-heat.

Robotic welding: when it earns its keep

Robots are great when the part is repeatable, the volume is over a few hundred per year, and the joint geometry is consistent. They're terrible at one-offs, fit-up correction, and parts with stack-up. We use robots for our production weldments and humans for everything else.

What to spec on your weldment drawing

Weld symbol per AWS A2.4 (not just "weld here")
Process callout if it matters (TIG required for cosmetics)
Filler material (ER70S-6, ER308L, etc.)
Inspection level (visual, dye-pen, x-ray, ultrasonic)
Pre-heat / post-heat requirements
Distortion control notes if the part is long or thin

We MIG, TIG, stick, and robot-weld in Jacksonville every day. If you have a part that needs welding and you're not sure which process to spec, send the drawing — we'll tell you what we'd do and why. Full welding capabilities here.