Auto body and garage welding: sheet metal, floor pans and gates

Q: What is the best welding process for auto body work?

MIG with shielding gas (75/25 argon/CO₂) and .023–.030 in (0.6–0.8 mm) solid wire. It gives the most control on 18–22 gauge body sheet.

Free guide · The Welder's Forge · updated September 2026

Plenty of people pick up a welding machine for the garage, not for a career. You want to patch a rotted floor pan, replace a rocker panel, build a gate or fix a trailer without paying a shop for every weld. This section collects the guides for that work, with the same numbers as the e-book.

Quick answer

For auto body and thin sheet (18–22 gauge), start with MIG with shielding gas (75/25 argon/CO₂), .023–.030 in (0.6–0.8 mm) solid wire and spaced tack welds instead of one long bead. For gates, railings and thicker steel, a 3/32 in (2.4 mm) E6013 stick electrode handles most of the job.

Where to start

Panel burns through or warps? The tack-and-cool method and the copper backing bar are in welding thin sheet metal without burning through.
Rusted-out floor? Follow the patch from cutting to rust protection in welding car floor pans.
No machine yet? Compare processes in best welder for beginners, then see inverter vs transformer welder.
Building a frame? Start with welding square tubing, then put it to work in how to weld a gate.
Before the first arc: pick the right lens in the auto-darkening welding helmet guide and dress properly with the welding PPE checklist.

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Which process for which garage job

Process	Best for	Learning curve	Gas cylinder needed?
MIG (GMAW)	Auto body, thin sheet, fast work, beginners	Low to medium	Yes with solid wire; no with self-shielded flux-cored wire
Stick (SMAW)	Gates, railings, structures, thick steel, outdoor work	Medium	No
TIG (GTAW)	Stainless, aluminum, fine work and a perfect finish	High	Yes (argon)

Table 16.1 of the e-book The Welder's Forge.

Mistake number one

Too much heat on thin sheet. Turn the settings down, tack in a spaced pattern and let the metal cool between tacks. Mistake number two is welding over dirt: paint, rust, seam sealer, body filler and zinc ruin the bead.

Know what not to weld

Do not weld on brake lines, fuel tanks and fuel lines, suspension parts, steering parts, seat-belt anchors or airbag areas unless you are qualified and following the vehicle maker's repair procedure. Modern unibody cars use high-strength steels that heat can weaken. When in doubt, take the job to a qualified collision repair shop.

These guides are reference material. They do not replace hands-on training with someone who can watch your technique.

Guides on this topic

Welding thin sheet metal without burning through (or warping)Stitch tacks, thin wire and a copper backing bar Welding car floor pans: patch panels step by stepAssess, cut, patch, plug weld and rustproof the repair Best welder for beginners: MIG, flux-core, stick or TIG?MIG, flux-core, stick and TIG compared, plus 120 V vs 240 V Inverter vs transformer welder: the differencesWeight, AC or DC, electrodes and household power How to weld square tubing without blowing holesWall thickness, corners, 45° cuts and tack order How to weld a gate, step by stepMeasure, square, tack, weld in balance, hinge and paint Auto-darkening welding helmet: what shade to use and how to chooseShade by process, ANSI Z87.1 and what to check Welding PPE: what to wear before you strike an arcHelmet to boots: the right PPE for every part of the body

Frequently asked questions

What is the best welding process for auto body work?

MIG with shielding gas (75/25 argon/CO₂) and .023–.030 in (0.6–0.8 mm) solid wire. It gives the most control on 18–22 gauge body sheet.

Can I weld car body panels with a stick welder?

On 20–22 gauge panels it is very hard: the puddle is large and burns through. Stick starts to make sense on heavier steel, such as 1/16 in (1.6 mm) and up, with a small rod and short tacks.

What welder should I buy for garage projects?

For sheet metal and cars, a MIG welder that accepts shielding gas. For gates and thicker steel, a stick inverter. Read the nameplate for input voltage (120 V or 240 V) and match the circuit to it.

Is it safe to weld a car at home?

It can be, if you disconnect the battery, support the car on jack stands, remove fuel and upholstery from the work area and keep an extinguisher close. Leave safety-critical parts to a qualified shop.

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The e-book The Welder's Forge covers stick, MIG/MAG and TIG from the first arc to the shop floor, with reference tables and technical figures, in plain American English.

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