MIG vs TIG for Automotive and General Fabrication: What the Available Evidence Can Decide

What this evidence set can and cannot settle

Every process-specific figure in this set describes one process on its own terms. One source rates GMAW excellent for thin sheet in clean thin-material applications⁸; another describes TIG as a tungsten-electrode process used on very thin metal of 0.5–4 mm, largely for aerospace components¹⁸.

Neither tests the two processes on the same joint, gauge or current, so you cannot read a head-to-head winner out of them. That matters before you write a specification.

If your job is clean thin-gauge carbon or stainless steel, the MIG side of the comparison is documented well enough to specify against. The TIG side is not: the set gives TIG a working description and a thickness range, and nothing you could put in a cost model.

Plan to source the TIG numbers separately rather than inferring them from the MIG figures.

Is MIG's deposition rate high enough for your throughput?

MIG feeds a continuous wire electrode, and the reported output is tied to a specific consumable: GMAW with ER70S-6 solid wire is given as 3–10 kg/hr at 93–97% deposition efficiency⁸. A second source puts MIG at 2–8 kg/hr for carbon and stainless steel in large-scale production¹⁸.

Both bands sit in the low-to-mid single digits, and they overlap between 3 and 8 kg/hr¹⁸ (supplier-reported figure). Use that overlap as your planning band, not as a guaranteed rate.

Neither source states the current, wire diameter or travel speed behind its figure, so the rate your shop actually achieves on your joint is a question for the shop. Ask for the deposition rate on your wire diameter and current before you commit a cycle time to a customer.

Can you price TIG against MIG from this evidence?

No. The only TIG description here ties it to precision bevel welds in 0.5–4 mm metal, largely aerospace work¹⁸, and gives no deposition figure at all.

There is nothing in the set to set beside MIG's 3–10 kg/hr⁸ or 2–8 kg/hr¹⁸. So a TIG quote cannot be benchmarked on rate from these pages.

If TIG is on the table for a thin or cosmetic joint, require the shop to state its own TIG deposition rate and the conditions behind it Current, filler, joint type — before you compare the two routes on time. Without that number, any TIG-versus-MIG productivity comparison you write is unsupported.

Which process for thin sheet, and at what gauge?

Both processes are described as usable on thin material, but the descriptions do not meet. MIG carries a capability rating — excellent for thin sheet⁸ — while TIG carries a thickness range, 0.5–4 mm, for precision bevel work¹⁸.

A rating and a range are different kinds of claim, and no source tests the same gauge with both processes. That leaves you without a crossover thickness.

No source in this set establishes a minimum reliable gauge for either process, or a thickness above which one should be chosen over the other. For a clean thin-gauge automotive or enclosure part, MIG is the route the evidence describes directly⁸.

For a joint thin enough that burn-through is the risk, ask the shop which process it would run at that gauge and on what trial evidence.

Surface condition and cleanup: what to write into the RFQ

The set contains no contamination tolerance and no MIG-versus-TIG bead or cleanup comparison, so surface condition has to become a stated requirement rather than an assumption.

The nearest evidence is on shielding gas for a different process: in FCAW, a 75% Ar/25% CO2 mix gives lower spatter and improved bead appearance than pure CO2, which raises spatter 15–30%²⁸. That is a gas effect within one process, not a MIG-versus-TIG finish result, and it does not transfer as one.

• ✓State the as-received surface condition (mill finish, oiled, painted, rusted) on the drawing and ask the shop what prep it requires for MIG.
• ✓Ask whether the quoted price includes spatter removal and post-weld cleaning, and to what finish standard.
• ✓Request a sample or first-off weld on your actual gauge and surface condition before the run is released.
• ✓Confirm the shielding gas and wire specification the shop will run, and that they match the filler classification called out.

Base metals and consumables you can specify

The consumable side is documented for one combination only: ER70S-6 solid wire with GMAW, reported at 3–10 kg/hr and 93–97% deposition efficiency⁸. MIG is described more generally as a continuous wire electrode with inert gas for carbon and stainless steel¹⁸.

TIG is described by its tungsten electrode and its thin-section precision role¹⁸, with no filler metal or gas named. If your part is carbon or stainless steel, you can specify MIG and name ER70S-6 as the wire the reported figures belong to⁸.

If it is aluminum or an exotic alloy, this set gives you nothing to specify from — neither process is described on those materials. Ask the shop for its procedure and a test weld on the actual alloy before you release the drawing.

Equipment and skill expectations to carry into the RFQ

The only cost ranking in the set is relative and covers equipment only: GMAW sits at medium equipment cost, with FCAW at medium–high and SMAW at low⁸. There is no TIG equipment figure, and no labour, gas or amortisation data for any process.

Treat MIG as a medium-equipment-cost route on that ranking⁸ and leave TIG's capital and training cost to be quoted. When you compare bids, ask each shop to separate equipment-related charges from labour hours, so the two processes are being compared on the same basis rather than on a single blended rate.

Where the sources disagree on MIG deposition rate

Two sources give different MIG deposition bands under different stated conditions, and neither states current or wire diameter, so the disagreement cannot be resolved from these pages. Quote against the overlap and confirm the figure with the shop.

Before you request a quote

• TIG deposition rate (kg/hr) at any current or filler diameter — no source in this set gives one, so no MIG-versus-TIG rate ratio can be calculated.
• Cost per foot of weld for either process (consumables, labour, gas, equipment amortisation) — the set carries no welding cost data.
• Minimum reliable gauge, and single-pass versus multi-pass thickness thresholds, for MIG and TIG.
• Contamination tolerance (rust, oil, paint) and required surface prep per process.
• A direct MIG-versus-TIG bead profile, spatter and post-weld cleanup comparison.
• TIG filler metal and shielding gas requirements, and welding of aluminum or exotic alloys by either process.
• TIG equipment cost, setup cost, and operator skill or training requirements.
• Welding procedure qualification, inspection methods, defect rates and applicable code clauses for MIG and TIG.