If you're getting a welding job quoted by multiple shops, you've probably heard "MIG" and "TIG" tossed around like they're interchangeable—they're not. Choosing between these two processes affects your project timeline, final cost, and the quality of welds you'll actually receive. Here's what you need to know to make an informed decision.
The Core Difference
MIG (Metal Inert Gas) welding feeds a wire electrode continuously through a gun, making it faster and more forgiving for beginners. TIG (Tungsten Inert Gas) welding uses a non-consumable tungsten electrode and requires a foot pedal for amperage control, demanding more skill but delivering cleaner, stronger welds on thinner materials.
Think of MIG as the practical workhorse for production jobs; think of TIG as the precision tool for detailed or critical work.
Speed & Turnaround Times
MIG wins decisively on speed. A fabricator can typically lay down beads 2–3 times faster with MIG than TIG because the wire feeds automatically and there's minimal setup between joints. For a straightforward structural steel frame or box tubing assembly, expect:
- MIG completion: 3–7 working days for moderate projects
- TIG completion: 7–14 working days for the same scope
That speed difference matters when you have a tight deadline. However, if your job is aluminum, stainless steel, or requires cosmetic-grade welds, TIG's slower pace is often non-negotiable.
Cost Breakdown
MIG typically costs 30–50% less per hour than TIG because shops charge for labor time, and MIG moves faster. Here's a realistic range:
- MIG labor: $65–$120/hour (depending on region and shop size)
- TIG labor: $90–$180/hour (specialized skill premium)
For a 40-hour fabrication project, that's roughly $2,600–$4,800 for MIG versus $3,600–$7,200 for TIG. Material costs (gas, wire, electrodes) are similar, though TIG jobs sometimes require more finishing work (grinding, polishing), which adds labor.
Equipment investment is another story. If you're comparing quotes from shops, this rarely appears on your invoice—it's baked into hourly rates. But if you're considering in-house welding, MIG machines cost $1,500–$4,000, while TIG setups run $3,000–$8,000+.
When to Choose MIG
Pick MIG if you need:
- Fast turnaround on mild steel structures, frames, or tanks
- Cost-conscious budgets with reasonable quality standards
- Production runs where consistency matters more than cosmetics
- Thicker materials (⅛ inch and up) where heat penetration is straightforward
MIG excels on outdoor equipment, agricultural implements, and general structural work. Most job shops use MIG as their baseline because the return on labor investment is strong.
When to Choose TIG
Choose TIG for:
- Aluminum and stainless steel (MIG struggles with aluminum without specialty setups)
- Thin-wall tubing or sheet metal (< 1/8 inch) where precision prevents burn-through
- Cosmetic welds that need a polished appearance without grinding
- Critical joints in aerospace, food-grade, or pressure vessels where weld integrity is non-negotiable
- Custom art pieces or decorative ironwork where visual quality is the product
TIG also produces superior welds in poor positioning—overhead or vertical joints are cleaner and stronger with TIG than MIG in most cases.
What to Ask Your Fabricator
When requesting quotes, specifically ask:
- "Which process do you recommend for my material and thickness?" (A good shop won't push one method just to simplify their workflow.)
- "Are you quoting labor time, or do you have a flat rate?" (This prevents surprises.)
- "What's your typical turnaround for this type of job with your preferred method?"
- "Will the welds need finishing (grinding, polishing), and is that included?"
Many shops use both processes on a single project—MIG for structural build-up, TIG for final finishing or critical joints. Don't assume you're locked into one method.
Finding the Right Shop
If you're comparing welding services, Mercoly helps you gather quotes from multiple verified fabricators, see their equipment and capabilities, and read customer feedback—all without cold-calling ten shops individually.
Frequently Asked Questions
Q: Can I use MIG on all my mild steel work? Yes—MIG handles mild steel from light gauge to ½-inch-thick material reliably and economically. Only switch to TIG if cosmetics matter or you have thin gauge work under 1/16 inch.
Q: Why is my TIG quote so much higher if the actual welding takes longer? TIG demands certified welders with years of experience and muscle memory; the skill premium justifies the cost. Additionally, TIG often requires cleaner material prep and may need finishing work included.
Q: Can a fabricator switch processes mid-project if needed? Absolutely—professional shops do this constantly. Root passes might be TIG for quality, cap passes MIG for speed, or vice versa. Always ask if they recommend combining both approaches.
Compare welding services on Mercoly to get accurate quotes from shops equipped for your specific project needs.