Welding Types: MIG vs TIG vs Stick, Which to Use When

MIG (GMAW), TIG (GTAW), and Stick (SMAW) are the three common manual arc-welding processes, and the choice among them turns on speed, precision, material, and working conditions, indoor versus outdoor, clean versus dirty. All three melt base metal and filler into a weld pool under shielding, but they differ in how that pool is made and protected, which gives each its niche. This page compares the three and works through the trade-offs with concrete examples.

Typical parameters for mild steel run MIG short-circuit at about 17 to 21 volts and 90 to 150 amps (spray transfer at 24 to 28 volts and 180 to 250 amps), TIG at about 80 to 180 amps (roughly one amp per thousandth of an inch of thickness), and Stick with a 7018 rod at about 70 to 140 amps set by rod diameter. For structural steel, AWS D1.1 sets minimum fillet weld leg sizes by thickness, which governs joint design and inspection for coded work.

The core trade

The three processes trade speed, precision, and portability against each other, and no single process is best at all three. The comparison table above summarizes the trade across speed, control, material fit, and conditions.

Speed, precision, and portability

MIG feeds a continuous wire that serves as both electrode and filler, so it deposits metal fast and is easy to run, which makes it the most productive process for long welds on clean steel and aluminum indoors. TIG uses a non-consumable tungsten electrode with a separate filler rod added by hand, giving fine control of heat and filler for a clean, precise weld, which makes it the choice for thin material, stainless, and visible joints, at the cost of speed and skill. Stick uses a flux-coated electrode that carries its own shielding, so it works outdoors in wind and on dirty material that MIG and TIG cannot tolerate, which makes it the field and repair process, at the cost of a rougher weld and slag cleanup.

Why no single process wins

Each process gives up something the other two keep. MIG gives up portability and dirty-material tolerance for speed. TIG gives up speed for precision. Stick gives up a clean bead and high productivity for field ruggedness. The right choice is the process whose strengths match the joint and whose weaknesses the joint does not punish.

When to choose MIG

Choose MIG for fast, productive welding on clean steel and aluminum indoors. For example, a long production weld on a steel frame, where the joint is clean and sheltered and the weld is long enough to benefit from continuous wire feed, is a textbook MIG job, completed quickly with good penetration and a sound bead. Another example is an aluminum enclosure welded with a spool gun and ER5356 wire, where MIG’s deposition rate builds the weld faster than TIG could, at a productivity that suits production work.

MIG’s limits are burn-through on very thin material, where its high deposition can blow a hole, and the need for clean steel and indoor conditions, since contamination causes porosity and wind blows away the shielding gas. Within those limits, MIG is the most productive manual process, which is why it dominates fabrication and production welding on steel and aluminum.

When to choose TIG

Choose TIG for precision, cleanliness, and control on thin material, stainless, and critical or visible joints. For example, a thin stainless steel sheet welded with DC TIG and a matching ER308L filler produces a clean, narrow weld with minimal heat input and no spatter, which is essential where appearance and corrosion resistance matter and where a MIG weld’s heat would warp or burn the thin metal. Another example is a root pass on a pipe joint, where TIG’s control of penetration and bead shape produces a sound, smooth inside surface that a faster process could not match.

TIG’s trade-offs are speed and skill. It is slower than MIG for the same length of weld, because the welder adds filler by hand and controls heat with a foot pedal, and it demands more skill to coordinate torch, filler, and heat simultaneously. For the work that needs its control and cleanliness, that cost is justified; for long production welds on clean steel, MIG is faster and cheaper.

When to choose Stick

Choose Stick for outdoor, field, and repair work, and for dirty or rusty material. For example, a structural steel repair outdoors in wind, where the metal has some rust and the shielding gas of MIG or TIG would be blown away, is a clear Stick job, because Stick’s flux coating makes its own shielding and tolerates the surface condition. Another example is a field erection weld on a construction site, where portability, tolerance of conditions, and the ability to weld in any position make Stick the practical choice despite its rougher weld.

Stick’s trade-offs are a rougher weld that needs slag cleanup, lower productivity than MIG on long indoor welds, and difficulty on thin material, where its heat input is hard to control. For outdoor and dirty-material work, those trade-offs are acceptable, and Stick’s portability and tolerance are unmatched, which is why it remains the standard field process.

Worked examples

A few concrete joints show how the choice plays out. Consider a 0.040in (1mm) stainless sheet panel for a food-equipment enclosure: TIG is the clear choice, welding it cleanly with minimal heat input where MIG would burn through and Stick would be far too coarse. Consider a 1/4in (6mm) mild-steel frame weld in a shop: MIG is the choice, running the long bead productively on clean, sheltered steel. Consider a rusty steel gate repaired outdoors on a windy day: Stick is the choice, making its own shielding and tolerating the rust where MIG and TIG could not run. Each example turns on the same factors, the material, the thickness, and the conditions, and the right process follows directly from them.

A mixed example shows how a shop uses all three. A fabricator building a stainless tank, a steel frame, and a field repair uses TIG for the tank’s clean stainless welds, MIG for the frame’s long steel welds indoors, and Stick for the field repair outdoors, matching each process to the joint it does best rather than forcing one to do work it handles poorly.

Parameters and materials

Each process has a typical parameter range and a material fit, set by the physics of the arc and the shielding. Matching the process and its parameters to the material and thickness is how a sound weld is made, and the welding hub covers the detail behind each.

MIG transfer modes and gases

MIG runs short-circuit transfer at lower voltage and current for thinner material and spray transfer at higher voltage and current for thicker material. Short-circuit (about 17 to 21 volts, 90 to 150 amps) keeps heat low and suits sheet, while spray (24 to 28 volts, 180 to 250 amps) deposits metal fast on thicker plate. An argon-carbon dioxide blend is standard for steel, and straight argon for aluminum, with the gas chosen to match the material.

TIG current type and Stick rods

TIG runs direct current for steel and stainless and alternating current for aluminum (to clean the oxide), at a current roughly proportional to thickness (about 80 to 180 amps, roughly one amp per thousandth of an inch), with argon shielding. Stick runs at a current set by the rod diameter and type, with 7018 a common low-hydrogen rod for structural steel (about 70 to 140 amps by rod diameter) and 6010 or 6011 for root passes and dirty work.

Cost comparison

Cost follows productivity and skill. The right cost comparison matches each process to the work it does best, so the whole job costs less than forcing one process onto work it handles poorly.

Labor, productivity, and equipment

MIG is the most productive for long steel and aluminum welds, with continuous wire feed and relatively low skill, so its labor cost per length of weld is the lowest of the three for suited work. TIG costs more in labor for the same length, because it is slower and needs a more skilled welder, but it gives the cleanest result, which can be worth the cost where appearance or quality matters. Stick is cheap to set up and portable, with simple equipment, and its productivity sits between MIG and TIG on suitable work.

Setup and consumables

MIG and TIG carry the ongoing cost of shielding gas from a cylinder, plus wire or rod. Stick has no gas cost, since the flux provides shielding, but it consumes rods faster and leaves slag that takes labor to chip. For field work, Stick’s simple equipment also lowers transport and setup cost compared with a gas-shielded process that needs a cylinder and regulator.

Shielding and consumables

Each process shields the weld pool in a different way, and the shielding method is a large part of what suits each to its conditions. The choice of consumable, gas or rod, is part of the welding procedure and is matched to the material and the service.

Gas shielding for MIG and TIG

MIG and TIG rely on an inert gas flowed over the pool from a nozzle, usually argon or an argon blend, which displaces the air and prevents oxidation and porosity. This gas shield works well indoors but is easily disrupted by wind, which is why MIG and TIG are indoor processes unless sheltered. The gas is consumed continuously, supplied from a cylinder or bulk tank, and the flow rate and the nozzle design are set for the joint and the conditions. MIG also uses the wire itself as a consumable, fed continuously from a spool, which is both its filler and its electrode.

Flux shielding for Stick

Stick carries its shielding in the flux coating on the electrode. As the electrode melts, the flux burns to create a shielding gas and a layer of slag over the solidifying weld, which is chipped off after. Because it makes its own shield, Stick works outdoors in wind where MIG and TIG cannot, and the slag coating also tolerates some surface contamination, which is why Stick handles rusty or painted material better. The electrode is the consumable, replaced rod by rod, and the flux type suits the application: 7018 is a low-hydrogen rod for structural steel with good ductility and strength, while 6010 and 6011 are cellulosic rods that dig through contamination for root passes and repair work.

Positions, joints, and technique

The three processes also differ in the positions and joints they handle well, which affects where each is used. MIG’s continuous wire and high deposition suit flat and horizontal positions on longer welds, where its speed and productivity win, but it is harder to control in vertical and overhead positions, where the high-deposition pool tends to sag or drip. TIG’s fine heat control suits all positions, including the vertical and overhead work on thin material and pipe, where its precise pool management is essential, which is why TIG is the standard for pipe root passes and out-of-position precision work. Stick handles all positions competently, including vertical-up and overhead, which is part of why it remains the field and structural standard where positions are forced by the assembly.

Joints and technique also favor different processes. A long straight fillet or butt weld in flat position is a natural MIG job, run quickly with continuous wire. A root pass on a pipe groove, where penetration and a smooth inside surface matter, is a TIG job, run with careful control of heat and filler. A field repair on a rusty beam in a hard-to-reach position is a Stick job, run with a flux-coated rod that handles the conditions. The joint type, the position, and the access together point to a process, and an experienced welder or fabricator reads them together to choose the right one rather than forcing a process onto a joint it handles poorly.

How to choose

The decision comes down to four questions. Is the work indoors or outdoors, where Stick’s self-shielding matters in wind? Is the material thin, where TIG’s control is needed, or thicker, where MIG’s speed wins? Is the material clean or dirty, where Stick tolerates contamination the others cannot? And does the weld need to be clean and precise, favoring TIG, or productive and sound, favoring MIG? Answering these points to the right process in most cases, and the comparison table and the welding overview give the detail behind each.

Defects and inspection

All three processes can produce a sound weld, but each also has its characteristic defects, and inspection confirms the joint meets the design and the code. The defects below appear across MIG, TIG, and Stick, and the process choice changes which ones are most likely, not whether they can occur.

Defects and what to verify

• Porosity: gas bubbles trapped in the weld, common in MIG when shielding gas is low or disrupted and in Stick when the joint is damp or dirty. Verify by visual and radiographic inspection, and check the gas flow and the joint cleanliness.
• Lack of fusion: the weld metal sits on top of the base metal without melting into it, a risk on cold MIG or rushed TIG. Verify by bend testing, ultrasonic testing, or a cross-section macro-etch, and check the heat input and travel speed.
• Undercut: a groove melted along the toe of the weld that thins the base metal, common on high-current MIG and vertical Stick. Verify by visual inspection with a gauge, and reduce current or adjust technique to fill the toe.
• Distortion: the part bends from weld heat, worst on thin sheet with high heat input. Verify by measuring the assembly against the drawing after welding, and control it with clamping, sequencing, and minimized heat input.

For coded work, the inspection method, the acceptance criteria, and the welder’s qualification are documented against AWS D1.1 or the applicable code, so the joint can be trusted and audited rather than judged by appearance alone.