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A 240V TIG welder is useful when workshop jobs call for clean, controlled welds: stainless brackets, mild-steel fixtures, aluminum parts or thin sheet that would be easy to burn through with a less precise process. The right machine depends less on its maximum amperage than on the materials you weld, the thicknesses you see most often and the electrical supply available.

What 240V means in a workshop

In the U.S., these welders usually connect to a 240V circuit, often through a NEMA 6-50 receptacle. Check the machine’s plug, input-current rating and manual before buying; a 240V outlet alone does not guarantee that the circuit can support the welder at full output. A 50A circuit is common for larger machines, but installation requirements vary. Have an electrician confirm the wiring and breaker rather than swapping a receptacle onto an undersized circuit.

Also check whether the welder needs single-phase power, what input voltage range it accepts and whether it can run on 120V as well. A dual-voltage machine is convenient for occasional work away from the main outlet, but usually has lower output on 120V. It does not turn a household outlet into a dependable high-amperage TIG supply.

AC/DC or DC-only?

For aluminum, look for AC TIG. Alternating current helps break up the aluminum oxide layer during welding; DC-only TIG machines are generally the wrong purchase if aluminum is a regular job. AC/DC machines also weld steel and stainless on DC, so they cover more workshop work, though they cost more and have more settings to learn.

If you weld only steel or stainless, a DC TIG machine can be the sensible budget choice. It can make excellent welds on those materials and avoids paying for an AC section you may never use. For occasional aluminum repair, consider whether you can outsource the work before stretching the budget for AC/DC.

Compare the main options

Those thicknesses are practical starting points, not guarantees. A 1/4-inch steel joint may need multiple passes, beveling or a higher-amperage machine. Thin sheet may require less amperage and good fit-up more than a bigger power source.

Features that matter more than peak amps

Look at rated duty cycle: a rating of 200A at 20% means the machine is designed to weld for 2 minutes in a 10-minute period at that output, followed by cooling time. At lower amperage, the duty cycle may rise considerably, so compare ratings at the current you expect to use rather than relying on the headline maximum.

For aluminum, adjustable AC balance and AC frequency are useful for tuning oxide cleaning and arc behavior, but they are not substitutes for clean material and correct technique. For all TIG work, check the available amperage range, foot-pedal support, post-flow control and whether a torch, regulator, ground clamp and consumables are included. A bare machine can look like a bargain until you add a compatible torch, pedal and gas gear.

High-frequency start gives a non-contact arc start, which helps avoid tungsten contamination. Lift-arc start is simpler and can work well, but requires touching the tungsten to the work before lifting it. If the machine has no foot pedal, verify whether it supports a torch switch or fingertip control and decide whether that arrangement suits your work.

What to buy

For a steel-and-stainless-only bench, start by comparing 240V DC TIG welders. Favor a stable low-amp range and a complete, compatible torch setup over an impressive peak-amp figure. A cheaper DC machine is fine when aluminum is off the job list and you can live without premium arc controls.

For regular aluminum fabrication, compare 240V AC/DC TIG welders. Check the manual for AC output and duty cycle, not just the word “aluminum” in a listing. If the machine is sold as dual voltage, verify its AC/DC capability and rated output on 240V; product descriptions can make feature differences easy to miss.

Plan for gas and setup

TIG needs shielding gas, typically argon for ordinary steel, stainless and aluminum work. A cylinder, regulator or flowmeter, hose, torch consumables and tungsten are part of the real purchase cost. Flow rates around 15–20 cubic feet per hour are common in many indoor setups, but torch size, cup and drafts change what is appropriate. Too little gas can leave a porous, discolored weld; too much can create turbulence that pulls air into the shield. Keep the work out of drafts rather than simply turning the flow up.

Clean the joint before welding. Remove oil, paint and rust from steel; use dedicated stainless brushes and abrasives for stainless; and remove oxide from aluminum with a clean stainless brush. Contaminated tungsten often shows up as an unstable arc or inclusions. Stop, regrind it and clean the work instead of trying to weld through contamination.

Final checks before ordering

Confirm the outlet and circuit, plug type, input requirements, warranty support and what accessories are actually in the box. Check that replacement consumables are easy to source. If your projects are mostly thicker mild steel and speed matters more than appearance, a MIG welder may be a better primary purchase; TIG shines when control, access and finish justify slower travel and more setup.

Budget for a welding helmet with a suitable TIG low-amperage setting, gloves, protective clothing and ventilation. TIG is still capable of producing ultraviolet radiation, hot metal and harmful fumes, particularly from coatings. Choose the machine around your normal work and electrical supply, then spend time learning torch angle, filler timing and fit-up. Those habits will improve welds more than buying a machine with a larger number on the front panel.