Level 3 · TIG: aluminum, stainless, and welds you meant to look like that

Everything below this level is about getting metal to stick together reliably. Level 3 is where the weld itself becomes part of the design. It is also where the honest answer to "should I?" is genuinely "it depends what you want to make" rather than "yes, eventually".

TIG is not an upgrade to MIG in the way MIG is an upgrade to flux-core. It is a different craft with different strengths, and a great many extremely competent home fabricators never own a TIG machine because nothing they build needs one.

What TIG actually is, and why it is harder

In MIG, the wire is both the electrode and the filler — it melts into the joint as it feeds, so one trigger controls everything. In TIG, the electrode is tungsten and it does not melt. It exists purely to make the arc. The filler is a separate rod you hold in your other hand and feed into the puddle manually, and the amperage comes from a foot pedal.

That separation is the whole point. Because heat and filler are independent, you can put exactly as much heat into a joint as it needs and exactly as much metal as it needs, which is what makes TIG work on 22-gauge stainless where a wire process would blow straight through.

It is also why it is hard. Three inputs at once, plus the discipline never to let the tungsten touch the puddle — which contaminates it and means stopping, grinding and starting again.

AC versus DC: the one specification to get right

If you read nothing else on this page, read this. DC TIG welds steel and stainless very well and cannot weld aluminum usefully. AC TIG welds aluminum.

The reason is oxide. Aluminum instantly grows an oxide skin that melts at roughly three times the temperature of the aluminum beneath it. On AC, the electrode-positive half of each cycle blasts that oxide apart — the cleaning action — while the electrode-negative half does the heating. That alternation is exactly what aluminum needs, and it is why AC/DC machines cost more than DC-only ones.

So the buying question at Level 3 is not really which machine. It is: will you ever weld aluminum? If yes, buy AC/DC and accept the price. If genuinely never, a DC machine will save you real money and weld steel and stainless beautifully. AC versus DC TIG works through it properly, and TIG welders for aluminum covers the machines if the answer is yes.

The controls that actually change the weld

Budget AC/DC machines advertise a long list of adjustable parameters. Three of them earn their place.

AC balance sets how much of each cycle is spent cleaning versus penetrating. More cleaning for dirty or anodized aluminum; more penetration for thick, clean material. This is the control you will actually reach for.

AC frequency tightens or widens the arc cone. Higher frequency gives a narrower, more focused arc, which matters on fillets and tight corners.

Pulse alternates between a high and low current many times per second. On thin material it lets you put in enough peak heat to fuse without accumulating enough average heat to burn through.

Everything else on the panel is refinement. Check which of those three a machine actually publishes before you compare prices — a long parameter list that omits AC frequency is a shorter list than it looks, and the name-brand machines no longer concede that ground.

Everything that is not the machine

TIG has the longest supporting-cost tail of any level here. You need 100% argon, a regulator and a bottle. You need tungsten, and a dedicated grinding wheel for it, because sharing a wheel with steel contaminates the tip and ruins the arc. You need filler rod in the right alloy for the metal, which means stocking more than one. And you need a helmet that triggers reliably at low amperage — a budget lens that fires fine on a 100-amp MIG arc can fail to darken on a 15-amp TIG arc, which is exactly the situation you do not want to discover experimentally. See auto-darkening helmets for what to check.

On power: a 200-amp class machine on a 240-volt circuit is the normal home setup, and the circuit comes first. What size breaker a welder needs is the page to read before you order anything, and circuit work belongs to a licensed electrician.

The signal that you have outgrown Level 3

This one is not about welding at all. It arrives when you notice that the slow, annoying part of every project is no longer joining metal but cutting it — when you are spending forty minutes with an angle grinder to produce a shape you could draw in thirty seconds. That is Level 4 · Plasma, and it is the only rung on this ladder that is about shaping rather than joining.

Two pages for after the machine arrives

How to get good TIG welds is for the moment the amperage is right off the settings chart and the bead still comes out wrong — the five variables that decide a TIG bead, in the order they go wrong, plus the start-and-stop defects no chart covers.

And does TIG welding need gas answers the question that stops more TIG purchases than price does. Short version: yes, always, and "TIG welding flux" is not a way around it.

Most people who get this far end up choosing between two machines, so Eastwood TIG 220 versus AHP AlphaTIG 200X compares them row by row — the torch in the box, the duty-cycle inversion, and which of the two tells you what it does on a 110-volt circuit.

And when the shortlist is down to a single machine rather than a pair, our Everlast PowerTIG 210EXT review takes one of them apart on its own — the 60% duty cycle quoted at the full 210 amps rather than further down the range, which of its nine programs and three AC waveforms you will actually use, and the foot pedal and argon regulator that ship in the box.

AC is the decision you cannot undo

Almost everything else about a TIG machine can be fixed later with money. A scratchy torch is replaceable; a missing foot pedal is a purchase. AC output is designed into the machine, and it is the only way to weld aluminum — the electrode-positive half of each cycle strips an oxide skin that melts far hotter than the metal beneath it. The best AC TIG welders ranks the aluminum-capable machines on AC balance, AC frequency and published duty cycle rather than on amperage.

The machine most budget aluminum searches end at gets a page of its own: the AHP AlphaTIG 200X review takes its published figures apart, including the 60 percent duty cycle at the full 200 A that beats machines costing three times as much. If the work is steel and stainless only, a DC machine does the same job for less — the best TIG welders for home use is scoped to that.

One machine, two outlets

Most people buying a first TIG welder do not yet have a 240 V circuit, and the machines built for that gap are sold as dual voltage. The catch is that most of them publish one amperage and leave you to assume it applies on both supplies — it does not. The best dual voltage TIG welders ranks the field on whether the maker prints a separate figure for each supply. Three of the seven do, and where they do, the 120 V number lands between 55 and 65 percent of the 240 V one.