How to TIG Weld

How to TIG Weld series (The Complete Beginner-to-Advanced Guide)

Setting up a new TIG Welding Machine

CK worldwide MT200

Primeweld TIG225 setup

What Is TIG Welding?

Textbooks, and authority sites like millerwelds.com state that TIG welding uses a non-consumable tungsten electrode to create an arc that melts the base metal.

Don’t let the term non-consumable confuse you because tungsten electrodes are definitely a consumable.

The tungsten is not consumed into the weld. Or at least its not supposed to.

Tungsten is consumed by repeated sharping just like a pencil.

Filler metal also called “TIG rod” is added separately by hand, and shielding gas (usually argon) protects the molten weld puddle from exposure to air which causes contamination .

What makes TIG unique from other welding processes like MIG, Stick, and Flux core:

Separate control of heat and filler
Extremely clean welds
Precise puddle control
Works on thin and thick materials
Ideal for aluminum, stainless, and carbon steel, titanium, magnesium, copper, pot metal, chromoly, nickel alloys, and others.

Because of this precision control, TIG welding is used in:

Motorsports & fabrication
Aerospace
Food-grade stainless work
Pipe welding
Artistic and precision fabrication

What You Need to TIG Weld

Before striking an arc, let’s cover the essentials.

TIG Welder also called a TIG welding machine and sometimes refered to as a TIG power source.

For the best experience, You’ll need a TIG machine capable of both DC and AC current:

If all you have is a DC TIG welder, that is ok to get started with but since AC/DC tig welding machines have become so affordable, I would strongly recommend an AC/DC tig welder so that you won’t be limited.

DC output (for steel and stainless)
AC output (for aluminum)
Foot pedal or fingertip amperage control

Both the PrimeWeld 225 and 325 tig welders, and the CK worldwide MT200 come equipped with a foot pedal and there are plenty of tutorials here to show how to get the most out of either machine

Torch, Cables, and Controls

Common TIG torch sizes:

17 series – general purpose air cooled (most common)
26 series – heavier duty air cooled
20 series – compact water-cooled
9 series - compact air cooled

A torch setup typically includes:

Torch body
Collet
Collet body or gas lens
Insulator heat shield
Cup
Back cap

A gas lens setup is strongly recommended because it improves gas shielding and makes seeing the puddle easier due to increased electrode extension.

Shielding Gas Basics

Most TIG welding uses 100% argon. Don’t even waste your time trying to use MIG gas (75/25)

Typical flow rates:

General rule of thumb is 2 to 3 CFH per cup size
10–15 CFH for a #5 cup
20–30 CFH for a #10 cup

Helium or argon/helium mixes are sometimes used for thicker aluminum, but pure argon is perfect for learning and will likely be the only gas you ever need for TIG.

Good shielding is critical — poor gas coverage causes:

Dirty welds
Gray or black discoloration
Porosity
Tungsten contamination

Tungsten Selection (Simple Version)

Tungsten is what creates the arc. The type you use matters.

Common tungsten types:

2% Lanthanated (blue) – excellent all-around choice for all metals
Rare earth / E3 (purple) – very stable and versatile
CK worldwide LaYZr - very stable and versatile
Thoriated (red) – DC only (less popular now due to reported safety concerns)

Tungsten prep basics:

Cut with grinder or diamond wheel…don’t snap to avoid splitting
Grind lengthwise, not around
Sharp point for carbon steel & stainless
Balled or rounded tip for AC aluminum (or let the machine form it)

A clean, properly shaped tungsten makes TIG welding dramatically easier.

Choosing Filler Rod

Filler metal should match the base material or be designed to be compatible with base metal being welded.

Filler metal in stock at weldmonger.com

Common filler rods:

Carbon Steel and chromoly TIG rod

Stainless TIG rod

ER308L
ER309
ER312

Aluminum TIG rod

4043
5356

Rule of thumb:

Use smaller filler for thin material
Keep filler clean
Keep the hot tip of the filler rod inside the shielding gas

Understanding Polarity: AC vs DC

DCEN (Direct Current Electrode Negative)

Welding current flows from negative to positive so DCEN current flows from the electrode to the base metal.

Used for:

Carbon Steel and Chrome-moly
Stainless steel
Nickel alloys
Titanium
Other metals like copper, cobalt alloys,

Provides good penetration and stable arcs.

AC (Alternating Current)

Used for:

Aluminum
Magnesium
Pot metal
Cast iron using aluminum bronze filler metal

AC alternates between electrode negative and electrode positive providing:

Cleaning action (oxide removal)
Penetration

Modern machines let you adjust AC balance and frequency.

AC balance lets you fine-tunes cleaning vs penetration.

AC frequency lets you adjust the arc focus

Amperage Basics (Simple Rule of Thumb)

A good starting rule:

Steel: ~1 amp per thousandth
Stainless: ~0.8 amps per thousandth
Aluminum: ~1.2 amps per thousandth

Example:

1/8" steel → ~125 amps
1/8" stainless → ~100 amps
1/8" aluminum → ~150 amps

Use the pedal or amperage control to fine-tune while welding.

Joint Preparation Matters More Than You Think.

Remember The 3 C’s

Clean
Clean
Clean

Before welding:

Remove oil, grease, paint, rust, mill scale
Clean stainless and aluminum with dedicated brushes
Wipe with acetone if needed
Fit joints tightly

Clean metal = stable arc + better looking welds.

Torch Angle, Arc Length, and Shielding hot tip of filler rod

These three fundamentals control almost everything.

Arc Length

Keep it tight
About the diameter of the tungsten or less
Long arc = wide, dirty, unstable puddle

Torch Angle

Aim for about 10–15° push angle
Keep the tungsten pointed in the direction of travel
Torch angle can be very forgiving provided Arc Length is good.

Shielding the hot tip

Keeping the hot tip of the filler rod inside the argon envelope will prevent excess oxides in the puddle
A gas lens cup can help due to larger argon area
Keep the tip inside the argon but far enough from the arc to prevent the tip from melting and balling

Feeding Filler Rod Correctly

Key principles:

Keep hot tip of filler rod inside the shielding gas
Dab at the front edge of the puddle
Don’t melt the rod with the arc
Feed rhythmically

Many beginners struggle here — practice feeding rod without welding first.

Feeding filler rod Tips Video

How to Start a TIG Weld

Position torch
Establish arc
Form a small molten puddle
Add filler
Begin moving forward

Avoid stabbing motions. Think melt → add → move.

How to Stop a TIG Weld Cleanly

A clean finish matters.

Slowly taper off amperage
Add a little extra filler rod at the end
Let the puddle solidify under gas coverage and allow post flow to run out
Don’t snap out abruptly

This prevents craters and cracking.

Common TIG Welding Mistakes (and Fixes)

Dirty or gray welds

→ Improve gas coverage and cleaning

Tungsten dipping

→ lengthen arc, slow down, stabilize hands

Porosity

→ Check gas flow, leaks, clean metal more thoroughly

Cracking

→ Add more filler rod, especially at the start of the weld, reduce heat input, preheat thick metal, improve joint design

Overheating

→ Back off amperage, move faster, pause to let cool between passes.

( these are general troubleshooting guidelines …each situation is unique)

How to Practice TIG Welding - A Proven Structured ABC, 123 method

Practice should be structured, not random.

Recommended drills in order:

Focus on:

Consistent puddle size
Smooth rhythm
Torch angle discipline
Clean stops and restarts

What to Learn Next

Once you understand the basics, move into material-specific guides:

How to TIG weld aluminum
How to TIG weld stainless steel
How to TIG weld carbon steel
How to set AC balance and frequency
How to choose tungsten and filler
How to use a gas lens
How to weld thin material
How to weld tubing and pipe

TIG welding is a skill built on control, patience, and repetition. You don’t need to rush it. Master the fundamentals, keep your setup clean, and practice with intention.

If you do that, the “stack of dimes” look becomes a byproduct — not the goal.

This page is your foundation. Everything else builds on it.

See the One Page TIG welding Rules of Thumb