Article
How a TIG Welder Works and When to TIG Weld
Learn the basics of TIG welding in motorsports applications and the proficiency of a TIG welder on aluminum and chrome-moly.
Guide to TIG Welding Basics
Andrew Pfaller
When to TIG Weld
TIG welding, also known as gas tungsten arc welding (GTAW) is a precision welding process known for producing clean, high-quality welds on metals like steel, aluminum and stainless steel — making it essential for industries where weld integrity is critical.
How the TIG welding process works
In TIG welding, a non-consumable tungsten electrode in a handheld torch heats the metal while a shielding gas (commonly argon) protects the weld from contamination. Filler metal is added with a separate rod as the weld progresses.
Because TIG welding requires the use of both hands, operators often rely on a foot pedal or a torch-mounted amperage control to start, adjust and stop the flow of current.
Advantages of TIG welding
There are several benefits that TIG welding can provide when compared to other welding processes.
These benefits include:
Welds a wide range of metals
The TIG process can weld more metals and alloys than any other process. TIG welders can be used to weld steel, stainless steel, chromoly, aluminum, nickel alloys, magnesium, copper, brass, bronze and even gold. The TIG process can be used to weld everything from bike frames to door handles to automotive parts.
Produces high-quality, clean welds
With superior arc and weld puddle control, TIG welding creates clean welds — ideal for projects where appearances matter, such as aerospace and custom automotive work. Because the heat input is often controlled with a foot pedal or fingertip control, TIG allows you to heat up or cool down the weld puddle, providing precise weld bead control.
Cleaner welding process
Unlike MIG welding, TIG welding produces no sparks, spatter or slag, so there’s nothing to clean between passes. Because only the necessary amount of filler metal is added and the weld puddle is protected by argon shielding gas, TIG welding delivers a smooth, contamination-free finish.
One shielding gas for all applications
Argon can be used for all TIG applications, for all metals and thicknesses. This streamlines gas maintenance in the shop or manufacturing facility. While it is possible to use helium or specialty blends, these are not typically necessary.
Welding in all positions
TIG welds can be made in all positions — flat, horizontal, vertical and overhead — so TIG is perfect for welding roll cages or out of position.
How to choose a TIG welder
Choosing a TIG welder can be an exciting endeavor, but for some it might be overwhelming.
Here are a few considerations that can help guide you in selecting a suitable product for your needs.
Material type
Start by identifying the materials you plan to weld.
- For steel or stainless steel, a DC-only TIG welder is sufficient.
- If you plan on welding aluminum or are not sure what materials will be encountered, choose an AC/DC TIG welder for maximum flexibility.
Material thickness
Most welding power sources can handle common material sizes, but it’s important to match the machine to the thickness you’re working with.
- Thin materials: Choose a welder with fine control settings or adjustable parameters for better precision.
- Thick materials: Look for a machine with high peak amperage to ensure proper penetration.
Input power
Before choosing a machine, consider the power available at your worksite. If your available power doesn’t match the machine’s requirements, it can limit your options. For example, a high-amperage TIG welder may need three-phase power, which isn’t always accessible in smaller shops or residential settings.
- Single-phase power: Common in residential locations and small businesses.
- Three-phase power: Typical in industrial applications where heavier usage is required.
Portability
Portability is critical for certain applications. Historically, welding equipment was large and heavy, limiting mobility. With advancements in inverter technology, modern equipment has been designed to eliminate the size and weight barriers and provide the ability for a person to carry it or easily move with a cart accessory.
User profile and application
Finally, several other use-case factors are grouped together, so it’s helpful for you to identify as either a personal user, small business or heavy user.
TIG welder setup
Before starting, always read and follow your machine’s Owner's Manual and precautionary labels for complete safety, setup and installation instructions and procedures. The following diagram and instructions show a typical TIG welding system and connections.
Connect torch
When using an air-cooled or water-cooled torch, use the adapter from your accessory package and plug the torch into the front of your machine. Also connect your gas hose and regulator.
Connect remote control
Plug in your foot pedal or fingertip control to the machine.
Connect work clamp
Plug in your work clamp (also called a ground clamp) into the machine. Clamp the other end to your workpiece or worktable.
Select polarity
- Aluminum: Set amperage to AC.
- Steel/Steel Alloys: Set to DC TIG or DCEN.
Prepare tungsten
Grind your tungsten to a point using a 200-grit or finer wheel (designed for tungsten only to avoid contamination). When welding on aluminum, the tungsten will form a ball — repoint if it grows to the same diameter as your tungsten. Grind in the long direction and make the point roughly two and a half times as long as the diameter. Watch this video on tungsten prep:
Assemble torch
Loosen the back cap and remove the 3/32-inch diameter tungsten from your torch. Remove the nozzle and copper collet pieces, then reinstall the collet and collet body into the torch and tighten. Put the nozzle back onto the torch.
Install tungsten
Place the tungsten into the collet, leaving about 1/8 to 1/4 inch exposed (not more than the nozzle diameter which is also called the cup). Tighten the back cap.
Check and connect power
Make sure the power supply you are connecting to matches the rating of your machine (see rating label on unit). If your machine is supplied with a plug, connect to the correct outlet. You may need to purchase a plug to match your receptacle. If your machine is not supplied with a plug, follow the Owner's Manual for wiring instructions.
Selecting the right tungsten for TIG welding
Tungsten size, type, and preparation can have a significant effect on the weld quality.
When selecting tungsten, consider:
- Material type
- Material thickness
- Your TIG machine
Each tungsten alloy is identified by a color band painted on one end.
2% ceriated (gray): A versatile, all-purpose tungsten that can be used for AC and DC TIG welding on steel, stainless steel and aluminum. It offers easy arc starting, good arc stability and long life.
2% lanthanated (blue): Ideal for DC TIG welding and can offer precision for very specific applications.
Pure (green): Traditionally used for AC TIG on legacy transformer equipment. However, modern inverter-based TIG welders can result in a lack of arc starting or poor arc starting characteristics when using green tungsten. (Ceriated and lanthanated are recommended over pure alloy.)
All About Tungsten in TIG Welding: Types, Selection and Use
Ron Covell explains the different TIG tungsten options.
Tips for beginner TIG welders
Always check the Owner’s Manual for complete safety precautions and procedures, and make sure you have the necessary safety equipment and appropriate clothing for welding.
Here are a few TIG welding basics to help you get started:
TIG torch placement: How to hold for a clean weld
Hold the TIG torch in your hand at a 70- or 80-degree angle. Raise the torch so that the tungsten is off the workpiece no more than 1/16 to 1/8 inch. Don't let the tungsten touch the workpiece or it will contaminate your material and you will need to regrind your tungsten.
Foot pedal control: How to master heat input
Practice controlling the heat with the foot pedal to see the weld puddle increase and decrease. Ideally, you want your weld puddle to be about 1/4 inch wide. Keep your puddle size consistent so it doesn't grow, shrink, spread or narrow while you are welding.
Adding filler metal: How to get smooth welds
Pick up your filler metal in your other hand so it rests horizontally at a 15-degree angle from the workpiece — not pointed down. Heat up the base metal and gently dab the filler into the puddle. Dab in a quick, controlled manner so you don't leave large deposits.
To dive deeper into TIG welding best practices, read our full guide, "Welding Tips: The Secret to Success When TIG Welding."
TIG welding troubleshooting tips
Even seasoned welders experience challenges. If you run into issues while TIG welding, these common issues and solutions can help you get back on track.
Issue #1: Tungsten contamination
If your tungsten is melting into the weld puddle, use less current or use a larger tungsten size. Avoid touching your tungsten to the weld puddle — keep it 1/16 to 1/8 inch above the workpiece to prevent contamination.
Issue #2: Burning through tungsten quickly
If your tungsten is burning back or melting, it usually means too much heat is concentrated on the electrode or the shielding gas isn’t protecting it properly. This can happen for several reasons, including incorrect polarity, poor gas coverage or using the wrong tungsten size for your amperage. Even your machine settings — like balance control on AC TIG — can play a role.
Here’s what to check:
- Polarity: Make sure you’re on DCEN (electrode negative), not DCEP.
- Gas flow: Set shielding gas flow to 15–20 cfh and confirm the hose, valve and torch aren’t restricted. Use argon or an argon/helium blend.
- Tungsten size: For general TIG work, use 3/32-inch tungsten for up to 220 amps.
- Post-flow: Keep gas flowing 10–15 seconds after stopping the arc to prevent oxidation.
- AC TIG settings: Switch from pure (green) tungsten to ceriated (gray) or lanthanated (blue). If your machine has balance control, increase EN percentage to reduce heat on the electrode.
Issue #3: Porosity and poor weld bead color
Porosity and poor weld color usually mean contamination or gas issues. Before welding, check these key areas:
- Remove moisture: Make sure the base metal is dry and free of condensation. Purge air and moisture from gas lines.
- Clean surfaces: Eliminate grease, oil and moisture from both the base material and filler rod.
- Inspect connections: Tighten all torch and hose fittings to prevent leaks.
- Check gas flow: Maintain a steady flow of 15–20 cfh. Replace any defective hoses and look for leaks, cuts or pinholes.
Issue #4: Yellow powder or smoke on cup and/or tungsten discoloration
Yellow powder or smoke usually means your shielding gas or setup needs attention. Here’s what to check:
- Gas flow: Increase flow to 15–20 cfh.
- Gas type: Use argon or an argon/helium blend.
- Post-flow: Allow 1 second per 10 amps of weld current after stopping the arc.
- Match sizes: Use the correct tungsten and cup size for the joint. For general TIG work, that’s 3/32-inch tungsten with a #8 cup.
On aluminum, a tungsten that has been contaminated with steel and simply reground can also cause the rust color/discoloration near the welds due to the vaporization of the steel contamination from further up the tungsten.
Issue #5: Unstable arc
An unstable arc usually points to setup or contamination issues.
Start by checking these:
For DC TIG welding:
- Confirm polarity is set to DCEN (electrode negative).
- Inspect tungsten for contamination and regrind if needed.
- Keep arc length short and clean the base metal thoroughly.
- Cleaning tip: Some base materials now used come with coatings that are harder to identify. Additionally, galvanized material can cause similar issues when welding on it.
For AC TIG welding:
- Check arc length and ensure proper shielding gas.
- Use a clean, correctly prepared tungsten.
- Verify base metal cleanliness.
- Set frequency between 100–180 Hz.
- If arc instability persists, adjust balance control toward higher EN percentage, increase travel speed or add filler metal.
Issue #6: High frequency present — no arc power
This issue may be caused by an incomplete weld circuit or a lack of shielding gas. Check all cable connections and check for gas flow at the end of the torch. Also see if the gas cylinder is empty or the shut-off value is closed.
Issue #7: Arc wander
Arc wander usually means your arc isn’t focused or your tungsten prep is off.
For DC TIG welding:
- Keep arc length short — about 1/16 to 1/8 inch above the workpiece.
- Clean and sharpen the tungsten. If it looks frosted or gray, repoint and slightly truncate it.
- For heavy contamination, remove about 1/2 inch from the end before regrinding.
- Maintain proper gas flow (15–20 cfh).
For AC TIG welding:
- Use a pointed tungsten for inverter or square wave machines (it will round off during welding).
- Match tungsten size and type to the job.
- Maintain gas flow at 15–20 cfh.
- Adjust balance control toward higher EN percentage (70–90% EN is typical).
- Increase AC frequency for a narrower, more stable arc and deeper penetration.
- If rectification occurs, increase travel speed, adjust balance and add filler metal.
Issue #8: Arc won’t start or is difficult to start
If your arc won’t start or is hard to strike, it’s usually a setup or connection issue.
Here’s what to check:
For DC TIG welding:
- Confirm shielding gas is flowing.
- Tighten all cable and torch connections and ensure the weld circuit is complete.
- Use the correct tungsten type — ceriated (gray) or lanthanated (blue) — and the right size for your amperage.
- Check power supply settings and select HF start for non-contact arc initiation.
For AC TIG welding:
- Use ceriated or lanthanated tungsten and choose the smallest size suitable for the job.
- Make sure the work clamp is secure and cables are properly installed and tightened.
- Verify shielding gas flow and check for high-frequency loss. Inspect torch and cables for cracks or bad insulation.
- Check and adjust spark gaps if necessary.
Want more tips? Check out this guide for a complete troubleshooting walkthrough.
Getting started with TIG welding
Success with TIG welding starts with the basics: proper material preparation and the right tungsten selection. Combine these fundamentals with best practices and you’ll avoid many common issues. When problems do arise, knowing how to troubleshoot quickly will keep your welds consistent and high-quality. With preparation, attention to detail and a solid troubleshooting approach, you can achieve the results you want every time.
