Guide to TIG Welding Basics

TIG welding tips 

TIG welding can produce clean, precise, aesthetically pleasing welds on a wide range of base materials — making it a good process for critical welds like those found in aerospace, food and beverage equipment fabrication, high-purity processing and motorsports applications.

But the TIG welding process can be more challenging to master than stick or MIG welding, making attention to detail important.

Included in this guide to TIG welding basics:

• What is TIG welding? 
• Advantages of TIG welding 
• How to choose a TIG welder
• TIG welder setup
• Selecting the right tungsten for TIG welding 
• Tips for beginner TIG welders
• TIG welding troubleshooting tips

What is TIG welding?

TIG stands for tungsten inert gas and is also known as gas tungsten arc welding (GTAW). In TIG welding, a tungsten electrode in a hand-held torch heats the metal being welded and a shielding gas (commonly argon) protects the weld puddle from airborne contaminants. The tungsten is a non-consumable and the filler metal is added via a filler rod in the operator’s other hand. The filler rod is added to the puddle of molten metal as the weld progresses. 

In addition to using both hands, the operator will often use a foot pedal or a torch-mounted amperage control for starting, modulating and stopping the flow of current.

The key to making a good TIG weld is heat control, which is governed by how you modulate the arc as it streams from the torch.

Advantages of TIG welding 

There are several benefits that TIG welding can provide when compared to other welding processes. These benefits include:  

• Ability to weld more 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. 

• High-quality, clean welds: With superior arc and weld puddle control, TIG welding allows you to create clean welds when appearances matter for the final product. Because the heat input is often controlled by pressing on a foot pedal, TIG allows you to heat up or cool down the weld puddle, providing precise weld bead control. This makes TIG ideal for cosmetic welds like sculptures and automotive applications. 

• Cleaner process: While TIG welding isn’t as productive a welding process as MIG welding, it is a cleaner process, with no sparks or spatter produced while welding and no flux or slag to chip off between passes. Because only the necessary amount of filler metal is added to the weld puddle, no spatter or spars are produced. And because the argon gas protects the weld puddle from contamination, no flux is required or used in TIG welding and there is no slag that covers the weld. 

• One shielding gas: Argon can be used for all TIG applications, for all metals and thicknesses. This streamlines gas maintenance in the shop or manufacturing facility. 

• 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 inside confined areas.

How to choose a TIG welder

Choosing a TIG welder can be an exciting endeavor but for some it might be overwhelming.  There are a few considerations that can help guide you in selecting a suitable product for your needs.

• Knowing the material type to be welded is imperative to having the right welding process. If you are going to be welding on steel or stainless steel, a DC-only TIG welder will be sufficient. If you plan on welding aluminum or are not sure what materials will be encountered, an AC/DC TIG welder would be a better option.

• The next factor will be the material thickness. Most welding power sources are capable of handling common material sizes. However, some machines provide more parameters that will allow them to give more control on thin materials. Conversely, for thicker materials the peak amperage or output will determine how thick a material you can weld.

• The input power you have available can be a limiting factor. Single-phase power is what most residential locations and small businesses have available, whereas three-phase power is common in industrial applications where heavier usage is required.

• Portability is critical for some applications. In the past, all welding equipment was large and heavy. With advancements in inverter technology, some equipment has been designed to eliminate the size and weight barriers and provide the ability for a person to carry it.

• 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 

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.

1. Connect torch: When using an air-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.
2. Connect remote control: Plug your foot pedal or fingertip control into the machine.
3. Connect work clamp: Plug your work clamp (sometimes referred to as a ground clamp) into the machine. Clamp the other end to your workpiece or worktable.
4. Select polarity: For aluminum welding, switch your amperage setting on the front panel to AC. For steel and steel alloy welding, switch your amperage setting to DC TIG or DCEN. (For stick welding, switch your amperage setting to DC Stick or DCEP.)
5. Prepare tungsten: Grind your tungsten to a point. When welding on aluminum, the tungsten will begin to form a ball. If the ball grows to the same diameter as your tungsten, repoint the tungsten. Grind in the long direction and make the point roughly two and a half times as long as the diameter. Use a 200 grit or finer grinding wheel. Do not use the wheel for other jobs or tungsten can become contaminated, causing lower weld quality. Watch this video on how to prepare a tungsten:
6. Assemble torch: Loosen the back cap and remove the 3/32-inch diameter tungsten from your torch. Remove the nozzle and copper collet pieces from your torch. Put the collet and collet body back into the torch and tighten. Put the nozzle back onto the torch.
7. Install tungsten: Place the tungsten into the collet. Leave about 1/8 to 1/4 inch sticking out of the collet (not more than the diameter of the nozzle, which is also called the cup). Tighten the back cap.
8. 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, plug it into the appropriate power outlet when you are ready to begin welding. You may need to purchase a plug to match your receptacle. If your machine is not supplied with a plug, connect according to the procedure provided in the Owner's Manual. Watch this video to learn more about setting up a TIG welder:

Selecting the right tungsten for TIG welding

Tungsten size, type and preparation can have a significant effect on the quality of your finished weld.

There are several considerations when selecting your tungsten. Material type, thickness and the machine you’re using all play a role in deciding which tungsten will provide you the best performance and results.

Each tungsten alloy is identified by a color band painted on one end.

• 2% ceriated (gray) tungsten is a good 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. 

• Pure (green) tungsten can be used for AC TIG on legacy transformer equipment, though the technology in today’s inverter-based TIG welders can result in lack of arc starting or poor arc starting characteristics when using green tungsten.

• 2% lanthanated (blue) tungsten is used for DC TIG welding and can offer precision for very specific applications.

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.

In addition, there are some TIG welding basics to help you get started.

• TIG torch placement: Hold the TIG torch in your hand at a 70- or 80-degree angle. Raise the torch so that the tungsten is off of 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: 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: 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.

Read this article for more TIG welding tips for beginners.

TIG welding troubleshooting tips 

If you run into issues while TIG welding, here are some common troubleshooting tips that can help: 

• Issue 1: Tungsten contamination
  • If your tungsten is melting into the weld puddle, use less current or a larger tungsten. To prevent contamination, it’s also important to avoid touching your tungsten to the weld puddle. Raise the torch so that the tungsten is off of the workpiece 1/16 inch to 1/8 inch. 

• Issue 2: Burning through tungsten quickly
  • First, be sure you are operating on electrode negative (DCEN) and not electrode positive (DCEP). Second, check that you have proper gas flow, which should typically be set at 15 to 20 cfh. Also make sure the hose, gas valve and torch are not restricted and that the tank isn’t out of gas. You should be using argon gas or an argon/helium gas blend. Using the wrong size tungsten can also be a common cause. General-purpose tungsten size is 3/32-inch diameter at a maximum of 220 amps. To avoid tungsten oxidation during weld cooling, keep your shielding gas flowing for 10 to 15 seconds after stopping the arc. If you’re running into problems with your tungsten melting back into the cup during AC TIG, change from a pure (green) tungsten to a ceriated (gray) or lanthanated (blue) tungsten. Also, if your power source has balance control, adjust the setting toward a higher EN percentage, which will reduce the heat concentrated on the electrode. 

• Issue 3: Porosity and poor weld bead color
  • Porosity in TIG welds can be caused by many factors. Make sure there is no condensation on the base metal; purge all air and moisture condensation from the lines and remove any condensation from the metal before welding. Remove all grease, oil or moisture from your base material and filler metal before welding as well. Next, check and tighten all fittings on your torch and hoses. Make sure there is adequate gas flow and adjust the flow rate as necessary (typically 15 to 20 cfh). Replace a defective gas hose and check your connections for any leaks, cuts or pin holes. 

• Issue 4: Yellow powder or smoke on cup and/or tungsten discoloration 
  • Your shielding gas flow rate may be too low. Increase the gas flow rate to 15 to 20 cfh. Also, be sure you are using argon gas or a helium/argon blend with adequate post flow of 1 second for each 10 amps of weld current. An improper tungsten size or cup size can also cause tungsten discoloration. Be sure to match your tungsten size and cup size to the joint being welded. General-purpose tungsten size is 3/32-inch diameter and a #8 cup. 

• Issue 5: Unstable arc
  • When DC TIG welding, an unstable arc can be caused by incorrect welding polarity (it should be set to DCEN for DC TIG), a contaminated tungsten, an arc length that is too long or base metal that is contaminated. 
  • When AC TIG welding, an unstable arc can be caused by incorrect arc length, improper shielding gas, a contaminated tungsten, contaminated base metal, an improperly prepared tungsten, or frequency that is set too low (100 to 180 hertz is acceptable). Excessive rectification in the base metal can also cause an unstable arc. To resolve this issue, increase your travel speed, increase the balance control toward minimum cleaning (a higher percentage) 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 
  • When DC TIG welding, arc wander can be caused by an improper arc length or a tungsten in poor condition. Lower the torch so the tungsten is off the workpiece 1/16 inch to 1/8 inch and be sure to clean and sharpen the tungsten. If the tungsten is improperly prepared or has a light gray frosted appearance on the end, this can also cause arc wander. Repoint and slightly truncate the tungsten. If it’s heavily contaminated, remove 1/2 inch of the tungsten using a high-speed abrasive wheel prior to final tungsten preparation. Also be sure gas flow is set at 15 to 20 cfh. 
  • When AC TIG welding, arc wander can be caused by a contaminated tungsten or contaminated base metal. Improper tungsten preparation can also be a culprit. With squarewave and inverter machines, use a pointed tungsten; the point will eventually round off after welding. Also be sure the proper size and type of tungsten is being used and that gas flow is set at 15 to 20 cfh. To resolve an incorrect balance control setting, increase the balance to reduce the cleaning (higher EN percentage). A normal balance control setting is 70% to 90% EN. Your frequency may also be set too low. Increase the AC frequency on machines equipped to do so to stabilize and direct the arc. Higher AC frequencies typically result in a narrower arc column and can help achieve deeper penetration. There also may be excessive rectification in the base metal. To solve this, increase travel speed and increase the balance to reduce the cleaning (higher EN percentage) and add filler metal. 

• Issue 8: Arc won’t start or is difficult to start 
  • While DC TIG welding, a lack of shielding gas, loose cable or torch connections, or an incomplete weld circuit can all cause arc starting problems. Also be sure to use the right tungsten size and type — choose a ceriated (gray) or lanthanated (blue) tungsten. In addition, check to make sure the power supply switch positions are correct. Select HF start for a non-contact arc starting mode and eliminate the need to touch or scratch the tungsten against the workpiece. 
  • While AC TIG welding, incorrect tungsten type or size can also cause arc starting issues. Use a ceriated (gray) or lanthanated (blue) tungsten and use the smallest tungsten size possible for the job. Make sure the work clamp is securely fastened to the work for a complete weld circuit and that cables are installed correctly and tightened. Also be sure the shielding gas is flowing properly and that you haven’t lost high frequency — check the torch and cables for cracked insulation or bad connections and check the spark gaps and adjust them if necessary. 

Read this article to learn more TIG welding troubleshooting tips.

Getting started with TIG welding

Proper material preparation and tungsten selection are key first steps toward success in TIG welding. Following some best practices and knowing how to troubleshoot some common issues can also help you achieve the results you want when using this process.