Skip to content
TIG Welding Technique: Walking The Cup Explained
TIG welding, or Gas Tungsten Arc Welding, is arguably one of the most challenging welding methods. However, high-skill requirements yield some of the highest-quality and most aesthetic welds.
Achieving high-quality welds is crucial in many applications, and one of them certainly is pipe welding. Many welders consider TIG welding pipes to be the most time-consuming and psychically demanding technique, but there is a solution.
The TIG welding technique, walking the cup, is one of the most widely used methods when TIG welding a root pass or other passes in pipeline welding. In this article, we'll explain what walking the cup is, how, why, and when to use it.
What Is Walking The Cup?
Walking the cup is a TIG welding technique used to weld grooved pipes and Tee joints. In this technique, you place the nozzle of the GTAW torch, often called the cup, onto the edges and feed the TIG filler rod inside the joint. Then, you start moving the cup across the joint in a zig-zag or weaving motion.
Walking the Cup TIG Welding Techniques
Source: https://www.youtube.com/watch?app=desktop&v=UVD89O9IhVw
Comparison-wise, walking the cup looks like moving the heavy drum across the shop. Instead of lifting and moving the drum, you roll it side to side to move it across the room.
While walking the cup seems pretty straightforward, this is quite a specialized TIG welding technique. It requires tremendous practice and skill, so we'll discuss its applications and challenges more.
Why Do You Walk The Cup?
TIG pipeline welding, especially on larger-diameter pipes, can be really tiring. Maintaining a consistent arc length, moving and dabbing the filler, and adjusting the travel angle to the pipe geometry can cause fatigue and frustration.
A solution to these issues is the walking cup technique. By resting the cup on the bevels of the pipe, you get arc stability and greater comfort. Resting the nozzle on the sides of the joint dramatically reduces fatigue and makes it easier to change the angles and accommodate the dynamics of welding. Additionally, you can rest the wire inside the joint, so there is no need for an extra hand while feeding.
If you provide an excellent part fit-up, resting the cup also yields consistent arc length through the joint. Consistency is crucial in achieving the highest-quality welds and positively affects the weld aesthetics. By walking the cup, you can create some of the most visually pleasing TIG welds.
When To Walk The Cup
Welders, most commonly TIG, walk the cup on various piping applications. You can use it in pipeline welding or within fillet welds, where you can rest the cup on the sides of the joint. This reduces the fatigue and improves the results. Walking the cup also works with most common pipeline metals, including carbon steel, stainless steel, or aluminum, but there are some limitations.
Walking the cup is most effective for pipes with an approximate diameter of 2". In these applications, walking the cup technique provides an excellent ratio between speed, quality, and aesthetics.
You can finish your project without too much hand fatigue and wasting time. Additionally, TIG walking the cup produces much prettier welds compared to traditional Stick welding. So, you should walk it whenever you want to produce the highest quality and prettiest welds.
Source: https://www.youtube.com/watch?app=desktop&v=UVD89O9IhVw
When Not To Walk The Cup
Although walking the cup TIG welding works on all materials, there are some limitations. When TIG welding aluminum pipes, the high heat of the cup can leave a trailed impression along the groove. Marks appear due to aluminum's lower melting point compared to steel or stainless steel. Additionally, burning the surface layer with a cup can create weak spots that are vulnerable to contamination.
Walking the cup may also be unsuitable for pipes with highly polished surfaces and machined parts. Once again, the cup can leave scratch marks on the grooves, affecting the overall weld aesthetics.
Many welders prefer the freehand technique for pipes smaller than 2". In the shorter runs, you can easily control the parameters through the weld by hand, and it's less likely that you'll need to rest the cup on it.
Additionally, welders dislike walking the cup on huge pipes. While it reduces fatigue on the longer runs, it can take a lot of time to fill the root. So TIG walking the cup can take time and effort in large-scale industrial applications.
How To Walk The Cup With TIG Welding
As noted, walking the cup is a pretty straightforward method, but it requires a lot of time and practice to get it right. That's why we'll discuss more on how to walk the cup and what you need for it, with some tips and practical advice that can make or break your next project.
To successfully walk the cup, you will need the proper gear, weld preparation, and the right technique. So, let's discuss this further.
Photo by @elwelderqueretano (TikTok)
Welding Equipment For Walking The Cup
Firstly, you will need the right equipment to walk the cup. That includes a power supply or TIG welder, welding torch, and filler rod.
The power supply, or TIG welder, typically uses a DC current rated at 200-250 amps. A simple machine with regular settings will do fine, but the more welding parameters you have, the better results you can get. Therefore, adjusting the pre-flow, post-flow, or using pulse can ensure proper tie-in and heat control when walking the cup.
The TIG welding torch should withstand the heat of an arc. In most cases, an air-cooled TIG torch rated at 200-250 amps will do just fine. Since root pass on smaller diameter pipes is not so extensive, you won't need a higher amperage than that. Keep in mind that walking the cup requires a lot of manual dexterity, so you can use the smaller torch with flex-head options.
TIG torch consumables, or more importantly, the cup, will play a crucial role. The nozzle should sit in the groove, and you should adjust the size based on the joint configuration and size.
TIG welding uses a filler rod during the walking of the cup, and the general rules state that it must be at least the same size as the root opening or one size larger. The key is to let the rod rest inside the joint without letting it fall through.
Walking The Cup TIG Welding Parameters
The more parameters you can set, the better results you can get when walking the cup. While you can produce decent welds with a simple welder, we recommend YesWelder TIG 200 AC/DC Pulse. This TIG welder will allow you to control the entire welding process and use a pulse. Here are some valuable parameters for walking the cup TIG.
TIG-200P-ACDC-PRO AC/DC Aluminum TIG Welder
- Amperage: Like regular welding, walking the cup requires amperage based on material thickness, inter-pass temperatures, and heat input requirements. While values can vary, 90 to 110 amps works well on most medium-thickness materials.
- Pre-flow: Adjusting the pre-flow will ensure higher cleanliness and provide reliable arc starts. Shielding the joint before welding makes sure it stays clean and provides a stable arc. This is crucial when welding a root pass with walking the cup technique.
- Post-flow: Letting shielding gas run for a few seconds after you complete the weld will prolong consumable life and protect the finished weld as it cools.
- Arc start: TIG arc start can make walking the cup much more effortless. Since the tungsten shouldn't touch the weld, it is best to use a TIG welder with a high-frequency start. You can use Lift TIG on thicker pipes where the risk of contamination is low, but high-frequency is a go-to method today.
- TIG Pulse: Pulsing between peak and background amperage can be helpful when walking the cup on heat-sensitive materials. Peak amperage will melt the pieces and filler rod, and background amperage will quicken the cooling and prevent heat buildup. Avoiding overheating is crucial when TIG welding a root pass since you can burn large holes in your root. Pulsing can also promote a good tie-in, which is helpful for many beginners who want to try to walk the cup.
Source: https://canaweld.com/benefits-pulsed-tig-welding-stainless-steel/
Consumable Sizes
Selecting the right size of consumables is crucial in achieving strong and satisfying results when TIG walking a cup. From the cup through the tungsten and filler rod, everything must match the bevel angle, root opening size, and thickness of the pipe or base metal.
TIG welding cups must comfortably sit inside the bevel or on the T-joint sides, so you'll need the correct size. The cups are sized by 1/16" of an inch, which is the inside diameter of a cup. For example, a size four cup is 4/16", a size 12 cup is 12/16", etc.
Generally, when walking the cup on root pass, welders prefer a number six (3/8 inch) cup. This nozzle can comfortably sit inside the groove without touching the weld, and it is a go-to choice, but the size can vary based on joint configuration and dimensions.
TIG welding is typically used for a root pass in the pipeline industry, as it can produce a solid foundation and high-quality results. Fill and cap passes can be time-consuming. Nonetheless, if the weld specification calls for TIG, you can also walk the cup. For hot and fill passes, welders recommend #7 cups, while you can do the cap pass with #8 cups.
TIG Rod And Tungsten
The size of the TIG rod should allow it to sit inside the joint. Since you are applying slight pressure to the rod, you don't want it to fall through. For example, you will need a 1/8-inch filler metal diameter for a 3/32-inch groove. The only exception is when back-feeding the filler rod. In that case, the rod is smaller than a root opening, and you feed it from the back of the pipe. However, this is not a typical technique when walking the cup TIG.
Although tungsten is a non-consumable part of the GTAW process, its composition, size, and length should match the other parameters. Welders most commonly use a 3/32-inch diameter, 2 percent thoriated tungsten.
Due to the health risks of thorium, thoriated tungsten is often replaced by lanthanted tungsten. The tungsten stickout should be as long as the inside diameter of the cup. For the #6 cup, the tungsten stickout should be 3/8 inch.
Keep in mind that we mentioned only the general recommendations. You might have to adjust everything according to your project, but you can use the explanations as a starting point.
Weld Preparation For Walking The Cup
Walking the cup and the entire GTAW welding is about consistency, and the best way to accomplish that is proper weld preparation. Weld preparation includes cleaning and beveling the pieces and achieving a good part fit-up, which is crucial in any pipeline welding preparation.
TIG is all about cleanliness, so make sure your parts and tungsten are contamination-free. You should bevel the pieces and leave the root opening according to weld specifications and pipe thickness.
This technique requires excellent alignment and part fit-up. Therefore, you must create an even gap throughout the joint. The best way to do that is to insert the rod the same size as the specified root opening size. Next, you will want to tack the pieces to keep them together.
Walking the cup requires four to six 1-inch-long tacks, depending on the size of the pipe. Tacking the pieces ensures that the pipe will stay in place and has an even gap across the joint. You can grind the tack to a feathered edge to provide a solid tie-in.
If you have a mismatch or highs-lows in pipe alignment, you will have to make adjustments. If there is a mismatch caused by pipe out-of-roundness, you will need to pull the weld puddle to the high side of the joint. Don't spend too much time on the low side, as it can cause excessive root reinforcement (or overwelding). You can create other defects, such as excessive weld penetration, cold lap, and improper tie-in.
TIG Welding Technique For Walking The Cup
Preparing to walk the cup with TIG welding is essential, but the proper technique matters most. Unfortunately, you'll have to practice and learn that on your own, but we will give you some tips to make the learning process easier.
First of all, you should know that seasoned welders distinguish between two walking-the-cup techniques. The first one is the actual walk-the-cup technique, while the other is more of a "wiggle" technique.
True Walking The Cup Vs Wiggle The Cup
In the true walk the cup, you are actually walking the cup on the weld that you are depositing. Your cup is resting directly onto the weld, and you should be using as little stickout and as little torch angle as you can get away with. The motion in the actual walk the cup is moving or rolling the barrel across the floor. As you roll the cup as you travel, you are keeping traction between the cup and the weld.
The wiggle-the-cup is an alternative technique that many turn to. In this case, you rest the cup on the bevels of the weld joint and wiggle the cup across it. This is a slight motion that allows you to wash in the edges and create even welds. With the wiggle technique, you can maintain a steeper angle and longer tungsten stickout—the tungsten extends beyond the edge of the cup.
Both techniques involve weaving beads, and you typically move uphill from the bottom (6 o'clock) to the top (12 o'clock) of the pipe. Opposing regular TIG welding, you should feed the filler metal at the leading edge of the weld puddle. Maintain slight pressure on the filler metal and ensure that it is tangent or at an angle to the pipe.
Walking the Cup On Root Pass And Other Passes
As we noted, most TIG welding walking the cup is performed on a root pass in the pipeline industry. To ensure the torch angle, travel speed, root opening, and filler metal feed are proper, you should keep an eye on a fluid dot in the center of the weld puddle.
This fluid dot on mild steel appears due to additives such as silicon, and welders refer to it as 'devi's eye.' Seeing the devil's eye is proof that your technique is proper and your welding parameters are correct for the specific pipe welding.
Things slightly change when you are walking the cup on a hot pass, fill pass, or cap pass. On the following hot or fill passes, you should use a larger cup since you have already filled the root. Now, instead of two-point contact with the edges of the weld, you have three-point contact. The puddle touches both edges, and a root passes as you move across the joint.
For the cap pass, an even larger cup (#8) provides adequate shielding gas coverage. During the cap pass, the torch should only make single-point contact. Pivoting carefully on the weld face will produce aesthetically pleasing and strong results.
Tips For Successful TIG Walking The Cup
Instead of a usual conclusion, we'll bring you the summed-up tips for successfully walking the cup for the end of our article. Here are some tips when walking the cup:
- Clean and align the edges of the pipes or fillet welds
- Get the TIG welder that allows you to set parameters such as pulsing, peak amperage, pre-flow or post-flow
- Use a large enough cup that can sit in the prepared bevel or weld
- The tungsten stickout shouldn't be larger than the diameter of the cup
- The TIG filler rod diameter shouldn't be smaller than the root opening.
- For true walk the cup, use as little stickout and as little torch angle as you can get away with
- Maintain a steeper angle and longer tungsten stickout for the "wiggle" technique.
- Move from the bottom to the top of the pipe (uphill)
- Feed the TIG rod at an angle to the pipe and into the leading edge of the puddle.
- Maintain slight pressure on the filler metal.
- Look for the devil's eye when walking the cup on root pass.
- Use even larger cups for fill and cap passes.
- Pull the weld puddle to the high side of the joint if you have a mismatch.
🧐TIG Welding Technique: Walking The Cup Explained FAQ
1. What Is Walking the Cup?
Walking the cup is a TIG welding technique used for grooved pipes and Tee joints. The cup (nozzle) of the GTAW torch rests on the pipe edges, while the welder moves it in a zig-zag or weaving motion, feeding the filler rod into the joint. This technique resembles rolling a heavy drum side to side rather than lifting it.
2. How to choose the right consumable sizes for Walking the Cup?
1. Cup Size: Select a cup that fits comfortably in the bevel or on the T-joint. Typically, use a #6 cup (3/8”) for root passes, #7 for hot and fill passes, and #8 for cap passes.
2. TIG Rod Size: Choose a rod that fits snugly in the joint, such as a 1/8-inch rod for a 3/32-inch groove.
3. Tungsten Size: Match the tungsten to the cup size. A common choice is a 3/32-inch, 2% lanthanated or thoriated tungsten, with the stickout matching the cup’s diameter (e.g., 3/8” for a #6 cup).
👏 You may be interested in the following:
- Right TIG Filler Rods For Different Metals
- Pulsed MIG Welding Tips And Techniques
- Underwater Welding Challenges And Prospects
Leave a comment