TIG Welding Arc Starting Methods - Scratch Start Vs Lift TIG Vs High Frequency
August 01, 2024TIG welding, while complex, is a rewarding welding method that produces high-quality results. The complexity lies in factors such as choosing the right tungsten, shielding gas, maintaining cleanliness, and mastering the technique. These challenges are what makes TIG welding a fascinating skill to learn for beginners.
Depending on your TIG welding machine, there are also several ways to start an arc. Three primary types are a scratch start, lift start, and high frequency.
Given that each method has its advantages and disadvantages, we will delve into the nuances of scratch start vs. lift TIG vs. high frequency. This comprehensive understanding will equip you to make an informed choice for your next welding project.
TIG Welding Aluminum
Photo by @vanthefabricator (TikTok)
What Is An Arc Start?
Arc welding methods, such as MIG welding, Stick welding, or TIG welding, which we are discussing today, use an electric arc to melt and fuse electrodes and pieces. The arc is formed once you close an electrical circuit between the electrode and grounded base metal.
Now, while this is a basic explanation, it's important to note that each arc welding method has a unique way of initiating an arc. In some instances, you may need to make contact with the base metal using your electrode to establish an arc (contact arc starting); other times, the machine detects the opposite side of the terminal and initiates an arc (non-contact starting method).
This understanding of arc-starting methods enhances your knowledge and proficiency in TIG welding. It all comes down to a specific welding method, but today, we'll focus more on TIG starts.
Source: https://www.codinter.com/en/tig-welding-a-complete-guide/
TIG Welding Arc Starting Methods
In TIG welding, there are three primary arc-starting methods:
- Scratch start,
- Lift TIG,
- High frequency.
If you are an absolute beginner browsing a TIG welder market, you probably came across one of these terms, but you have yet to learn what they mean. Fear not, as we will thoroughly explain each, including its advantages, drawbacks, and applications.
TIG Welding Process
Scratch Start In TIG Welding
The scratch start is one of the oldest arc-starting methods, and it was designed similarly to stick welding. As you can assume from the title, you will have to scratch the base metal with your electrode to establish the arc. Essentially, the entire procedure is pretty similar to lightning a match.
To start an arc with a scratch start, you first push the trigger to start the current and shielding gas. Next, you will have to flick the base metal with your electrode like you would do with a match until the arc appears. As soon as the arc starts, you have to lift the torch to prevent the tungsten from sticking and fusing with base metal. However, you shouldn't lift the torch too high, as you can extinguish the arc.
Pros & Cons Of Scratch Start TIG
You don't have to be an expert to notice that this type of TIG start has lots of drawbacks. First of all, it can be highly challenging to master the movement and get the reliable arc starts. But that is only the tip of the iceberg.
Scratching the base metal with your tungsten can contaminate either the tungsten or the base metal. As you scratch the surface, small parts of tungsten can get into the joint, creating tungsten inclusions. These are defects where the tungsten fused into the weld has properties different from those of the base metal, creating weak spots in the weld.
Source: https://www.youtube.com/watch?app=desktop&v=0h5yw-qrl9c
Additionally, small pieces of base metal can contaminate your tungsten electrode. Contamination can create a highly inconsistent arc, so you will have to re-grind your tungsten.
Due to many drawbacks, both manufacturers and welders are switching to Lift TIG and high-frequency starts. That's why TIG welders with a scratch start are scarce today and typically some of the cheapest on the market.
Lift TIG
Lift TIG was invented as an alternative to scratch start as it provides minimal contact between the tungsten and base metal. Although contact is minimal, this is still considered a contact-starting TIG method.
To initiate a lift TIG arc start, you place your tungsten on top of the base metal and start the current and shielding gas. As soon as you start the current, you lift the electrode, ergo the name Lift TIG. As you lift the tungsten, the machine senses the gap. You'll hear a "pop" sound, and the arc will jump between the electrode and base metal. Similar to scratch start, you shouldn't lift the torch too high to extinguish the arc.
Pros & Cons Of Lift TIG Start
Lift TIG produces the low voltage before the actual arc starts, so the risk of the electrode sticking to the base metal is minimal. You are not violently scratching or touching the base metal with your electrode, so the dangers of inclusions and defects are significantly lower. This minimal contact also makes a Lift TIG much cleaner method than scratch start, but it is less clean than high frequency.
Although much better than the scratch start, Lift TIG is still considered a contact starting method, so it has some drawbacks. Even if the starting voltage is low, if you over-tune the starting amperage, tungsten can stick to the base metal, again creating tungsten inclusions and damaging your electrode.
High-frequency TIG Start
High frequency is the most advanced TIG arc-starting method that provides maximum cleanliness. HF is a non-contact arc start that uses a high-voltage/low-current arc, which is quite the opposite of processes such as Stick welding.
Due to high voltage, the arc can jump between the distance, meaning you don't have to touch the base metal with the electrode. The low current makes this arc shock-free so that you can operate safely.
As the high voltage jumps from the electrode to the base metal, it ionizes the air, creating a fourth state of matter - plasma. The plasma has extremely low electrical resistance, which means even the low current arc can get through and initiate the main arc. Once the main arc is initiated, it maintains its plasma to stay lit.
So, to initiate the high-frequency TIG start, all you have to do is put your electrode close to the weld joint and start the current and shielding gas. The arc will automatically jump, and you can start welding.
Advantages of High Frequency
Due to its nature, TIG high-frequency arc start is a safe, reliable, and very clean arc starting method. Since you are not touching the base metal, aside from operator errors, there is no risk of contaminating either the base metal or tungsten electrode.
This cleanliness makes high-frequency an essential arc-starting method when TIG welding aluminum or other delicate metals that are prone to defects and contamination. High frequency also helps to stabilize the arc during welding.
Arc stabilization is essential during AC TIG welding. As the current oscillates from the positive to the negative part of the cycle, it passes over the 0 voltage border, which would typically extinguish the arc. However, ionized air has such low electrical resistance, so the voltage never drops so low, and the arc continues to run.
High-frequency is used to be a part of the state-of-the-art TIG welders, as it provides solutions to nearly all issues of scratch start and lift TIG. However, technological advancements have made this technology cheaper, so you don't have to spend a fortune, and you can find it in our YesWelder TIG200P AC/DC TIG welder.
Drawbacks of High-Frequency Start
There are very few drawbacks to high-frequency start in TIG welding. Firstly, high frequency creates a low-current, soft arc, which is not always suitable for thick metals. But, if we look at the bigger picture, welders rarely choose TIG welding in general when dealing with thicker stock, so this is not such a big issue.
The most significant drawback of HF start is the "electrical noise" that it produces. The arc can interfere with frequency-sensitive devices such as CNC tables, radio towers, telephones, or airports, so you should be careful when and how do you use high-frequency start.
Source: https://www.youtube.com/watch?v=JvjXOm3H2s8&t=128s
Overview of Scratch Vs Lift Vs High-Frequency Arc Starting Methods
| Scratch Start | Lift TIG | High Frequency | |
| Start Difficulty | It takes time to master | Moderate | Easy arc starting method |
| Contact With Base Metal | High contact | Minimal contact | No contact |
| Contamination | Potentially high risk | Minimal risk | No risk |
| Aluminum Welding | Not recommended | Only in specific applications | Go-to method |
| Equipment Cost | Very low | Moderate | It used to be high, now it is moderate |
Scratch Start Vs Lift TIG
Both scratch start and lift TIG are considered contact TIG starting methods, but there are quite a few differences between them. While scratch start actually includes scratching the base metal to start an arc, Lift only requires a slight contact at the beginning. Lack of contact makes Lift TIG a much cleaner TIG starting method.
Lift TIG is considered much more beginner-friendly than the scratch start. The skill required to initiate the arc is minimal, and you can master it in no time. Meanwhile, beginners can often struggle with a scratch start until they get everything right.
The only time we would recommend scratch-starting the TIG welder over the one with lift TIG or HF is if you are on a very tight budget. However, lift TIG is so much cheaper today, and our TIG205P PRO DC TIG welder is valid proof.
YesWelder TIG-205P-PRO Pulse TIG Welder
Lift TIG Vs High-frequency Start
While the results on scratch versus Lift are pretty straightforward, they are closer when comparing lift tig and high-frequency arc starting methods.
If we start with cleanliness, both HF and Lift are considered as clean arc starting methods. However, high-frequency is a non-contact method, while Lift still has that short period where you have to touch the base metal. Putting too high a starting amp with Lift can cause defects, while you don't have to worry about that with high-frequency.
Both Lift and High-frequency are considered easy to perform and master, but HF, once again, takes an edge. As a new welder, you might hold the torch too high and extinguish the arc. However, HF is more forgiving for initial arc initiations.
High frequency thrives once you switch to alternating current (AC). The arc stabilization caused by ionized air around the arc allows you to maintain a stable and reliable arc across the weld. Stable AC arc makes High-frequency a must-have if you are planning on TIG welding aluminum.
As we noted, things are changing when it comes to equipment costs. In the past, HF was featured in professional and industry-grade, expensive welders, which made Lift TIG a much more common choice for DIY and home use. However, with YesWelder YWT-200 DC Pulse TIG welder , you don't have to spend a fortune on a machine with high frequency.
YesWelder YWT-200 DC Pulse TIG welder
Due to various advantages over the other arc starting methods, many seasoned welders recommend TIG machines with High-frequency start. We recommend the Lift TIG of HF only if you are welding near frequency-sensitive devices or if you only occasionally TIG weld steel around the hose.
Scratch Start Vs High Frequency
Comparing scratch start vs. high frequency is not a fair competition since it is like comparing old, outdated, hard-to-use, less efficient technology to the new one, which is convenient, easy to use, and with very few flaws. If you ever have to choose between a TIG welder with high frequency and one with a scratch start, you should go with, without a doubt, the one with an HF start.
Knowing how much better HF is than Lift TIG and then Lift TG is better than the Scratch start should be a very logical explanation of which one you should choose. Once again, the only reason to use scratch over HF is the "electrical noise" or if you are on a very tight budget, but with the latest trends, finding a machine with scratch can be challenging, so we suggest you go with reliable YesWelder TIG welders, that at least offer lift TIG.
Final Thoughts
There are several ways you can start an arc with your TIG welder, and the technological solutions from scratch, over Lift to High-frequency, are notably better. The Scratch start was the foundation of good old TIG welders, but it was replaced by Lift TIG, which overcomes many drawbacks and comes at a reasonable price.
However, High-frequency overcomes most drawbacks of the other arc starting methods, so it is a logical choice. This state-of-the-art technology was reserved for professional-grade welders in the past, but we at YesWelder brought it to our welders for beginners and hobby users.
🧐TIG Welding Arc Starting Methods - Scratch Start Vs Lift TIG Vs High Frequency FAQ
1. What are the primary arc-starting methods for TIG welding?
In TIG welding, there are three primary arc-starting methods: Scratch Start, Lift TIG, and High Frequency start.
2. Should I choose Lift TIG or HF TIG?
HF TIG is generally the better choice because:
• It’s cleaner and non-contact.
• It’s easier for beginners and more forgiving.
• It excels with AC, making it ideal for welding aluminum.
Lift TIG is a good alternative if budget or availability are concerns, but it requires more careful handling to avoid defects.
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