Welding and its methods are far more complicated and intense than most non-welders realize, which is why machinery such as the lift TIG welder needs explanation. The two most common welding technologies and processes used in U.S. factories are metal inert gas (MIG) and tungsten inert gas (TIG) welding. Both MIG and TIG processes utilize electrical arcs to produce heat and therefore join metallic material and/or objects. TIG is a newer form of welding, and many remain unfamiliar with it.
So how is the lift TIG welder explained? A lift TIG welder is a machine that utilizes the TIG welding process with a lift start to the arc. This process involves a non-consumable tungsten electrode that runs a current through the metals to be joined, and is started by a light, smooth move of the torch that touches the tungsten to the metal—called a lift start. There are many benefits to TIG welding and a lift start as well.
Arc welding processes vary greatly, and the success of any welding project is based on choosing the right method in addition to developing excellent welding skills. Therefore, it’s important to understand welding methods and arc starts, such as the lift TIG welder, in addition to its benefits and potential limitations. This way, welders will be able to properly, sufficiently, and successfully make their welds.
Tungsten inert gas (TIG) welding, also known as gas tungsten arc welding (GTAW), is an arc welding process that uses a tungsten electrode which is non-consumable to produce the weld. The weld area and electrode are protected from oxidation and other contamination by an inert shielding gas such as argon or helium. In addition, a filler metal is also used in most instances.
TIG welding is a manual welding process primarily used for critical weld joints or where precise, small welds are required. It’s also used for welding thin sections of metals that are not common steel, such as stainless steel and aluminum, magnesium, or copper alloys. The constant-current welding power supply produces electrical energy that is conducted across the arc through a column of highly ionized gas and metal vapors.
Tungsten is a hard yet brittle, slightly radioactive metal. Compared to other metals, it has limited uses. However, in TIG welding, tungsten is made into a non-consumable electrode. This electrode is used to create the welding arc.
TIG welding requires the welder to use both hands, one to hold the TIG torch that produces the arc and the other to add the filler metal to the weld joint. This unique welding process makes TIG welding difficult to learn, but it’s considered a versatile and high-quality welding method.
There are many benefits to TIG welding, including:
- Greater control for the operator over the weld
- Allows for stronger, better, and more precise welds
- Versatility in welding alternate materials
However, there are drawbacks to TIG welding as well, including:
- More complex process than other welds
- Can be difficult for welders to learn and master
- Slower than most other welding techniques
The most common power used in the TIG process for welding is direct current (DC) and alternating current (AC) is used when welding aluminum.
How TIG Welding Works
TIG welding requires three elements: heat, shielding, and filler metal.
- The heat is produced by the electricity passing through the tungsten electrode by creating an arc to the metal.
- The shielding is produced from a compressed bottle of gas that flows to the weld area to protect it from the air.
- The filler metal is a wire dipped by hand into the arc for melting.
A welder will turn on gas flow, often located through a valve on the TIG torch. This flow of gas protects the weld area from the air. Then, the welder holds the torch over the weld joint close enough that the torch doesn’t touch the metal. The welder presses a foot pedal and the tungsten electrode on the torch begins an arc.
Once this arc is started, the two pieces of metal to be welded start to melt and create a puddle. The welder then dips a welding wire into the arc to fill the joint and create a single metal piece.
The tungsten metal properties allow an arc to maintain a temperature up to 11,000 degrees Fahrenheit. Due to its high melting point and good electrical conductivity, the tungsten electrode does not burn.
Three Ways to Start a TIG Arc
There are three basic ways to start a TIG arc. Arc welding is used to join metal to other metal through using electricity that creates enough heat to melt metal. When the melted metal cools, the result is binding between them. Arc welding utilizes a power supply to create an electric arc between a metal electrode and base material in order to melt the metals at the arc’s point of contact. TIG arcs are started in three ways: scratch, lift, and high frequency.
The scratch start for TIG welding is an older method of starting an arc. It is similar to striking a match in that it involves “flicking” near molten tungsten across the metal until an arc starts. This start works just fine and allows nearly any DC (direct current) stick welder to become a TIG welder with little effort.
However, scratch start for arcs does have some drawbacks. The tungsten becomes hot almost instantly as the arc is struck. In addition, small pieces of the tungsten often break off and become stuck in the weld. This can result in subsequent structural problems and contamination of the weld material.
Overall, scratch start is an effective way to begin TIG welding and is commonly used for general welding work. However, this arc start is considered fairly rudimentary, less clean, and less pure when it comes to welding than other arc starts such as lift and high frequency starts.
Lift start is often confused with scratch start, but it is distinctly different. With the lift start, the welder brings the tungsten down quickly and lightly in contact with the metal and then quickly lifts up to draw the arc. This action makes it look like a scratch start, but instead it’s a cleaner process with less contact with the metal.
To operate a lift start TIG welder, the operator uses a trigger or foot pedal, but there is no arc jump between the tip of the tungsten and the metal. Instead, the operator puts the cup down on the metal, clicks the trigger, or pushes down on the foot pedal. The operator then rolls the torch upright so that the tungsten touches the metal as the torch is lifted up in a slight, smooth move.
With a lift start, the open-circuit voltage (OCV) of the welder reduces to a low voltage output when the unit senses a continuity with the work piece. As the tungsten is lifted and leaves the surface, the unit increases voltage output. Unlike scratch start, this generates little contamination and preserves the point on the tungsten. It’s not completely clean and the tungsten is still somewhat subject to contamination.
Lift start is a better option for TIG welding than using scratch to start an arc. This is especially true for steel and stainless steel. However, it’s not a good option for aluminum due to that metal’s reaction with tungsten.
High Frequency Start
The use of high frequency start in TIG welding is considered by many operators to be the most popular and best option due to its cleanliness and efficacy. This start generates a high frequency arc that ionizes the air and bridges the gap between the tungsten point and work piece. As a result, this is a touchless method which causes almost no contamination unless the tungsten is over-sharpened or the amperage is turned up too much to start.
High frequency start is nearly the only choice for TIG welding with aluminum since there is no contact between the tungsten electrode and aluminum metal. Yet otherwise it’s not a necessary arc start for TIG welding. However, it is a good option for TIG welders who can afford more expensive equipment and wish to have the latest technology when it comes to arc starts.
Lift TIG Welder Explained
Lift TIG starts are considered a positive development as an alternative to scratch starts or high frequency arc starts. Lift start provides consistent, positive arc starts for welding with a DC output. There are two primary reasons for the development of lift TIG:
- High frequency current interferes with electronics, including all forms of computers and some machinery.
- Scratch start technique in which the operator scratches the tip of the tungsten on a weld piece like a match struck against a box, poses a high risk of contaminating the weld with tungsten particles. In this case, if the application were critical, the arc start would need to be ground out and rewelded.
As a result, a lift TIG welder eliminates any issues associated with high frequency starts. In addition, if performed properly, lift start also almost entirely eliminates the risk of tungsten inclusion and, therefore contamination of the weld.
Novice operators may experience initial frustration with a lift TIG welder unit, primarily because they are more familiar with the scratch start technique. For the lift start, it’s critical that the operator just lightly touch the tungsten to the work piece rather than scratching it. In addition, the tungsten electrode must be held to the work piece briefly before the operator lifts the TIG torch.
It’s important to note that lift TIG is not acceptable for welding procedures that specify a non-contact arc starting method. This may be the case with pressure vessels and process piping or other welding systems that require high frequency arc starts.
However, incorporating high frequency components can add hundreds of dollars to the cost of a power source. Not all welders wish to pay for this functionality that they may not use. Therefore, most weld equipment manufacturers offer only lift TIG welder power sources or power sources with both lift and high frequency TIG arc starts.
Benefits to Lift TIG Welder
There are many benefits to using a lift TIG welder, including the weld seam quality, use near computers or electronics, and lower cost:
- Weld Seam Quality: Using a lift TIG welder allows for high weld seam quality in the purity of the weld and surface finish. These weld seams are compact and thin. Other advantages of this procedure include full penetration and a clean process. This is especially effective when it comes to welding tubes, or other critical and demanding projects in industries such as semi-conductor, pharmaceutical, food, dairy, and aerospace.
- Welding near computers or electronics: Many TIG welders use high frequency start. However, a lift start is much more effective when performing welding on a car or near computers and electronics. This is due to the fact that high frequency start can affect computers and electronics in a negative manner, even today’s vehicle computers.
- Cost: It’s often advisable for welders to purchase machines that offer both high frequency and lift start. This allows for versatility in welding that other machines do not. However, there is a cost difference. A machine with high frequency will cost more than one with just lift start. Therefore, lift TIG welders are more cost-effective than high frequency machines.
Lift TIG arc start is a reasonable and effective compromise between the rudimentary scratch start arc process and the costly high frequency start arc process. Though lift TIG welders have some limitations where non-contact arc starting methods are required, overall, the lift start method is clean, affordable, and reliable. It can also be used near computer and electronic equipment, whereas high frequency starts may interfere with such entities.
Equipment Required for Lift TIG Welder
There are several elements of equipment required for TIG welding and a lift start operation. This equipment includes:
- a welding torch
- non-consumable tungsten electrode
- constant-current welding power supply
- shielding gas source
TIG welding torches can be automatically or manually operated. They are similar in construction, yet the manual torch features a handle. In addition, the “head angle” can be varied on some manual torches to the preference of the operator.
These metal torches transmit current and heat effectively, and the tungsten electrode is held firmly in the center of the torch. Ports that surround the electrode provide a flow of shielding gas. The torch features heat-resistant and insulating plastics that cover the metal components to protect the welder from heat and electricity.
The TIG electrode is made of tungsten or an alloy due to its highest melting temperature among pure metals. Because of this, the electrode is not consumed during welding, although some burn off or erosion can take place.
TIG welding utilizes a constant current power source so that the current and heat remains relatively constant even if the arc distance or voltage change. This is especially important in manual TIG welding since the operator must hold the torch and maintain arc stability. A constant current power supply prevents heat variations which can cause welding to become more difficult.
TIG welding power sources feature either lift arc start capabilities or both lift and high frequency arc start capabilities.
Shielding gases are required in TIG welding in order to protect the welding area from gases in the atmosphere, such as nitrogen and oxygen. These gases can cause fusion defects and embrittle the weld material if they come in contact with the electrode, arc, or welding metal. The shielding gas also transfers heat from the tungsten electrode to the metal and helps start and maintain a stable arc.
The composition of shielding gas depends on several factors, such as the material being welded, joint design, and the intended look of the final weld appearance.
Manual TIG Welding Applications and Characteristics
TIG welding has many field applications, including assembly and production lines and on-site repairs. Introduced and heavily utilized in the 1940s, the TIG process is known for high quality standards and reliable welds. With this type of welding, there is almost no welding smoke or residue, particularly if a lift or high frequency start is used.
Most metals can be welded with TIG procedures, including stainless steel, titanium, magnesium, and copper. The process is stable, produces superior quality, and welding defects are generally rare. However, TIG welding equipment requires a higher investment than other types of welding in most cases. In addition, the process can take longer, and the required energy for the weld may be slightly higher. TIG welding can also call for a slightly cleaner environment.
Welding, in any form, is a highly developed skill. Manual TIG welding requires even more skill and expertise than other methods and processes. It’s important for welders who wish to undertake TIG welding to understand all aspects of the process, as well as the merits, drawbacks, and fundamental explanation of elements such as the lift TIG welder.