Welcome to Tig welding tips!
Before we start, I’d like to give you a little background on my welding experience. I have been welding for 30 years, 20 of which were spent as a union pipefitter on various types of steel and alloys ranging from stainless to exotic metals such as inconel and titanium. As of this post, I am self employed, and most of my work is primarily on sanitary stainless applications, such as CIP Systems , modification of food service equipment, and a former instructor at Illinois Welding School in Romeoville, Illinois…
We’ll start with the basic concept of what the TIG welding process is. (GTAW), or Gas Tungsten Arc Welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the arc necessary to weld. The weld area is protected from
tig welding illustration
contamination by a shielding gas (usually an inert gas such as argon), and a filler metal is added to the molten material created by the arc, though some welding processes do not require the introduction of a filler material. This process is known as more of a “fuse” welding technique, and is commonly used in edge, corner, and butt joints, creating a smooth, easily finished weld .
Of all the different types of welding processes, TIG welding is considered the most difficult to master because of the required use of both hands in coordinating the weld puddle while introducing the filler material to the weld surface. This does require some skill, but can be mastered with practice and a little patience!
Welders will develop a technique of alternating between moving the torch forward (to advance the weld pool) and adding filler metal. The filler rod is withdrawn from the weld pool each time the electrode advances, but it is never removed from the gas shield to prevent oxidation of its surface and contamination of the weld. This “rhythmic” action is the skill that takes the most time to learn, and is best accomplished by counting to yourself to establish a consistent and uniform weld bead.
One of the fastest methods of learning to control the TIG torch, and a method used to produce consistent , high quality welds is a technique called “Walking the Cup”. The following video will illustrate this technique.
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We will do an extensive section on the TIG technique known as “Walking the Cup”, which is mostly used for V Groove welds in plate and pipe. The concept and advantage of walking the cup are obvious as consistency and quality of weld come into play. The rhythmic motion of the torch by the operator takes a little practice at first, but after a short amount of time the weld can be just as easily made with the opposite hand, making this method very versatile when welding out of position.
The following video gives you a pretty good idea of the process involved, and allows you to see the consistency of the weld.
The downside to this method is that it cannot be used for every weld job, and learning to free-hand TIG weld will still be the most important skill you will learn… see more on walking the cup below!
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There is a bit more info on the Walking the Cup technique. This process seems to be picked up fairly quickly by my students at the Illinois welding school were I currently instruct. To practice the process it is best to start on a flat piece of plate… 3/8 x 4. If using hot rolled steel, just be sure the surface is cleaned prior to welding. ie, scaling should be ground or flap wheeled off. Cup size shouldn’t matter at this point. The tungsten should be adjusted to a stick out distance of between 1/4 to 1/2″.
You physical positioning should be comfortable and the torch head should be unobstructed to allow for the forward movement of the torch. Placing the cup on the plate at about a 30 degree angle will allow the torch to walk forward as your hand movement resembles a figure “8″ motion. Striking the arc at this point just involves tipping the torch head forward enough to establish the arc.
Practice a bit on the movement beforehand to learn the motion necessary to achieve the proper travel forward. The pattern should be fairly tight. Don’t force the torch forward! It only requires a very light grip on the torch and this figure “8″ motion t0 achieve the desired results.
This technique should be practiced without filler metal to begin with. The amp setting for the 3/8 plate will be around 110 to 114 amps using a 3/32 2% thoriated tugsten. You need to establish the puddle and try to achieve and maintain a bead width of around 3/8″ inch. Adjust the amps accordingly. OK… should be fairly easy from here!
Adding Filler Metal
Once you feel comfortable with the technique it’s time to add filler wire to the weld puddle. The first thing is to establish the weld puddle BEFORE adding the filler wire. Note: You may require adjusting the amps up just a little to take into consideration the addition of the filler metal. Hold the filler at a bit of an angle to the plate, and if the heat is set right, you really won’t have to move the filler once you get started. Walking the cup does take a little practice, but once you get the hang of it, you will get a very nice consistent weld with the bead looking like it has been laced! I’ll be adding some video for this technique soon!
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Sep 09
11
Getting started…DC welding machines
There are basically 2 types of welding machines. The DC welder and the AC welder. For the sake of what we will be concentrating on in this article, the DC welding machine is the most common of the 2 types. When TIG welding, straight polarity (DCEN) is used. When setting up the machine for TIG the electrode or torch should be connected to the negative terminal of the welder. This will result in a cooler weld temperature at the material to be welded.
Another option that is very helpful, although not necessary is a foot pedal remote amperage control. This foot pedal not only controls the amperage from zero to a preselected high amperage, but also activates the High Frequency arc start and gas flow. If you happen to have an older DC machine that was designed primarily for stick welding, you do not have the remote options, High Frequency start, or gas control. However, if this is all you have, this machine will work fine. Years ago, we used old DC generator type machines to TIG weld without any problems. The disadvantage was having to manually turn on the gas flow from the torch by means of a gas control knob, and scratch starting the arc which meant a highly likelihood of tungsten contamination in critical X-ray quality welds. This may not pose a real problem for simple welding applications but if there is a concern, a scratch plate to start the arc can be used.
miller inverter welder
With the advent of new technologies, the inverter type welder is an excellent choice because of their light weight, (40lbs or less!) portability, and dual voltage (115v or 220v). They all feature remote control, HF (high frequency) arc start, and shielding gas control which includes post flow gas timer control. Since I’m not in the business of selling welding machines, I won’t go through the list of impressive features on this Miller unit shown here. However, here is the link to read more about it @ MillerWelding Products
This unit is one of the commonly seen “Made somewhere over there” units that claim 3 in 1 capabilities…TIG, Stick, and Plasma cutting. A friend of mine recently purchased this model and asked me to evaluate it’s performance. Well, I don’t know if I would carry this machine to a Union job site, but to my surprise it worked remarkably well for a under $500.00 machine! Plugged into a standard wall outlet, the TIG process, along with the remote function and post gas control did an impressive job. The plasma cutting was equally impressive, and at 35lbs, very portable…so for the cost, this may be the way to go for the budget minded…
- The 100K Welding Course
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