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Sumark Industrial Co.,Ltd.
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Knowledge
Complete beginners to TIG should begin on 2mm or 3mm steel. The weld pool is larger and easier to control on thicker steel which makes it easier to develop technique - trying to learn on thinner material will be more frustrating. We've used 2mm steel for this tutorial. The welder was set to 50 amps, and the tungsten and filler rod were both 1.6mm.
*****Find a Steady Position
*****Find a Steady Position
When TIG welding you need to be able to control the distance between the tungsten and the work to within about 1mm. This is only possible with a good welding position. In the photos the welder has used a few tricks:
- Just to confuse you we've photographed a left handed welder. If you are right handed hold the torch in your right hand.
- The welder is sitting down and working on a bench. His upper body weight is not supported by the bench - the bench is only used for positioning.
- In the photo a flexible torch head (very handy) is being used to maintain the angle of the torch with the hand resting lightly on the bench. The hand would need to rest on a piece of wood for the correct angle with a standard torch.
- The torch lead is wrapped around his arm. This takes the weight of the lead away from the torch and reduces the chance of the lead snagging as the weld progresses.
- The head is positioned to the side for a good view of the weld pool. It is very common for beginners to hide the weld behind the gas shroud.
- The lighting is from the side as well as overhead - it allows the welder to see the tungsten position before starting the weld.
- The torch would move in the direction of the red arrow in the photograph (that one isn't really a trick but is worth a mention while the photo is there).
Relaxed muscles will aid control of the torch - try not to TIG weld directly after hammering or other physical activity, and ensure the workshop is at a comfortable temperature.
The red dot in the photograph just below the torch shows the area the welder will be looking at while welding. It's a tiny area, so for a good view his eyes need to be close to the weld. It's very common for people to discover they need glasses when they first take up TIG welding.
*****Learning to TIG Weld
*****Arc Length
*****Learning to TIG Weld
Begin by starting the arc on steel. Get a feel of the arc and the weld puddle.
Next try welding on the surface of some sheet without using filler rod. This will help you get a feel for how the puddle moves, and practice in maintaining a tight arc length. Finally move on to adding filler wire as in the video below.
We've used 1.6mm filler rod, but it would have been much easier to feed 1.0mm filler rod into the pool.
*****Arc Length
Arc length controls the amount of heat in the weld. TIG is a constant current process (the amps you set on the machine are the amps you get), but increasing the arc length will increase the voltage which in turn puts more heat into the weld.
Beginners will tend to have their arc length too long for fear of contaminating the tungsten. It should be maintained at between 1 and 1.5 times the diameter of the tungsten (that's between 1.6mm and 2.4mm arc length for the 1.6mm tungsten we are using).
Excessive arc length will make the arc difficult to control, and it will also make the tungsten very hot so if you do touch down into the weld pool the tungsten will suck up a fair bit of steel. That's what happened to the tungstens in the photo and it's a major frustration for beginners. With a tight arc the tungsten stays cool and touching down hardly even takes the point off the tungsten.
*****Size and Speed
*****Struggling
*****Size and Speed
If your bead penetrates through the rear of the steel before you get the hang of laying a nice bead it is likely that your travel speed is too slow.
The travel speed can be judged by the width of the heat affected zone around the weld (the discoloured part). In the photograph it is quite narrow, maybe 15mm edge to edge.
If the weld had been done at lower amps and a slower travel speed to compensate the heat affected zone would have been much wider. A slow travel speed actually puts more heat into the weld as heat is conducted away from the weld pool before the weld pool is established.
*****Struggling
You did start off on 2 or 3mm steel didn't you? It really is a lot easier than the thin stuff.
The two welds in the photo on the right were made by a beginner TIG welder. In the first photo the welder was struggling to control the weld pool, and was having trouble adding the filler rod.
The second weld was made immediately afterwards with no further training. The only difference is the thickness of the steel (and the amps adjusted to suit). The increased thickness means the weld pool is larger and easier to control, which makes it much easier to add the filler rod.
The plate in the second photo hasn't been prepared properly - the steel needs to be completely shiny and free of rust or mill scale else the weld will spit steel back at the tungsten and contaminate it as soon as you start the weld.
The ease of welding thicker material makes it easier to understand and develop the technique. Also it provides a big confidence boost. Once you have the technique it is easily transferred to thinner material.
