Since the electrode used by a TIG welding machine is not a consumable filler metal wire, it needs much different treatment than that used in MIG welding.The electrode in tig welding is continuously fed into the welding pool, melting in the electrical arc that it is generating, and so your main concerns are to ensure that there is enough wire and that it continues to move properly through the rollers to be delivered to the welding site.
The tungsten electrode of a TIG welding machine is not consumed as it is used, however, and filler metal is supplied by separate metal rods held in the welder’s gloved hand. Therefore,the shape and condition of the electrode are much more important in TIG welding, since the electrode remains the same throughout the whole welding project.
You need to ensure that the tip of your tungsten electrode is the correct shape. It needs to be tapered, but have a flat tip. This causes the electric arc to project neatly from the end of the electrode, rather than squirting out at a shifting, unpredictable angle. In order to achieve the right tip shape, you will need to grind the tungsten electrode down with a grinding wheel. There is a correct and an incorrect way to do this, which you should learn so you can use the former and avoid the latter.
Grinding a tungsten electrode
The business end of your TIG electrode needs to taper in much the same way as a pencil, but the grinding needs to be carried out with nearly scientific precision. The grinding wheel is used with the electrode applied so that the wheel’s rotation is in line with the length of the electrode. This will produce an even point with a flat tip, which is exactly what you need.
The grinding wheel should be either completely new,or one which has been used only to grind tungsten in the past, and ought to have a 200 grit surface.To determine how long you should make the tapered section at the electrode’s tip, measure the electrode’s diameter and multiply this by 2.5.For instance,if the electrode is 1/4” in diameter,the tapered tip should be 5/8” long. Be sure to leave a flat end on the electrode – do not taper it to a sharp point.
This is, of course,why you should avoid grinding the electrode tip with the electrode at an angle to the grinding wheel. This method will produce a sharp,pencil-like tip that is completely undesirable, since it will lead to an unstable welding arc that projects in an unpredictable direction and may even wander from place to place.
Aluminum welding with a TIG machine often makes a sphere accumulate slowly on the tungsten tip. Grinding a fresh tip becomes necessary when this sphere reaches the same diameter as the electrode it is growing on.This makes welding aluminum a stop-and-start affair, but leaving the sphere in place will eventually degrade the welder’s