The material you are welding isn't the only metal that can contain contaminants; your fill
During use, some electrode blends naturally form a balled tip. Others do not and require a bit of prep work. The electrodes that do not form a balled tip (cerium blends and some others) should be ground to a point in order to provide a more concentrated and controllable arc. Using a pointed tip is also helpful when welding thinner materials (which is common in race car fabrication). You can do this with a regular bench grinder, but a few precautions should be taken. First, tungsten is much harder than any grinding wheel material. Instead of grinding the material down, it actually chips it away. This makes it difficult to get a smooth surface from grinding. If the electrode is held perpendicular to the rotation of the wheel, the grinder will create concentric ridges as the tungsten angles into a point. These ridges create exit points for the arc in several places along the taper, resulting in a wandering arc.
Instead, the tungsten electrode should be ground so that the marks run lengthwise with the point (hold the electrode so that it points at the wheel instead of across it). Now any ridges run down the length of the angle and to the point. Instead of a wandering arc, it remains concentrated between the point of the electrode and the material.
Even though the electrode doesn't melt, you may need to prepare your points fairly often. Anytime you touch the electrode to the metal while a current is running through it, it pollutes the electrode. When this happens, you may need to knock off the contaminated tip and regrind it. Also, because it is very important to keep foreign materials away from and off the electrode, maintain a special grinding wheel that is used only for grinding your electrodes.
The Next Step In Technology
One of the big drawbacks in TIG welding has always been the size of the units. New, inverter-based TIG welders are cutting the size of the units considerably. Miller Electric calls its machines the Dynasty Series, and welders that used to be the size of cabinets are now the size of a big suitcase. In fact, it is now possible to use Miller's 200-amp Dynasty TIG welder as a portable unit and carry it with you to the track on your hauler. In addition to being significantly smaller, inverter welders use 30 percent less energy than the previous generation of TIG welders, so once you get to the track you can power the unit with a gas-powered generator.