MIG welding using flux-core wire works as well as stick welding on dirty or rusty material. In addition, self-shielding gasless wire can be used for welding outdoors. The use of self-shielding wire increases portability as there is no gas cylinder to haul around. MIG welding using flux-core wire offers deeper penetration when welding thick sections and a high rate of metal deposition allows the job to be completed faster.
The third type of welding that we are concerned with is TIG or gas tungsten arc welding. TIG welding process uses a non-consumable tungsten electrode and a shielding gas that protects the welding area from contamination. The arc comes off the point of the tungsten to melt the base metal while the operator manually adds filler wire in a technique similar to brazing. TIG welding is the type of welding that offers the most flexibility. Unlike MIG or stick, TIG welding lets an individual operator control heat input while working using a remote foot pedal or fingertip control. Hence, welding on thin materials is more easily accomplished and with less distortion.
The TIG process welds all metals with just a single gas, usually argon. TIG welding provides the highest quality detail work, and very aesthetic weld beads can be created. TIG welding also produces the least amount of sparks or spatter. Both flux-core and stick welding use an electrode with positive polarity and the work is grounded. Both use a constant current design. In gas-protected MIG welding and in TIG welding the electrode has negative polarity. As we have already noted TIG welding uses variable current.
Different electrodes, base metals, and welding processes require different shielding gases. For all TIG applications, use 100 percent argon. For all MIG aluminum applications use 100 percent argon also. For MIG welding on stainless steel, a "tri-mix" blend should be used. Tri-mix consists of 90 percent helium, 7.5 percent argon, and 2.5 percent of carbon dioxide. As you become more involved with different alloys or procedures, the shielding gas requirements change, so you'll need to research which gas combination will work best for your specific jobs before you proceed.
One final thing to think about is welding safety. Arc welding safely always requires proper safety gear to protect you from the harmful sparks, heat, and ultraviolet rays that can burn skin and eyes.