Hard facing generally involves the Stick or MIG process and uses special (and usually expensive) filler metal to build up the overall surface of the metal. These beads are often not laid solid across the entire face of the metal, but in random or organized patterns that intersect or overlap to provide a raid, bumpy like surface that takes the brunt of the wear or impact. Hardfacing is done to improve either abrasive wear or impact resistance of the metal.

The second method is known as “metallizing”. This is a special welding process in which nearly or all of the entire affected area is coated with molten spray of metal. This spray is used to build up the overall surface so that in many cases the original dimensions can be restored to the metal, such as in a crankshaft in an engine is deeply scored or overly worn on the journals. A special machine sprays tiny pieces of molten metal onto the crankshaft, building up the surface. Once it is sufficiently built up the area is turned back down in a lathe and polished so that it can be reused.

AC frequency has been covered before. However, many people fail to realize just how important this feature is, especially if they have never used an inverter with features like this before. Standard transformer welders don’t have any choice but to operate on the same frequency that is supplied to the welding machine through its primary transformer. In the US, that is 60 hertz. Though that is adequate for many welds made in aluminum, it is far from ideal. A more ideal setting would be twice that at 120Hz. This level focuses the arc cone, and improves arc stability. Inverters excel in this because the frequency is generated by electronic components rather than the input power line.

AC balance gives a choice between penetration, and cleaning. Older transformer TIG welders have pretty much the input power line balance of 50/50 ratio between Electrode Negative and Electrode Positive. This offers typically more “cleaning” than is required to break up the oxide layer on aluminum. And it also overheats the tungsten, creating a molten ball on the tip of the tungsten, destabilizing the arc. A sharp tip can be maintained while increasing the penetration of the welder with just a 20-30 percent setting of Electrode Positive. Again, inverters open up the possibilities here by offering adjustable balances. Even when times call for it, inverters like the Everlast PowerTig series can operate at nearly 90% or more of full electrode positive, creating huge amounts of cleaning. Though that is unusual, and a little harsh to weld with, it is nice to know you have that adjustability at your finger tips.

Next you will typically see a setting for Pulse width, Pulse Balance or Pulse time on. This is sometimes referred to as pulse duty cycle, but is often avoided because of the confusing terms involved with actual welder operation times referred to as duty cycle. The length of each stage of the pulse cycle is controlled by setting this function. It means that you can make the high amp stage of the pulse cycle longer or shorter than the low amps stage of the pulse cycle. Each half cycle doesn’t have to be balanced…it can be skewed to achieve the best result between melting and freezing. Even though the pulse is happening several times a second, each half phase of the pulse can be metered to give optimum results.

Most simply defined, pulse is a rapid oscillation between two pre-selected amp levels, one consisting of a high amp value and one consisting of a lower amp value. The high amp values represent a “penetrating” phase of the pulse, and the low amp value represents a cooling stage of the pulse, in which little or no melting of the parent metal occurs. The high amp portion of the pulse is when the filler rod should be added. The low amp portion of the pulse is the portion of the pulse when the torch should be moved forward. One complete cycle between high and low amp level in one second is one Hertz, or one pulse per second (pps). The frequency of most of these units is adjustable. The adjustability of the pulse frequency is important as well in the width of the arc cone. The faster the pulse the more narrow and constricted the arc becomes allow it to be pointed into tight corners.

To stop the “shakes”, consider using a cutting guide, where you can draw the torch along a solid cutting guide. Make sure it is smooth, and compatible with the torch you are using. Usually a small piece of flat bar is all that is needed. Some people use a piece of wood trim. What is important is that it is true and straight. For circles, a circle cutter can be fabricated or bought from online or from your local welding supply store. For varied curved cuts, rough templates can often be made from a “free hand” run, then ground or machined smooth to offer a smooth guide surface for the torch side to run on. Also, blood sugar, and fatigue play an often overlooked role in how well you can cut. Believe it or not, late afternoon cuts between lunch and supper can yield the worst cuts. Try eating a small snack or meal whenever it’s been more than a couple hours after meal time. This will help increase hand/eye coordination, and steady the nerves as well.

1)       “Blowback” start. This start type uses  air pressure supplied to the cutter to force a small piston or cartridge inside the torch head back to create a small start between the inside surface of the consumable, ionizing the air, and creating a small plasma flame. This also creates a “pilot arc” that provides a plasma flame that stays on, whether in contact with the metal or not. This is a very good start type that is now used by several manufacturers. It’s advantage is that it requires somewhat less circuitry, and is a fairly reliable.

2)      High Frequency start. This start type is widely employed, and has been around the longest. Although it is older technology, it works well, and starts quickly. But, because of the high frequency high voltage power that is required generated to ionize the air, it has some drawbacks. It often interferes with surrounding electronic circuitry, and can even damage components. Also a special circuit is needed to create a Pilot arc. Inexpensive models will not have a pilot arc, and require touching the consumable to the work to start. Employing a HF circuit also can increase maintenance issues, as there are usually adjustable points that must be cleaned and readjusted from time to time.

3)     A much less, common and more expensive start time, is an inductor circuit start. This uses a high voltage, lower frequency current to ionize the air. Torches are similar to the HF torches, if not identical. The start is very quick, and interference is minimal. However, it is a more costly design, due to the component requirements to make such a design. This start would seem ideal compared to HF and blowback, if the cost was more reasonable. Very few companies use this design, because of it.