D/F Nozzles (also called gas cups) provide a given amount of shielding gas coverage to the weld pool, according to their size (anywhere from 1/4- to 5/8-inch ID). For example, a smaller nozzle provides less gas coverage than a larger one. Nozzles also vary in price and performance.

The most cost effective are 90 or 95 percent alumina oxide nozzles, which work adequately for lower amperage applications. These nozzles, however, do not resist thermal shock on higher amperage applications very well and tend to deteriorate or crack and fall off.

Lava nozzles cost more than alumina oxide nozzles and are more resistant to cracking. These nozzles work well on medium to high amperage applications.

The bottom line when choosing TIG consumables is that factory OEM parts provide you with the durability and performance you need. A wide variety of options exist for back caps, collets and collet bodies, gas lenses and nozzles, all of which offer distinct advantages, disadvantages and cost considerations. For less critical applications, the less expensive alumina nozzles provide adequate performance. However, if you need high performance, it is well worth your while to purchase more expensive, long-lasting lava nozzles or cups. Doing so minimizes the chance of consumable failures that could ultimately increase the cost for rework associated with weld inconsistencies.