Material

• Alumina oxide is the material that ceramic TIG welding cups are made out of. When they're finished firing, the cups are pink in color. This is the easiest way to recognize an alumina TIG cup, but not all of these ceramic cups are the same size and shape.
  
  

Sizes

• TIG welding cups are measured in sixteenths of an inch. Each number that you increase the designation by, the nozzle increases by that much width. So a No. 4 ceramic TIG nozzle would be 1/4 inch in width, because it's 4/16 inch wide. The bigger the width, the more gas you can use at once. However, smaller sizes may be necessary for narrow diameters or for welding corners where you don't have as much room.
  
  

Cost

• Generally speaking, alumina cups are the cheapest TIG welding cups you can buy. Because of the nature of the ceramic material, these welding cups can be fired easily and mass produced. However, the bigger the cup size, the bigger the price.
  
  

Weakness

• All alumina TIG welding cups have the same weakness. While these cups are good, general welding cups because the ceramic doesn't translate heat as easily, a huge difference in the heat at the front of the welding cup and the rear of the cup can develop. This can lead to a crack developing.