In TIG welding, what is the function of the separate filler rod?

• A. Adds material to the weld pool
• B. Acts as the shielding gas
• C. Measures arc intensity
• D. Reduces heat input

Answer: (A)

In TIG welding, the separate filler rod’s job is to add material to the weld pool. The tungsten electrode is non-consumable, so it simply provides the heat to melt the base metal, while the filler rod is fed into the molten pool to deposit additional metal and build up the weld bead. Choosing the right filler alloy helps match or complement the base metal to achieve the desired strength and corrosion resistance. The shielding gas protects the weld area (including the filler rod) from contamination, but it’s supplied separately from the filler material. The filler rod isn’t used to measure arc intensity, and it doesn’t inherently reduce heat input—that control comes from the welding current and travel speed.