What is the purpose of the filler rod in TIG welding?

• A. Adds material to strengthen the weld joint
• B. Improves electrical efficiency of the welder
• C. Cools the weld area
• D. Enhances gas flow efficiency

Answer: (A)

The filler rod’s job in TIG welding is to supply material that melts into the molten pool to fill the joint and form a continuous weld bead. As you feed the rod into the arc, its metal melts and fuses with the base metals, increasing the weld’s cross‑section and strength. Using the right filler metal lets you tailor the joint’s properties—such as strength and corrosion resistance—to match or enhance the base metals, and it’s especially important when the joint has gaps, needs additional material, or requires thicker sections.

The other options aren’t the purpose of the filler rod. It doesn’t improve the welder’s electrical efficiency, and it doesn’t cool the weld area. Shielding gas flow is about protecting the molten pool from the atmosphere, not about the filler metal.