Which process is not listed as an acceptable method for joint prep and back-gouging?

• A. Plasma cutting
• B. Machining
• C. Air CAC
• D. Oxy fuel

Answer: (A)

Joint prep and back-gouging are about removing metal in a controlled way to create the proper bevel and a clean root surface for welding. The methods that the guidelines recognize as acceptable for this work are machining, air carbon arc gouging (CAC), and oxy-fuel gouging. Machining gives precise metal removal with a clean edge and minimal distortion; air CAC uses a carbon electrode in air to gouge away material cleanly and is well-controlled; oxy-fuel gouging uses a flame to remove metal and is effective for thicker sections. Plasma cutting, while great for many cuts, is not listed as an acceptable method for joint prep and back-gouging in these guidelines because its heat input and resulting surface can complicate the root pass and inspection. So plasma cutting isn’t considered an allowed method for this purpose here.