Red Seal Welding Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The rule of thumb for tungsten end prep is 2.5 times the electrode diameter (ø). This is because tungsten is a very hard and brittle metal, so a larger end prep helps prevent cracking and chipping during welding. Option A, 3 times the diameter, and option C, 2 times the diameter, may both be considered too extreme and could result in unnecessary waste of the electrode. Option D, 1.5 times the diameter, may not provide enough surface area for proper arc stability and control. Therefore, option B is the best choice.