Final answer:
The preferred method for starting SMAW varies depending on the application and personal preference. Scratch start and tapping start are commonly used techniques in SMAW.
Step-by-step explanation:
The preferred method for starting Shielded Metal Arc Welding (SMAW) depends on the specific application and personal preference of the welder. However, both scratch start and tapping start are commonly used techniques in SMAW.
Scratch start involves initiating the arc by scratching the electrode against the workpiece and then quickly withdrawing it to establish the arc. This method is suitable for thicker materials and welding in vertical or overhead positions.
Tapping start, on the other hand, involves lightly touching the electrode to the workpiece and tapping it to create a short circuit. This short circuit produces enough heat to melt the electrode, which then establishes and sustains the arc. Tapping start is commonly used for thinner materials and welding in horizontal or flat positions.