Final answer:
In the overhead welding position, molten metal tends to accumulate at the center of the puddle due to gravity, making it challenging for the welder to maintain a consistent and defect-free weld.
Step-by-step explanation:
When welding in the overhead position, the molten metal tends to build up at the center of the puddle due to gravity. Despite the heat from the electric arc causing the rod to melt and become molten, gravity still influences the behavior of the molten metal, causing it to droop and accumulate predominantly in the middle.
The buildup in the overhead position requires a welder to skillfully manage the molten puddle to ensure a strong and consistent weld. Various techniques and adjustments in welding speed, angle, and rod choice are necessary to compensate for the downward flow of the molten metal and prevent defects like sagging or drop through.