Successful pin welding and pulling requires a strong weld and a strong weld depends on several factors:
First, check that power is connected and circuit breakers/fuses are not tripped. The circuit breaker on the welder case must be reset manually if it trips.
For best results, welder should be connected directly to a properly rated electrical outlet. The use of extension cords can reduce welding power. If an extension cord must be used, it should be as short as possible and of the highest possible gage (12 AWG recommended).
The panel to be welded must be prepped to clean bright metal and be free of paint, primer, dust, grease and rust.
Weld pins must be clean and have a bright copper finish. Do not use old or corroded pins.
The electrode ground tube on the welder must be free from carbon and oxidation. Clean the tube with a wire brush to bright copper.
Too short a weld time will result in a weak weld. Increase weld time until a strong weld is achieved.