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8.5 Spot welding
There are three methods of spot welding: Burn-Through, Punch and Fill, and Lap. Each has
advantages and disadvantages depending on the specific application as well as personal
preference.
1. The BURN-THROUGH METHOD welds two overlapped pieces of metal together by burning
through the top piece and into the bottom piece. With the burn-through method, larger wire
diameters tend to work better than smaller diameters. Wire diameters that tend to work best, with
the burn-through method are 0.035 inch self-shielding flux-core wire. Do not use 0.030 inch
self-shielding flux core wires when using the burn-through method unless the metal is VERY thin or
excessive filler metal build-up and minimal penetration is acceptable. Always select a HIGH heat
setting with the burn-through method and tune in the wire speed prior to making a spot weld.
2. The PUNCH AND FILL METHOD produces a weld with the most finished appearance of the three
spot weld methods. In this method, a hole is punched or drilled into the top piece of metal and the
arc is directed through the hole to penetrate into the bottom piece. The puddle is then allowed to fill
up the hole leaving a spot weld that is smooth and flush with the surface of the top piece. Select the
wire diameter, heat setting, and tune in the wire speed as if you were welding the same thickness
material with a continuous bead.
3. The LAP SPOT METHOD directs the welding arc to penetrate the bottom and top pieces, at the
same time, right along each side of the lap joint seam. Select the wire diameter, heat setting, and
tune in the wire speed as if you were welding the same thickness material with a continuous bead.
Summary of Contents for FC130i
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