Product Manual

Page 32 of 47
e. 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.
i. 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 the HIGH heat setting with the burn-through
method and tune in the wire speed prior to making a spot weld.
ii. 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 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.
iii. 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.
5. SPOT WELDING INSTRUCTIONS
a. Select the wire diameter and heat setting recommended above for the method of spot
welding you intend to use.
b. Tune in the wire speed as if you were going to make a continuous weld.