Tweco FP-260 - Manual (Page 14)

SPOT WELDING
Spot welding is possible by replacing the welding nozzle with a spot welding nozzle. You can buy the spot
welding nozzle from any supplier of Firepower Welding Systems. Spot welding can be performed on carbon
steel sheets of up to 18 gauge thickness.
Place the spot welding nozzle on the upper sheet. Push the nozzle firmly on the torch, being sure that the top
sheet is in contact with the bottom one. For spot welding, the machine must be set at maximum current and
maximum wire speed. We recommend 0.030” welding wire.
Then press and hold the trigger. Welding stops automatically after the pre-selected time.
ADJUSTMENT OF THE POWER SOURCE
Set the voltage. Use the correct “stick out.” The wire
“stick out” is the distance between the contact tip and
the workpiece. The wire “stick out” (sometimes
improperly called the arc length) should remain in the
0.2”-0.4” (5mm-10mm) range to obtain the best weld-
ing (and sound) performance.
1. Position the voltage switch in the desired position
(see Table 1). Select lower position for lower thick-
ness and higher settings for higher thickness.
2. Adjust the wire speed. Start using a trial metal sheet
thoroughly cleaned of layers of rust or paint. Connect
the ground cable to the workpiece. Adjust the wire
speed at the high setting. Press the torch switch.
Start welding, squeezing the torch switch and decrease the wire speed gradually.
Continue to decrease the wire speed and listen to the sound. The sound will change from a
crackling noise to a regular and strong buzzing (similar to the sound of frying bacon). This
buzzing sound indicates the correct wire speed for the workpiece being welded. When the
current regulation is changed, reset the wire speed. ALWAYS start from a higher wire speed.
This operation prevents damage to the contact tip during welding. During welding, keep the
torch at a 45º angle from the workpiece. Keep the nozzle at 1/4”-1/2” from the workpiece.
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Figure 6: Power Source
Table 1:Approximate Settings for Welding