Spot Weld Mode; Stitch Weld Mode; Avoiding Wire Feeding Problems; Fan Control - Lincoln Electric IDEALARC SP-255 Operator's Manual

12. When no more welding is to be done, close valve
on gas cylinder (if used), momentarily operate
gun trigger to release gas pressure, and turn off
SP-255.

SPOT WELD MODE

Arc spot plug welds are used when continuous welds
are not needed or to hold thin sheet metal together
prior to stitch welding or continuous welding. Plug
welds are made by using a punch to make a 3/16 inch
(4.8 mm) diameter hole in the top sheet and arc weld-
ing through the hole into the back sheet.
Spot On Time sets welding time. Start with a dial set-
ting of about 1.2 seconds.
To make an arc spot plug weld, punch 3/16 inch (4.8
mm) holes in top sheet. Set the procedure for the
metal thickness to be welded. Install spot weld nozzle
(if available) on gun and press it against the top sheet
so the top and bottom sheets are tight together. Close
trigger and hold it closed until the arc goes out. If a
spot weld nozzle is not used, smoother welds will
result by moving the welding wire in a small circle dur-
ing the weld.

STITCH WELD MODE

Used to weld thin material where warpage and burn-
through are a problem. Proper adjustment of ON and
OFF times and arc travel speed permits welding thin
sheet metal with small welds, minimum distortion, and
no burnthrough.
Stitch On Time sets welding time. Start with a dial set-
ting of 0.5 seconds. Raise setting to increase penetra-
tion and weld size; lower setting to reduce burn-
through and distortion.
Stitch Off Time sets off time. Start with a dial setting
of 0.5 seconds. Raise setting to reduce burnthrough;
lower setting to make weld flatter and smoother.
To weld, set the procedure for the metal thickness to
be welded. Close trigger and hold it closed for length
of seam. Hold gun in one place during ON time and
move gun just beyond edge of molten metal during
OFF time.
NOTE: For smoothest welds on thinner metal, point
gun slightly toward direction of travel.
OPERATION
AVOIDING WIRE FEEDING
PROBLEMS
Wire feeding problems can be avoided by observing
the following gun handling procedures:
a. Do not kink or pull cable around sharp corners.
b. Keep the electrode cable as straight as possible
when welding or loading electrode through cable.
c. Do not allow dolly wheels or trunks to run over
cables.
d. Keep cable clean by following maintenance
instructions.
e. Use only clean, rust-free electrode. The Lincoln
electrodes have proper surface lubrication.
f. Replace contact tip when the arc starts to become
unstable or the contact tip end is fused or
deformed.
g. Keep wire reel spindle brake tension to minimum
required to prevent excess reel over-travel which
may cause wire "loop-offs" from coil.
h. Use proper drive rolls and wire drive idle roll pres-
sure for wire size and type being used. (See Drive
Roll Kits in Accessories section.)

FAN CONTROL

The fan motor is thermostatically controlled to provide
cooling for the transformer and other components
only when required. Even though the power switch is
on, the fan motor will not run when the machine does
not require fan cooling, such as when first turned on,
or when welding at low current or duty cycle proce-
dures.
INPUT LINE VOLTAGE
PROTECTION
HIGH LINE VOLTAGE—If the line voltage exceeds
121% of rated input voltage, the output will be
reduced to the lower level to protect voltage rating of
the capacitor bank. A HIGH LINE message will be dis-
played if the output has been reduced (see Section on
Explanation of Prompting and Error Messages).
LOW LINE VOLTAGE—You may not be able to get
maximum output from the machine if the line voltage
is less than rated input. If the output you want is not
obtainable because of insufficient line voltage, a LOW
B-13
IDEALARC SP-255