SP-125 PLUS
B-6
OPERATION
9. To stop welding, release the gun trigger and then
pull the gun away from the work after the arc goes
out.
10. 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 the
SP-125 Plus.
Cleaning Tip And Nozzle
Clean the contact tip and nozzle to avoid arc bridging
between the nozzle and contact tip which can result in
a shorted nozzle, poor welds and an overheated gun.
Hint: Anti-stick spray or gel, available from a welding
supply distributor, may reduce buildup and aid in spat-
ter removal.
PROCESS GUIDELINES
The SP-125 Plus can be used for welding mild steel
using the GMAW, single pass, process which requires
a supply of shielding gas or it can be used for the self
shielded, Innershield electrode process.
The recommended gas and electrode for GMAW is
welding grade mixed CO
2
and Argon (75-80%) gas
and 0.025” (0 6 mm) diameter Lincoln L-56 mild-steel
welding wire [supplied on 121/2 Ib (6 kg) spools]. For
14 gauge (2,0 mm) and thinner CO
2
, or blended gas is
acceptable. A mixed gas consisting of 75 to 80%
Argon and 20 to 25% CO
2
is recommended for weld-
ing on heavier gauge [12 gauge (2,5 mm) for example]
steel.
The recommended electrode for the self-shielded
process is 0.035” (0,9 mm) diameter Lincoln
Innershield NR-211-MP on 10 Ib (4,5 kg) spools. This
electrode can be used for all position welding of 20
gauge through 5/16” (1,0 – 8,0 mm) thick steel [multi-
ple passes are required for 1/4” and 5/16” (6,0 and 8,0
mm)].
The SP-125 Plus is suitable for .035" Aluminum wire
and .030" stainless wire. Refer to Table B.1 for
Recommended Procedure Settings. Aluminum wire
requires K663-1 Aluminum Welding kit. See ACCES-
SORIES section.
It is important when changing between welding
with steel wire and aluminum to exchange feeding
components due to the lubricant applied to steel
wire. Failure to do so may result in contaminated
welds when welding aluminum.
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TABLE B.1 — SP-125 Plus Welding Procedures
CHANGING MACHINE OVER TO
FEED OTHER WIRE SIZES
The SP-125 Plus is shipped from the factory ready to
feed 0.023-0.025” (0,6 mm) diameter wire. To operate
the SP-125 Plus with other sizes of wire, it is neces-
sary to change the contact tip and change the drive
roll over to other sizes. Refer to Changing the Contact
Tip and Changing the Drive Roll, in the MAINTE-
NANCE section, for specific information on these pro-
cedures.
WELDING WITH FCAW (Innershield)
Welding with Innershield requires an Innershield
Welding Kit. A gasless nozzle is provided in the
Innershield Welding Kit. When using Innershield elec-
trode, installing the gasless nozzle will improve visibili-
ty of the arc and protect the gas diffuser from weld
spatter. Additionally included is a gun cable liner to
permit proper feeding of .035” (0,9 mm) Innershield
wire. Refer to the ACCESSORIES section for details
on obtaining this kit.
Welding Shielding
Process Wire Gas 16 ga 14 ga 12 ga 10 ga
MIG DC+ .035 Dia 100% Argon D-4.5 H-6.5 H-6.5 J-7.5
4043 Aluminum
Wire
MIG DC+ .035 Dia 100% Argon C-5.5 D-6 G-8.5 H-9.5
5356 Aluminum
Wire
MIG DC+ .030 Dia 98% Argon/ D-3 F-4 J-5 J-6.5
308L Stainless 2% Oxygen
Steel Wire
WARNING
Use of the GMAW process with the SP-125 Plus on
thicker materials than recommended may result in
poor welds. The welds may “look” good, but may
just be “sitting” on top of the plate. This is called
“cold casting” and will result in weld failure.
CAUTION
