Lincoln Electric IM556 AC-235 - Manual (Page 21)

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If the part being brazed does not get hot enough, increase
the current or hold the torch closer to the work. Whenever
possible, have the joint horizontal to secure best flow of
molten filler rod.
Soldering
The arc torch can be used to solder copper piping and other
copper, tinned and galvanized parts. Best results are
obtained with overlapping pieces. Clean the surfaces to be
soldered and cover them with soldering flux to prevent oxi-
dation and to speed soldering. Acid core solder produces
good results.
The best soldering can be done on the lowest current tap of
the welder. Use approximately 1/4" (6.4mm) diameter car-
bon and make certain to bring it into firm contact with the
piece to be soldered to avoid arcing. Simply play the arc on
the area to be soldered and feed solder into the joint as it
reaches proper temperature. After the soldering is complet-
ed, the carbon must be removed quickly to prevent arcing.
Never use so much heat that the solder boils.
Heating, Bending and Straightening
Choose the carbon size and current setting depending upon
the thickness of the metal to be heated. Play the arc over the
section to be heated until the desired temperature is
reached. For bending this is usually a dull red color on ordi-
nary mild steels.
Do not hold the carbons too close to the work. Arcing the
surface increases the tendency for the base metal to crack
when the bending is done.
Carbon Arc Torch Maintenance
The handle is held together with a screw and spring lock
washer to give just the right friction on the electrode shafts.
If the handle is removed for any reason, the screw at the
front of the handle should be turned up snugly and then
backed off 1/2 turn to give the proper friction.
Occasionally the screws in the copper jaws will bind, so it
will be advantageous to lubricate the threads with graphite
grease and work the grease well into the threaded jaw.
SELECTING ELECTRODES
Which electrode is best for the particular job . . . how do
you use it? These are important questions because the cost,
quality, and appearance of your work depends on proper
electrode selection and application. MILD STEEL ELEC-
TRODES may be classified into the following groups:
Out-of-Position Group (E6011)
This group includes electrodes which have a snappy, deep
penetrating arc and fast freezing deposits.
These electrodes are used for general purpose all-position
fabrication and repair welding; also the best choice for pipe
welding and sheet metal butt, corner and edge welds. They
can be used for repair work when dirt, grease, plating or
paint cannot be completely cleaned from the steel.
Typically used with motions “A’’ and “B’’ (below) for the
first pass on vertical-up welds.
High-Deposit Group (E6027, E7024)
This group includes the heavy coated, iron powder elec-
trodes with their soft arc and fast deposit rates. These elec-
trodes have a heavy slag and produce exceptionally smooth
beads. They are generally used for production welding
where all work can be positioned for downhand welding.
Stringer beads, with drag technique, are always preferred
over weave passes with these electrodes.
High-Speed Group (E6012, E6013, E7014)
This group includes electrodes which have a moderately
forceful arc and deposit rates between those of the out-off
position and high-deposit electrodes. They are primarily
general purpose production electrodes especially for down-
hill fillets and laps or short and irregular welds that change
direction or position. Also widely used in maintenance and
recommended for sheet metal fillet and lap welds. Motion
“D’’ (below) is generally used for vertical-up welding, but
motions “A” and “B” are also suitable.
Low Hydrogen Group (E7018, E7028)
These electrodes are generally called “low hydrogen.” The
name comes from the fact that their coating contains little
hydrogen in either moisture or chemical form. Low hydro-
gen electrodes offer these benefits: outstanding crack resis-
tance, lowest porosity on sulphur bearing steels, and capa-
ble of X-ray quality deposits. Thus, they are the first choice
when welding “problem” steels. E7018 can be used in all
positions, with Motion “C” recommended for the first pass
on vertical-up welds. NEVER use a whipping technique or
a long arc with these electrodes. ALWAYS fill craters by
drawing electrodes away slowly. ALWAYS keep these elec-
trodes dry. Electrodes not used within a few hours after a
container is opened must be stored in heat cabinets. LH-73
is recommended with the AC-235. Normally, DC(+) is pre-
ferred for these electrodes.