Lincoln Electric BULLDOG SVM208-A Service Manual page 33

B-17
In some instances a back-up strip may be used and
plates may be gapped 1/8" (3.2mm) or more, as shown
in figure (b).
(b)
(a)
Three ways to prepare plates where
complete penetration is necessary.
On sections where only a sealed joint is required and
strength is not important, the joint may be welded after
slightly veeing out the seam as shown in figure (d)
below.
(d)
Single and double beads, with and without
beveling for tight, partial strength joints.
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 ELECTRODES may be classified into
the following groups:
Out-of-Position Group (AWS 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. They are 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 com-
pletely cleaned from the steel. These electrodes are
typically used with motions "A" and "B" (see drawing)
for the first pass on vertical-up welds.
OPERATION
Scrap steel back-up strip
(c)
(e)
BULLDOG® 140
High-Speed Group (AWS E6013)
This group includes electrodes which have a moder-
ately forceful arc and deposit rates between those of
the out-of-position and high-deposit electrodes.
They are primarily general purpose production elec-
trodes especially for downhill fillets and laps or short
and irregular welds that change direction or position.
They are also widely used in maintenance and recom-
mended for sheet metal fillet and lap welds. Motion "D"
(see drawing) is generally used for vertical-up welding,
but motions "A" and "B" are also suitable.
Low Hydrogen Group (AWS E7018)
These electrodes are generally called "low hydrogen".
The name comes from the fact that their coating con-
tains little hydrogen in either moisture or chemical
form. Low hydrogen electrodes offer these benefits:
outstanding crack resistance, lowest porosity on
phur bearing steels, and X-ray quality deposit capabil-
ity. Thus, they are the first choice when welding "prob-
lem" steels. E7018 can be used in all positions, with
Motion "C" (below) 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 electrode away slowly.
these electrodes dry. Electrodes, when not used with-
in a few hours after a container is opened, must be
stored in heated cabinets.
E
D
C
B
SIDE
A
VIEW
B-17
sul-
ALWAYS keep
Motions
START
F
G