Operation, Side view end view 30° 30 – Lincoln Electric BULLDOG SVM208-A User Manual

Page 31

OPERATION

B-15

BULLDOG® 140

Overhead Welding

Various techniques are used for overhead welding.
However, in the interest of simplicity for the inexperi-
enced welder, the following technique will probably
take care of his needs for overhead welding:

1. Use 1/8” (3.2mm) 90-105 A or 3/32” (2.5mm) 70 A

AWS 6011 electrode on AC.

2. Put the electrode in he holder so it sticks straight

out.

3. Hold the electrode at an angle approximately 30°

off vertical, both seen from the side and seen from
end. (See drawing below.)

It is important to hold a VERY SHORT arc. (A long arc
will result in falling molten metal; a short arc will make
the metal stay.)

If necessary, and this is dictated by the appearance of
the molten puddle, a slight back and forth whipping
technique may be used to prevent “dripping”.

Welding Sheet Metal

Welding sheet metal presents an additional problem-
burn through. Follow these simple rules:

1. Hold a very short arc. This, together with the prop-

er travel speed, will eliminate burn through.

2. Use 1/8” (3.2mm) or 3/32” (2.5mm) AWS 6011.

3. Use low amperage. 75 A for 1/8” (3.2mm) elec-

trode, 70 A for 3/32” (2.5mm) electrode.

4. Move rapidly enough to stay ahead of the molten

slag. A whipping technique may be used to further
minimize burn through.

5. If you have a choice, use lap joints rather than fillets

or butts; the double thickness effect of a lap joint
makes it much easier to weld without burning
through.

Hardfacing (To Reduce Wear)

There are several kinds of wear. The two most often
encountered are:

1. Metal to Ground Wear: Plowshares, bulldozer

blades, buckets, cultivator shares, and other metal
parts moving in the soil.

2. Metal to Metal Wear: Trunnions, shafts, rollers and

idlers, crane and mine car wheels, etc.

Each of these types of wear demands a different kind
of hardfacing electrode.

When applying the proper electrode, the service life of
the part will in most cases be more than double. For
instance, hardfacing of plowshares results in 3-5 times
more acreage plowed.

How to Hardface the Sharp Edge (Metal to Ground
Wear)

1. Grind the share, approximately one inch along the

edge, so the metal is bright and clean.

2. Place the share on an incline of approximately 20-

30°. The easiest way to do this is to put one end of
the share on a brick. (See drawings) Most users
will want to hardface the underside of the share, but
some might find that the wear is on the top side.
The important thing is to hardface the side that
wears.

3. Use 1/8” (3.2mm) Wearshield at 80-100 A. Strike

the arc about one inch from the sharp edge.

Side View

End View

30°