Tweco 141i Fabricator - Manual (Page 73)

Fabricator 141i
Manual 0-5145 4-13 BASIC WELDING GUIDE
Joint Preparations
In many cases, it will be possible to weld steel sections without any special preparation. For heavier sections and
for repair work on castings, etc., it will be necessary to cut or grind an angle between the pieces being joined to
ensure proper penetration of the weld metal and to produce sound joints.
In general, surfaces being welded should be clean and free of rust, scale, dirt, grease, etc. Slag should be removed
from oxy-cut surfaces. Typical joint designs are shown in Figure 4-19.
Gap varies from
1/16" (1.6mm) to 3/16" (4.8mm)
depending on plate thickness
Joint
Open Square Butt
1/16" (1.6mm) max
1.6mm (1/16”)
Single Vee Butt Joint Not less than
70°
Double Vee Butt Joint
1/16" (1.6mm)
Lap Joint
Tee Joints
(Fillet both sides of the
joint)
Edge Joint
Fillet Joint
Corner Weld
Plug Weld Plug Weld
Not less than
70°
Single Vee Butt Joint Not less than
45°
1/16" (1.6mm) max
Art # A-10367
Figure 4-19: Typical Joint Designs for Arc Welding
Arc Welding Technique - A Word to Beginners
For those who have not yet done any welding, the simplest way to commence is to run beads on a piece of scrap
plate. Use mild steel plate about 1/4" (6.4mm) thick and a 1/8"(3.2mm) electrode. Clean any paint, loose scale
or grease off the plate and set it firmly on the work bench so that welding can be carried out in the downhand
position. Make sure that the work clamp is making good electrical contact with the work, either directly or through
the work table. For light gauge material, always clamp the work lead directly to the job, otherwise a poor circuit
will probably result.