Taylor 1200E, Operating Manual

Page: 23 / 43

V - 21A
STUDWELDING TECHNIQUES
23
9. WELDING CLOSE TO CORNERS, FLANGES AND OTHER OBSTACLES.
When welding close to the edge of a plate, in / on a corner, on long strips of narrow plate
etc. An effect known as "arc
- blow" occasionally will produce an uneven fillet, in such a fillet,
most of the material is blown to one side of the stud. "Arc - blow" is caused by the magnetic
forces surrounding the arc being intensified in one direction, due to the presence of an air
gap or the proximity of a large mass of magnetic material. It is dependant on a number of
factors, size of stud, shape of component, position of earth connection, current density etc.
No hard and fast rules can be applied to correct it. The following methods are generally
helpful, but if satisfactory results cannot be obtained, our field staff will be pleased to
advise you. Check that no other fault is present by welding a few studs on to a test piece
and inspecting the fillet formation, before deciding that "arc
- blow" is causing the uneven
fillet.
"Arc - blow" can sometimes be corrected by placing a block of steel near the position of the
weld area, on the opposite side to that at which the fillet has blown. When welding near
the edge of a plate, the fillet will be blown towards the general mass of material, i.e.. away
from the edge. The block in this case should therefore be placed at the edge the plate,
touching it, thus providing a more evenly distributed magnetic field. The earth
connection can be located immediately below the position of the stud weld, this latter is
not always practicable, since it requires the earth connections to be moved frequently. The
use of two earth connections, spaced evenly across the welding area, is also advisable.