Impax IM-MMA130-IWK Manual page 24

MMA OPERATION
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 6.0mm thick and a 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.
The Welder
Place yourself in a comfortable position before
beginning to weld. Get a seat of suitable height
and do as much work as possible sitting down.
Don't tense your body. Relax and you will find
that the job becomes much easier. Wear a
leather apron and gauntlets. This will protect you
from being burnt or sparks setting alight to your
clothes.
Place the work so that the direction of welding
is across, rather than to or from, your body. The
electrode holder lead should be clear of any
obstruction so that you can move your arm
freely along as the electrode burns down. If the
lead is slung over your shoulder, it allows greater
freedom of movement and takes a lot of weight
off your hand. Be sure the insulation on your
cable and electrode holder is not faulty,
otherwise you are risking an electric shock.
Striking The Arc
Holding a face mask in front of your face stroke
the electrode point on the workpiece as if
striking a match.
Maintain a steady gap between the end of the
electrode and the workpiece of approximately
2mm (Fig.9).
Maintain this distance as constantly as possible
during the weld remember that the angle of the
electrode to the work piece must be 20-30°
(Fig.10).
Do not hit the electrode on the workpiece as
this may damage the electrode. Withdraw with a
clean movement at the end of the welding run.
Fig 9
Fig 10
Note: This is the most difficult aspect for most
beginners. It is recommended that you practice
on some scrap material in order to get a feel of
the operation.
If the electrode is not withdrawn quickly enough
once the arc is primed, there is a possibility that
the electrode will weld itself to the workpiece.
Should this happen, give it a sharp tug to free it,
and try again. If this fails to free it, turn off the
machine immediately as it will quickly overheat.
If you withdraw the electrode too far once the
arc is primed, you will lose the arc and have to
try again.
Inspect the job carefully. With a correct
combination of electrode size and current
setting the area of weld should be complete
fusion of the electrode and parent metal/s. Any
slag which forms on the surface should be
chipped away with the pick/brush supplied.
23
2mm
20º-30º