Draper 69339, Instruction Manual

– 7 –

7.2  MMA/ARC WELDING FILLER ROD 

(ELECTRODE) SELECTION – FIG.1

The correct selection of electrode size and type will vary 

for each application dependent upon material thickness, 

material type, amperage and equipment, however as a 

guide the figures below provide an indication.

MMA Electrode 

Ø

Material 

Thickness

Amp Range

1.6mm

1.0mm

30 – 50

2.0mm

2.0 – 2.5mm

50 – 75

2.5mm

2.5 – 3.0mm

75 – 105

3.2mm

3.0 – 4.0mm

105 – 140

1 

FIG.

8. OPERATION

8.1  BASIC MMA/ARC WELDING 

PROCESS OVERVIEW – FIG.2

During the MMA/ARC welding process, the arc created 

between the work piece and the consumable electrode rod 

melts the parent metal and the filler metal in a weld pool.
The electrode’s flux coating reacts during this process 

and develops into a shield gas protecting the weld bead. 

Part of this reaction leaves a trail of slag which solidifies 

behind the weld pool protecting the weld as it cools.
The most common varieties of electrodes are cellulosic, 

rutile and basic, the latter two being the most general 

purpose.
Selection of the appropriate specification electrode is 

important to achieve a good quality weld. Seek guidance 

if unsure of selection.

2 

FIG.

8.2  MMA/ARC MACHINE OPERATION 

– FIG.3

− Prepare the joint(s) to be welded.

− Insert the electrode suitable for the application into  

the electrode holder 

(9)

 while pressing lever 

(9.1)

.

− With the earth clamp and electrode holder 

connected, connect the machine to the power supply. 

The power display will illuminate as confirmation. Set 

the amperage appropriate to the selected electrode 

size.

− Secure the earth clamp to a clean sound section of 

the parent metal in the vicinity to the intended weld.

− With all safety equipment in place and personal 

protective clothing on begin welding.

− Lower the electrode down toward the parent metal 

and strike the arc.

− The position of the electrode is critical to the arc and 

the end result.

− Achieving a good weld will take practice. For more 

detailed information refer to a industry standard 

welding publication and/or seek training on the 

subject.

− Use of an anti-spatter spray – Draper stock 

No.05709 – will help to achieve a cleaner finished 

weld.

3 

FIG.

(9)

(9.1)

8.3  DIRECTION OF WELD – FIG.4

− Strike the initial arc perpendicular to the parent metal 

before moving the electrode holder in the direction of 

travel 20-30° (Z,Y axis) and tilt it 20-30° (Z,X axis).

− Maintain a constant gap between the electrode tip 

and the weld pool of approximately 1 – 1.5 × the 

diameter of the electrode for a stable arc.

Z

-Z

-X

-Y

XY

Direction 

of weld

4 

FIG.