Linde BOC Smootharc TIG 200 ACDC, Operating Manual

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BOC Smootharc TIG 200 ACDC Operating Manual

17.3  Welding Technique

Successful welding depends on the following factors: 

• selection of the correct electrode 
• 

 selection of the correct size of the electrode for the job 

• correct welding current 
• correct arc length 
• correct angle of electrode to work 
• correct travel speed 

• correct preparation of work to be welded. 

17.4  Electrode Selection 

As a general rule the selection of an electrode is straight forward, in that 
it is only a matter of selecting an electrode of similar composition to the 
parent metal. It will be found, however, that for some metals there is a 
choice of several electrodes, each of which has particular properties to 

suit specific classes of work. Often, one electrode in the group will be 

more suitable for general applications due to its all round qualities. 

The table (page 27) shows just a few of the wide range of electrodes 

available from BOC with their typical areas of application. 

For example, the average welder will carry out most fabrication using 
mild steel and for this material has a choice of various standard BOC 
electrodes, each of which will have qualities suited to particular tasks. 
For general mild steel work, however, BOC Smootharc 13 electrodes 
will handle virtually all applications. BOC Smootharc 13 is suitable for 
welding mild steel in all positions using AC or DC power sources. Its easy-

striking characteristics and the tolerance it has for work where fit-up 

and plate surfaces are not considered good, make it the most attractive 
electrode of its class. Continuous development and improvement of 
BOC Smootharc 13 has provided in-built operating qualities which 

appeals to the beginner and experienced operator alike. For further 

recommendations on the selection of electrodes for specific applications, 

see table page 27. 

Electrodes and Typical Applications 

Name

AWS Class. Application 

BOC Smootharc 13 E6013

A premium quality electrode for general 
structural and sheet metal work in all 
positions including vertical down using low 
carbon steels 

BOC Smootharc 24 E7024 

An iron powder electrode for high speed 

welding for H-V fillets and flat butt joints. 

Medium to heavy structural applications in 
low carbon steels

BOC Smootharc 18 E7018-1

A premium quality all positional hydrogen 
controlled electrode for carbon steels in 
pressure vessel applications and where high 
integrity welding is required and for free-
machining steels containing sulphur 

BOC Smootharc S 
308L

E308L

Rutile basic coated low carbon electrodes for 

welding austenitic stainless steel and difficult 

to weld material 

BOC Smootharc S 
316L

E316L

BOC Smootharc S 
309L

E309L

Rutile basic coated low carbon electrode 
for welding mild steel to stainless steel and 

difficult to weld material 

Electrode Size 

The size of the electrode is generally dependent on the thickness of the 
section being welded, and the larger the section the larger the electrode 
required. In the case of light sheet the electrode size used is generally 
slightly larger than the work being welded. This means that if 1.5 mm 
sheet is being welded, 2.0 mm diameter electrode is the recommended