LORCH Handy 200 BasicPlus Manuel D'utilisation page 43

Basics of welding
Basically AC and DC may be used for TIG
welding. The type of current and polarity de-
pend on the material to be welded.
Non- or low-alloyed steel, high-alloyed steel,
and copper, as well as titanic an tantalum
are welded with DC. The electrode is con-
nected at the minus pole because of the
stronger current loading.
When welding of aluminium and magnesi-
um, as well as their alloys, ACwill be used
in order to tear up the high-melting and
tough oxide skin covering the melting bath
or being on the working piece. Is the oxide
skin missing, e.g. is has been welded on the
same part for a longer time, consequently,
the arc can be instable or breaks up from
time to time.
Shape of the electrode tip
Tungsten electrodes has to be ground al-
ways lengthwise, because the grinding
marks crosswise cause a nervous/flattering
arc.The shape of the electrode for DC-wel-
ding has to be sharp as a pencil. The angle
of the point depends on the welding current.
10.15
Current [A]
10 - 50
50 - 200
> 200
Tungsten electrodes has to be ground al-
ways lengthwise, because the grinding
marks crosswise cause a nervous/flattering
arc.The shape of the electrode for DC-wel-
ding has to be sharp as a pencil. The angle
of the point depends on the welding current
It is enough when AC-welding to sharpen
slightly edge of the electrode. After a short
time, a round to slightly convex form is built.
If the electrode tip is polluted due to dipping
into the weld pool or touching the filler wire,
the respective part of the electrode shall be
completely ground off. Restore the original,
pointed shape. Grind in longitudinal direc-
tion.
Electrode angle
15 - 30°
30°- 45°
45 - 75°
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