Page 58 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Soldering machines of different designs are used for wave soldering, cascade soldering and jet soldering. The
following methods are used for soldering
1 Resistance soldering

2 Induction soldering
3 Oven soldering
4 Soldering in vegetable oil
5 Soldering by hot gas
6 Soldering with pot and ladle

Used for soldering large size jobs like UG cable joints. The solder is kept in a pot which is heated by blowlamp or
charcoal. Initially soldering surface is cleaned and a coat of flux is given. Heating the soldering surface is pouring
the molten solder over it. After several pouring the surface attains the same temperature of molten solder. Then
apply a coat of flux, and a molten solder is poured slowly and a fine layer of solder is formed.

Soldering aluminium cable
Soldering of aluminium conductors is more difficult than copper because of tenacious, refractory and stable
nature of aluminium oxide film which forms immediately on any aluminium exposed to air. This oxide film does not
allow the solder to wet the surface to be soldered and also prevents the solder from entering the interior surface
by capillary action. Hence special solders and fluxes are used for aluminium soldering.
Solders used in aluminium soldering
A special type solder having a small percentage of zinc is used for aluminium soldering. The brand name of
solders available in the market – ALCAP, Ker-al-lite.
Flux
In soldering aluminium conductor’s organic fluxes of reaction type free from chlorides are used. The composition
of organic fluxes de-composes at 250°c to effect the removal of the oxide film and helps to spread the molten
solder over the surface.
Commercial name – Kynal flux, Eyre No:7
Disadvantage

It will char at 360°c
Soldering process maintained up to 360°c.
Soldering precautions
Inspect the iron regularly for physical damage especially the power cord.
Keep the iron in a stand when not in use.

Keep the iron away from all part of the body and from its own power code.
A proper earth connection may be made to all mains connected.
Do not inhale the toxic fumes produced during soldering

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CITS : Power - Electrician & Wireman - Lesson 5 - 12