Manual electric arc welding with coated electrodes is the most common form of welding. The abbreviated name SMAW (Shielded metal arc welding*) or MMA (manual metal arc welding) is usually used.

Using an electric current (either alternating current or direct current) an electric arc is formed between the metal to be welded and the electrode used, producing its fusion and its deposit on the welded joint. The electrodes are usually made of mild steel, and are coated with a flux material that creates a protective atmosphere that prevents oxidation of the molten metal and favors the welding operation. The coated electrode used in arc welding was invented by Oscar Kjellberg.

The polarity of the electric current affects the transfer of heat to the joined parts. Normally the negative pole (-) is connected to the electrode (we weld with direct polarity), and to weld very thin materials the positive pole (+) can be connected to the electrode (we weld with reverse polarity).

The most favorable position for welding is the plane (PA) but they can be carried out in any position.

The intensity and voltage suitable for the welding operation are obtained using a transformer. Through different systems applied to the secondary, various voltages can be obtained, adapting the power of the arc to the size of the pieces to be welded. This equipment exists in very simple versions that allow small DIY jobs to be carried out.

Source: technique 7.

Manual stick electric arc welding equipment typically consists of a constant current source and electrode, with an electrode holder, an 'earth' clamp and connecting cables connecting these to the current source.

When carrying out this type of work, it must be taken into account that the radiation generated in the electric arc (luminous, ultraviolet and infrared) can cause irreversible damage to the retina if one looks directly at the welding point, in addition to skin burns.

For eye protection there are screens with special crystals, called inactinic crystals, which have different levels of retention of harmful radiation depending on the intensity used, thus making the activity completely safe. They are classified by shades, the most used being shade 11 or 12 (120 A), they are tinted green or blue and are classified according to different standards. There are automatic helmets in which when you start welding the protection is automatically activated and when you stop welding, the eye protection is removed.