## Welding Methods

#### Spot Welding (cont'd)

2-18

Welding Strength Test

Even if you perform the welding according to the proper conditions, the strength of the welded sections may fluctuate due to drops in the voltage and other factors. The quality of the welding cannot be evaluated unless the welded sections are destroyed.

Provide yourself with a steel plate of the same thickness and conduct a destruction test.

- If holes appear in the steel plates, this means that the welding is of standard strength.

- Drive a wedge between 2 panels near the nugget. If the welded parts do not come apart and the diameter of the nugget is more than 3 mm (0.1 in.), the welding should be satisfactory.

  1. WEDGE
  2. Stop inserting the wedge when the full size of the nugget appears.

NOTE:

It is difficult to perform spot welding in the following circumstances:

- When it is not possible to remove any rust or paint attached to the welding surfaces.
- When the tip of the spot welder cannot be inserted into the welding section.
- When the welding surfaces can be seen from the outside and welding will impair the exterior appearance.

In all these cases, the gas welding method should be employed. Moreover, if it is not possible to perform spot welding because of space restrictions, plug welding using on the arc welding method may be performed instead. For plug welding, the sections to be welded must be close together.