Preparation of Work2-1 Welding Methods2-17

Welding Methods2-17

Spot Welding

Spot welding is also known as resistance spot welding, and it is the most suitable method of welding for vehicles. It has 3 main features: the welding can be performed instantaneously, it has minimal effect on the source material and it has a minimum affect on distortion to the absolute minimum. However, please remember to remove all paint and other impurities from the surface of the material you intend to weld for reliable results.

Welders

Welding Conditions:

When performing spot welding, make sure that you conform to the following conditions: use the correct current, conductivity time, welding pressure, holding time and shutdown time recommended for the spot welder.
Please bear in mind the following points when welding :

Welding Methods (cont'd)2-18

Spot Welding (cont'd)

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.

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.

2-19

Carbon Dioxide Arc Welder (MIG Arc Weld)

This welding process uses inexpensive carbon dioxide instead of expensive inert gases as a shielding means. Consumable metal electrodes are employed. It has a wide range of applications, including butt welding of a thin plate, fillet welding, plug welding and MIG spot welding. In terms of the weld strength, it is also highly stable.

Welders:

CAUTION: Disconnect the negative battery cable before arc welding.

Welding Methods:

Plug Welding Conditions:

Plate thickness and weld holes

Unit: mm (in.)

Plate thickness	~ 1.0 (0.04)	1.0 (0.04) ~ 1.5 (0.06)	1.5 (0.06) ~
Weld hole diameter	5 (0.2)	6.5 (0.26)	8 (0.3)

Welding Methods (cont'd) 2-20

Gas Welding

Gas welding is indispensable for body repair because of the broad range of its applications to join the body panels, cut the materials that construct the body, apply heat to reform panels and also because it is easy to get hold of the tools.

However, this method requires experience.

Welders:

Welding Methods:

Preparation of Work2-1 Welding Methods2-17