Do not use improper welding techniques. Bad techniques can cause bad welds. The following information points out potential areas of difficulty and provides some general guidelines for successful frame welding.
Most improper frame welds occur at the end of the weld in areas of the frame that are under high stress. By eliminating the end of a weld, bad welds can be prevented. This can be done by making a hole or a slot in the part to be attached and then using a fillet weld around a slot to a plug weld. Do not leave a notch at the end of a weld.
Over-welding can be harmful, especially if you are welding an area of the frame that receives high concentrations of stress.
Small cracks in a crossmember may be welded. Keep the following items in mind when welding:
| • | The underbody may be covered with a protective wax coating. Use a wire brush in order to remove any concentration of wax before welding. When finished, coat the area with new protective wax. |
| • | Do not use oxyacetylene welding equipment. |
| • | Whenever possible, use smaller diameter electrodes and make several passes. This is preferred to using a large diameter electrode and making fewer passes. |
| • | Do not use more heat than is necessary to give good penetration. |
| • | Ensure that the weld is free from craters, undercuts, slag inclusions, and porosity. |
| • | Ensure that the scale is removed from each successive pass. |
| • | If repairing a crack, grind the surface of the weld flush with the parent material. |
| • | When mounting accessories, do not weld across the flanges. |
| • | When mounting accessories, do not weld within 19 mm (3/4 in) of a flange. |
| • | Do not weld up to the edge of a part being welded to a frame. Leave approximately 6 mm (0.25 in) between the end of the weld and the edge of a part being welded to a frame. |
| • | Do not weld cast brackets to the frame. |
| • | Do not weld the flanges of cracked reinforcements and base rails together. |
| • | Do not attach the ground cable to the engine. Connect the welding machine ground cables as close to the working area as possible. |
| • | Disconnect the vehicle battery. |
| • | Do not get the welding cables near the vehicle wiring. Avoid direct contact between the welding cables and any part of the vehicle. |
