Preparation

e. Where necessary punch the welding spots to make a centering point for a drill bit.

Tools required:

• Hammer
• Graver.

CAUTION: Punch in depth and at the centre of each welding spot. An off-centre punch will not allow complete removal of the welding spot, while a weak punch will not allow the drill bit to be securely guided.

f. Remove the welding spots using a de-welder or drill.

Tools required:

• De-welder
• Drill

NOTE: Where access with a de-welder or drill is not possible, use a chisel. The chisel is particularly suitable for dewelding fine sheets from thick sheets.

WARNING: Use protective gloves and goggles.

g. Remove the remaining traces of the welding spot using a chisel.

Tools required:

• Chisel
• Hammer.

PREPARATION

a. Grind the metal sheet at the welding spots to remove all traces.

Tools required:

• Prelù with brush
• Disk sander.

CAUTION: • Position the de-welder over the centre of the spot to be removed.
• To facilitate the operation, a cutting speed of appr. 1000 rpm should be used.
• Adjust the milling depth using the screw.
• Care should be taken to avoid drilling the mating components. Plug any holes by welding.
• Holes reduce the strength of the component concerned and can also give rise to water seepage.