Before spot-welding aluminum to another sheet of aluminum or to another metal, it is important to make sure that the surface resistance between the two sheets of aluminum is ideal. The surface resistance impacts how strongly the two sheets can bind to each other: Sheets with a great degree of combined surface resistance will require a higher level of welding current to thoroughly attach to each other. You can measure the surface resistance of each of your sheets of aluminum with an electrometer, then add the two resistances together. Do not attempt to use an electrometer if you do not have experience working with electrical equipment.
- Electrometer
- Latex gloves
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Instructions
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1
Attach the two clamps of the electrometer to opposite sides of one of your aluminum sheets. Make sure to be wearing latex gloves.
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2
Set the machine to automatically run a voltage current over the surface of the aluminum sheet. The machine will display the surface resistivity in ohms per square meter. Repeat this with the second sheet of aluminum.
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3
Add the two resistances of your two sheets together to obtain the combined surface resistivity. This will determine how much welding current you will need for the spot-weld.