Arc stud welding allows engineers to create flawless, durable structures with relative ease. The need for drilling, riveting, and punching is eliminated, and the process is just as effective on painted surfaces as on any other. However, some preparation is still required to ensure that the bond formed is robust.
Preparing base metal for arc stud welding
While an arc may burn through a thin layer of paint, scale, or oil, in the case of heavier coatings, some preparation is required to facilitate metal-to-metal contact needed to draw a welding arc. The area where the ground clamp fastens to the metal should also be cleaned to ensure an unobstructed current path.
Oil and grease
In most cases, oil and grease can be easily removed by wiping the surface with a dry cloth.
In cases where oil and grease are caked on and stubborn, welders should use a solvent to prep the surface.
Paint, rust, scale, and metallic contaminants
Heavy coats of paint and other contaminants must be entirely removed from the weld area. This removal can be facilitated through:
- wire brushing, and
- chemical methods.
Zinc galvanizing plating
Grinding wheels and abrasive discs are not effective for the removal of the zinc galvanizing plating that coats some surfaces. While the surface may look clean and shiny afterwards, in reality, as the zinc gets caught up in the tiny surface holes, it is merely been spread around by the wheel.
Grinding burrs, open pore abrasive discs, or chemical solutions are a better choice for removing zinc galvanizing plating.
Take time to test
In order to be sure that the surface is ready for welding, take time to perform a test weld.