Rust Proofing Weld
Definition - What does Rust Proofing Weld mean?
Rust proofing of welds is a process intended to prevent corrosion and rusting of metal joints where two metal pieces are welded together. Rust proofing provides permanent corrosion protection on the inner edges of the welded metal pieces. The protection of the welded joints is achieved by applying suitable coatings or performing a surface finishing process on rough portions of the welds.
Corrosionpedia explains Rust Proofing Weld
When metal pieces are welded together there are portions (e.g., plug welds, lap joints) that become inaccessible for a proper application of primer, coating or surface finishing. The solution for making these portions is to spray a weldable primer over these surfaces, then weld, and then spray primer over the completed weld. This is completely rust proof because the weld pool itself will burn off a bit of protective paint around the weld. Seam sealer paint is applied to rust proof a lap joint.
In many cases zinc primer is applied on both faces of the plug weld, then seam sealer is sealed because it becomes easy to smooth into seams instead of the alternative, which is to smooth the seam by hand wearing gloves wetted with panel wipe, stone chipping the coated area, painting a top coat and finally applying wax protection for permanently rust proofing the weld.