U-Pol Weld #2 Weld Through Primer - 450ml. This primer allows for quick and easy professional-looking, permanent repairs. It provides a clean base for painting and is highly effective at conducting electricity, making it ideal for welding. It leaves a highly rust-resistant finish on all Spot, MIG, and TIG welds. Offers the best rust protection for welding applications, features high adhesion, and a fast-drying formula with a high concentration of metal for convenient and efficient use.