Weld-Through Primer Guidelines: General Motors

Weld-through primers are generally a zinc-based product that are applied to the mating surfaces prior to welding. Corroding zinc forms zinc oxide which protects the steel. This is called sacrificial corrosion. For a quality weld to be made it’s required that the weld-through primer be removed from the direct weld zone before welding the joint when GMA welding. Many OEMs have a position on when and how to use weld-through primer or when it shouldn’t be utilized. Let’s see what General Motors (GM) recommends and where this information can be found.

Weld-though primer recommendations can be found at www.gmparts.com under: Technical Resources ➤ Technical Documents ➤ Anti-Corrosion Treatment and Repair.

• GM recommends the use of weld-through primer to all mating surfaces for squeeze-type resistance spot welding (STRSW).
• GM recommends the use of weld-through primer on all mating surfaces for GMA welding.
• GM has an approved weld-through primer with a part number of 4353 with a disclaimer “*We believe these sources and their products to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from these firms or for any such items which may be available from other sources.”
• Per GM, on vehicles with mixed materials, most mating surfaces are rivet bonded so weld-through primer is not used.

Use the vehicle-specific body repair manuals to determine which type of welding is required for the repair you are performing. Failure to follow OEM procedures will sacrifice the safety and quality of the repair.

For additional GM information, check out the following pages:
Chevrolet OEM Information
GMC OEM Information
Buick OEM Information
Cadillac OEM Information

Additional I-CAR Collision Repair News you may find helpful:

• Collision Information Website Access: General Motors
• Step-By-Step: Accessing General Motors Repair Information
• Weld-Through Primer Guidelines
• Welding And MIG Brazing Hotspot

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