Weld-Through Primer Guidelines: General Motors - UPDATE

Posted on 02 May 2025 Print

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.

GM calls out the use of weld-through primer within procedures and multiple documents:

  • GM-approved weld-though primers are found in the vehicle-specific body repair manual (BRM) under: Body Repair ➤ Paint And Coatings ➤ Introduction ➤ Anti-Corrosion Treatment and Repair.
  • GM recommends 3M 05917, Transtar 4353, or equivalent weld-through primer.
  • MIG Welded Full Panel Replacement and Resistance Spot Welded Full Panel Replacement documents:
    • Found in vehicle-specific BRMs under: Body Repair ➤ Collision Repair ➤ Repair Instructions
    • "Apply GM-approved Weld-Thru Coating or equivalent to all mating surfaces."

Always use vehicle-specific body repair manuals to determine which type of welding is required for the repair you are performing. Failure to follow OEM procedures sacrifices 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

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