Weld-Through Primer Guidelines: Toyota/Lexus/Scion

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 Toyota/Lexus/Scion recommends and where this information can be found.

This information can be found in the vehicle-specific body repair manual in the Precautions for Welding document, under the General tab. Toyota/Lexus/Scion:

  • Requires the application of weld-through primer to the contact surfaces of welding areas.
  • Warns not to apply weld-through primer outside of the contact surfaces.
  • Does not recommend a specific weld-through primer product or part number.

The Toyota/Lexus/Scion publication, Collision Pros - Winter 2015 (Issue 1) edition, has an article regarding weld-through primer usage. The article states "When using weld-through primers, keep in mind that zinc-based primers are a more suitable material to use than copper-based primers."

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 Toyota/Lexus/Scion information, check out the following pages:
Toyota OEM Information
Lexus OEM Information
Scion OEM Information

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