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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 Honda/Acura recommends and where this information can be found.
Honda/Acura has two publications in their Body Repair News titled Honda Body Repair Manual Welding & Sectioning Guideline Revisions and Acura Body Repair Manual Welding & Sectioning Guideline Revisions. The guidelines for both recommend the use of weld-through primer for certain applications and advises against it for others. Per the Honda Body Repair Manual Welding & Sectioning Guideline Revisions:
- “When doing squeeze-type resistance spot welding (STRSW), apply a zinc-rich weld-through primer, or spot sealer, to bare steel areas being welded and wipe off any excess. Use approved respiratory protection when working around these primers.
- Weld-through primer should never be used when doing MAG plug, MAG butt, or MIG brazing. Studies have shown that weld-through primers can negatively affect weld or joint quality.
- When doing MAG plug and butt welding, or MIG brazing, remove only enough of the factory e-coat to allow bare metal in the weld or joint area. Then, apply epoxy primer over the completed weld or joint, including all exposed steel.”
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 sacrifices the safety and quality of the repair.
For additional Honda/Acura information, check out the following pages:
Honda OEM Information
Acura OEM Information
Additional I-CAR Collision Repair News you may find helpful:
- Step-By-Step: Accessing Honda And Acura Repair Information
- Weld-Through Primer Guidelines
- Welding And MIG Brazing Hotspot
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