3M™ Scotch-Weld™ Structural Adhesives Primer EC-3924B is a corrosion inhibiting adhesive primer. Our epoxy based, synthetic resin primer provides a high degree of protection against corrosive environments both inside and outside the adhesive bondline and is formulated for optimal performance when used with 250°F curable 3M™ Scotch-Weld™ Structural Adhesive Films.