The next mechanical test performed was the Mandrel Bend Test, ASTM D522. This important stress test gives the design engineer a predictive indicator of a coatings performance. Original specimens of the Rust Bullet® panel (number 2), the Wasser® panel (number 6), and the POR-15® panel (number 8) were evaluated for flexibility of the coating in accordance with the procedures set forth in ASTM D522, method B. The panels were bent 180 degrees around a 3/8 inch steel mandrel and the condition of the coating at the “bend site” was visually examined and evaluated.

Results:

At a 12% elongation of the respective coatings, Wasser® Brand System (panel number 6), and POR-15® System (panel number 8) exhibited cracking of the film. At a 12% elongation of the coating Rust Bullet® (panel number 2) did not exhibit any cracking or disbonding of the film.

Printed from National Testing Standards, Inc., Report:
“Test No. 6:

Method: Original specimens of panels 2, 6, and 8 were evaluated for flexibility of the coating in accordance with the procedures set forth in ASTM D-522 method B using a 3/8” mandrel.
Results: At a 12% elongation of the respective coatings, panels 6 and 8 exhibited cracking of the film. At a 12% elongation of the coating panel 2 did not exhibited any cracking or disbonding of the film.”

(Report No.27935R2 National Testing Standards, Inc.)