The BGD 568 T-Bend Tester is specifically designed for assessing the flexibility and adhesion of organic coatings on metallic substrates. This evaluation is carried out by observing the occurrence of cracking or loss of adhesion when a coated test panel undergoes bending. The method is instrumental in verifying whether paints, varnishes, or related products meet specific test requirements through a pass/fail assessment. Additionally, it aids in determining the minimum bending diameter at which cracking does not occur.
The testing process involves bending coated panels back on themselves to 180º, with the coated surface on the outer side of the bend. This is done at progressively less severe radii of curvature, with the radii defined by spacers or mandrels. After the bending process, each panel is carefully examined with a magnifying glass to detect any coating cracking. Additionally, a tape pull-off test is performed to assess the adhesion of the coating. The T-bend rating is established as the minimum diameter to which the test panel can be bent without experiencing cracking or loss of adhesion.
Standards
DIN EN ISO 17132
ASTM D 4145
EN 13523-7 - Paints and varnishes - T-bend test “Folding method”
