Measure what you see.
Operating Instructions PF-1412 BYK - Gardner USA 9104 Guilford Road Columbia, MD 21046 USA Phone 800-343-7721 301-483-6500 Fax 800-394-8215 301-483-6555 www.byk.com/instruments BYK-Gardner GmbH Lausitzer Str. 8 D-82538 Geretsried Germany Tel.
Description Description When a coated panel is bent tightly around a cylinder of known diameter, the damage caused by distending the coating may be evaluated. Panels of a variety of flexible materials, including steel to 1/32“ thick, may be used with the BYKGardner Mandrel Set. After bending the coated panel, the flexibility of the coating is indicated by the nature and extent of cracking and flaking and the radius of curvature required to produce these flaws.
General Information General Information The BYK-Gardner Mandrel Set is described in ASTM D522 „Test Methods for Mandrel Bend Test of Attached Organic Coatings“. The BYK-Gardner Mandrel Set has nine stainless steel rods of the following diameters: 1“, 3/4“, 1/2“, 7/16“, 3/8“, 5/16“, 1/4“, 3/16“, 1/8“. The rigid black anodized aluminum frame has slots in its base for holding rods not in use and „V“ shaped cuts at its top for supporting a mandrel in use.
Operation Operation A mandrel rod is simply placed in position in cuts at the top of the frame and then the test panel is folded tightly around the rod, coated face upward and outward. The coating may be examined for cracking, flaking and other types of damage caused by elongation. Various samples may be bent on one specified rod as a standard „pass or fail“ test or rods of decreasing diameter may be used with one type of test coating to learn what degree of elongation first produces failures in the coating.
Theory Theory When a test panel of known uniform thickness is bent closely around a mandrel of known diameter, the THEORETICAL change in length of the faces of the panel may be calculated. After bending, the outer curved surface will have been stretched a certain amount, the inner surface compressed an equal amount, and a plane midway between these faces will have remained the same length.
Theory the surface against the mandrel as the diameter decreases. The material seems to be more readily stretched than compressed, therefore, the outer surface is extended a little more than would be theoretically anticipated.
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