ASTM International Standard Test Method for Pressure Mottling and Blocking Resistance of Organic Coatings on Metal Substrates ASTM D3003-26

This test method covers the procedures for determining the pressure mottling and sticking, or blocking resistance of organic coatings applied on coil-coated or factory coated metal substrates prior to fabrication. The coated metal is cut into at least four, preferably six, suitably-sized panels which are then subjected to a specified pressure and temperature for a specified time. After the heat is turned off and the specimen cooled, the samples are examined for any signs of sticking or blocking and mottling.