This machine measures wear by standard abrasive filled wheels, and measures resistance to scratching under a known load. 100 Initial Caliper Thickness swelling is critical where hardboard is subjected to large variations in humidity or long exposure to high humidity or water. Impact Strength under sudden localized load applied against the face of a panel held between supports. This value is usually determined by dropping a 2-inch diameter steel ball from increasing heights at the same point, the center, in the panel, until the panel fails. The height of drop in inches that produces visible failure on the opposite face is recorded as the index of resistance to impact.
Tensile strength is the resistance of a material to being pulled apart laterally.
Bond strength is the force that it takes to pull a material apart in a direction perpendicular to its surface. Products with high bond strengths are manufactured for specific uses. Breaking load, lbs. Modules of elasticity is a test of hardboard's ability to resist bending. It is determined by applying a known concentrated load mid-way between two supports and measuring the deflection that occurs.