3M Resin Bond Hot Pressed Wheel 73HI is a conventional grinding wheel with white rods for slab grinding operations on a variety of substrates. The wheels feature zirconia grains and a resin bond.About Resin Bonds 3M Resin Bond Hot Pressed Wheel 73HI is a hot pressed wheel with a resin bond. Synthetic resin bonds consist of phenolic resins and various fillers that have a decisive influence on the bonding properties. Wheels with these bonds are less sensitive to sudden temperature changes, shock and impact than wheels with a vitrified bond. This particular grinding wheel is targeted for slab grinding operations on various materials, and features white rods and zirconia grains.