Phenolic rods are a hard, dense material made by applying heat and pressure to fiber or fabric and applying a synthetic resin. Phenolics are some of the best-known general purpose thermoset resins. It is lightweight, about half the weight of aluminum, and hasan unusual combination of desirable properties. This linen phenolic is a fine weave cotton fabric base phenolic laminate produced from cloth weighing less than 4 ounces per square yard, with a thread count of not less than140 total in both directions. It's incredibly strong and has great machining properties.