What is Linen Electrical Phenolic material?
Linen electrical phenolic is a composite material widely used by industries that make electrical products. Known as NEMA grade LE, or by its military specification MIL-I-24768/13, it is made of layers of fine-weave cotton linen cloth impregnated with phenolic resin and cured under high temperature and pressure. Many buyers know it as linen Micarta®, after the brand name that became shorthand for canvas and linen phenolic laminates. On our linen phenolic page you will find the sizes, colors and datasheets for both linen grades.
Properties of LE
LE has good electrical insulation properties, with high dielectric strength and low dielectric loss, so it resists the flow of current even at high voltages. Per NEMA, on 0.500-inch sheet, LE carries a minimum breakdown voltage of 40 kV and a maximum water absorption of 0.70%.
Like many of our other phenolics, LE has high compressive, tensile and flexural strength. It combines that with a fine surface and dense structure, so it holds tight tolerances and small details that coarser laminates cannot.
For machinists, LE is a good choice for custom parts. Because it is built on a fine linen weave rather than canvas or glass, it is one of the easier laminates to turn into custom machined parts with clean edges.
LE vs L vs Canvas Phenolic
Linen phenolic comes in two grades, and canvas phenolic is its coarser sibling:
- L (MIL-I-24768/15) is the mechanical grade: fine-weave linen for machined parts that need a fine edge and good appearance.
- LE (MIL-I-24768/13) is the electrical grade: the same fine weave with better moisture resistance and electrical properties, for parts that must insulate as well as hold a dimension.
- Canvas C and CE use a heavier cotton canvas. They are tougher in impact but machine to a rougher edge, so linen is the choice when detail matters.
If you are weighing linen Micarta against glass-epoxy for a handle or insulator, our G-10 vs Micarta comparison sets the NEMA figures side by side.
Uses of LE
Because of these properties, MIL-I-24768/13 linen phenolic is a versatile composite used in several different applications:
Gears, Bearings, Bushings, and Other Industrial Parts
- Parts where strength and resistance to wear matter, and where a fine machined finish is needed.
Electrical Insulators and Terminal Boards
- Insulating parts in electrical equipment, where LE's moisture resistance keeps its electrical properties stable in humid conditions.
Tool and Knife Handles
- Handles for industrial tools that see repeated impacts and shocks, and knife scales, where linen Micarta's fine texture and warm feel are prized.
How LE is made
LE starts with a fine-weave linen fabric, checked to be clean and free of contaminants. The fabric is impregnated with a phenolic resin and hardening agent, dried to a prepreg, stacked and pressed under heat and pressure, which cures the resin through the cloth. The cured laminate is then cut to size with a smooth, uniform finish. The result is durable electrical insulation that is ready for your industry. We make it as sheet, rod and tube.
Machining LE
Many of our phenolics are easy to machine, but the material is abrasive, so the right tools and technique give the best results:
- Keep your tools sharp so the material cuts cleanly and efficiently.
- Use moderate cutting speeds to avoid localized heat buildup, which can scorch or chip the edge.
- Consider a water-soluble coolant to flush away debris and prevent heat buildup.
- Hold the material tightly in your fixture so it stays stable and secure.
- Always use personal protective equipment when working with materials that produce dust and debris: eye and hearing protection, gloves and, where needed, a respirator.
The same techniques apply to the other laminates; our guide to machining G-10 covers tooling in more detail.