Phenolic Resin Laminate Garolite G-10 / FR4
Comprehensive technical specification for Garolite G-10 / FR4 phenolic resin laminate, covering Canadian stock sizes, machining parameters, common defects, and storage guidelines for fabrication and CNC operations.
Material Overview & Common Uses
Garolite G-10 (and its flame-retardant variant FR4) is a high-pressure thermoset phenolic resin laminate reinforced with continuous woven fiberglass cloth. It is widely used in electrical insulation, structural jigs, fixtures, and high-strength mechanical components. In Canadian fabrication shops, G-10/FR4 is common for CNC router tables, vacuum hold-down grids, electrical panel boards, and precision shims. Its high dimensional stability, low moisture absorption, and excellent dielectric properties make it a go-to for both electrical and mechanical applications. Typical thicknesses range from 0.8 mm (1/32") to 50 mm (2"), with standard sheet sizes of 48" x 96" (1220 mm x 2440 mm) and 36" x 48" (915 mm x 1220 mm).
Core Technical Properties & Sizing
| Property | Value / Specification |
|---|---|
| Density | 1.85 g/cm³ (0.067 lb/in³) |
| Tensile Strength (Lengthwise) | 310 MPa (45,000 psi) min per NEMA LI-1 |
| Flexural Strength (Lengthwise) | 415 MPa (60,000 psi) min |
| Compressive Strength (Flatwise) | 415 MPa (60,000 psi) min |
| Water Absorption (24h, 1/8" thick) | < 0.10% by weight |
| Continuous Operating Temperature | 130°C (266°F) G-10 / 140°C (284°F) FR4 |
| Flammability Rating | UL 94 V-0 (FR4 only) |
| Dielectric Strength (1/8" thick) | 500 V/mil (20 kV/mm) min |
| Standard Canadian Stock Sizes | 48" x 96" (1220 x 2440 mm) & 36" x 48" (915 x 1220 mm) |
| Thickness Tolerances (NEMA LI-1) | ±0.005" (1/16") up to ±0.030" (1"+) |
| Surface Finish | Glossy (standard) / Matte (optional) |
Machinability, Tooling & Feeds
| Parameter | Recommended Setting / Note |
|---|---|
| Tooling Material | Carbide (mandatory), PCD (recommended for high volume) |
| CNC Router Spindle Speed | 12,000 – 18,000 RPM |
| Feed Rate (1/4" bit) | 100 – 200 IPM |
| Feed Rate (1/2" bit) | 80 – 120 IPM |
| Depth of Cut per Pass | 0.020" – 0.060" (0.5 – 1.5 mm) |
| Milling Strategy | Climb milling (preferred to reduce edge fraying) |
| Drilling | Carbide bits, 118° point angle, peck drilling for deep holes |
| Coolant | Compressed air or mist (avoid water-based to prevent swelling) |
| Dust Extraction | HEPA vacuum + P100 respirator (fibreglass dust is a respiratory irritant) |
| Sawing | Carbide-tipped circular saw (60-80 teeth) or abrasive cut-off |
| Laser Cutting | NOT recommended (toxic fumes from phenolic resin and glass) |
Common Defects & Quality Control
| Defect / QC Check | Description / Acceptable Limit |
|---|---|
| Delamination | Separation of glass layers (white lines/bubbles) – Zero tolerance |
| Surface Pitting | Small voids from trapped air – rejects if electrically exposed |
| Warpage | Bow/twist exceeding 0.005" per linear foot |
| Edge Cracking | Micro-cracks from dull tooling or excessive feed rates |
| Thickness Variation | Out of tolerance per NEMA LI-1 grade |
| Contamination | Oil/grease spots affecting bonding or electrical properties |
| QC Inspection Method | 5-point micrometer check, feeler gauge flatness, visual inspection |
| Max Defect Rate (NEMA LI-1) | < 2% sheets with minor surface defects; 0% delamination/out-of-tolerance |
Storage, Handling & Racking Guidelines
Store Garolite G-10/FR4 sheets flat on a level rack or pallet to prevent warpage. Maximum stack height: 24" (600 mm) to avoid crushing bottom sheets. Keep in a dry, climate-controlled environment (40–60% RH, 15–25°C). Avoid direct sunlight and heat sources – prolonged UV exposure can degrade the resin. Do not store near open flames or high-temperature equipment (flammable resin). Handle with clean, dry gloves to avoid oil contamination. For long-term storage, wrap in polyethylene film or kraft paper to protect from dust and moisture. Use edge protectors when banding stacks. When cutting, support the sheet fully to prevent flexing and edge chipping. Dispose of scrap as industrial waste – do not burn (toxic fumes).