Composite · Material guide
Custom G10 and FR4 parts from independent machine shops
G10 and FR4 are glass-epoxy laminates: strong for their weight, dimensionally stable, and among the best machinable electrical insulators. Upload a drawing and hear back from shops that cut and machine glass-epoxy sheet every day.
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G10 / FR4 shops on OpenSpindle
Real shops that machine and cut glass-epoxy laminate. See their equipment and talk to the person making your part.
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Grades
G10 and FR4 grades shops run most
The grade sets flammability rating, temperature limit, and cost. These are the ones you will see quoted; if yours is not here, ask when you request a quote.
G10
The general-purpose high-strength grade. Glass-fabric-reinforced epoxy with excellent mechanical strength, dimensional stability, and electrical insulation. Machines cleanly and is stocked widely in sheet.
Best for Structural insulators, spacers, fixtures, general parts
FR4
The flame-retardant version of G10, rated UL94 V-0 (self-extinguishing). Mechanically and electrically very similar to G10 and is the standard PCB substrate. The default choice where flammability matters.
Best for PCB substrates, electrical panels, parts needing a flame rating
G11
A higher-temperature epoxy laminate that holds more of its strength at elevated temperature than G10. Costs more and is less commonly stocked, specified when service temperature runs high.
Best for Elevated-temperature insulators and structural parts
Garolite
A common trade name used interchangeably for G10 and FR4 glass-epoxy laminate. Not a separate material; the underlying grade is still G10 or FR4, so confirm which one your spec needs.
Best for Any G10 / FR4 application, under a different name
Specs
Material properties
Representative values for FR4 / G10 glass-epoxy laminate. Exact numbers vary by grade, resin, and glass content.
| Property | Typical value |
|---|---|
| Density | ~1.80 g/cm³ (0.065 lb/in³) |
| Tensile strength | ~35-45 ksi (240-310 MPa) |
| Flexural strength | ~50-70 ksi (345-480 MPa) |
| Max continuous service temp | ~130-140 °C (265-285 °F) for FR4 |
| Dielectric strength | Very high; excellent electrical insulator |
| Water absorption | Very low, ~0.1% |
| Machinability | Machines cleanly but highly abrasive; dulls tooling fast |
The glass fibers that make G10 and FR4 strong also make them abrasive, so shops run carbide or diamond tooling. The epoxy-glass dust is a respiratory and skin irritant, so parts are cut wet or with dust extraction.
Processes
Manufacturing methods for g10 / fr4
The right process depends on part geometry, tolerances, and production volume.
Finishing
Finishes for g10 / fr4
G10 and FR4 normally ship as-machined. There is no plating or anodize; finishing is about edge quality and handling.
As-machined
The standard state. The laminate is dense and stable straight off the machine, and is fine for insulators, spacers, and structural parts.
Sealed edges
Machined edges expose glass fibers and can wick moisture. Sealing the edges is used where the part sees humidity or fluids.
Color
G10 and FR4 come in natural (green, tan, or off-white). Color is inherent to the sheet, not applied, so specify the stock color if it matters.
G10 and FR4 should not be laser cut: the epoxy releases toxic fumes and chars the edge. Waterjet, machining, or routing are the preferred processes.
Applications
Where g10 / fr4 parts are used
G10 and FR4 show up wherever a part must be strong, stable, and electrically insulating at the same time.
Compare
G10 / FR4 vs other materials
How G10 / FR4 stacks up against the other composites and plastics shops quote most.
G10 / FR4 vs Carbon fiber
Carbon fiber →- Carbon fiber is stiffer and lighter for the same part
- G10 / FR4 is an electrical insulator, while carbon fiber is conductive
- G10 / FR4 costs much less and is easier to source in plain sheet
Choose G10 / FR4 for insulating, cost-sensitive parts. Choose carbon fiber when maximum stiffness-to-weight justifies the price and conductivity is acceptable.
G10 / FR4 vs Phenolic
Phenolic →- G10 / FR4 is stronger and holds up to higher temperature
- Phenolic machines more easily and has better wear and bearing performance
- Both are good electrical insulators; the glass-epoxy resists moisture better
Choose G10 / FR4 for strength and temperature. Choose phenolic for easier machining and wear surfaces such as bushings and gears.
Questions
Frequently asked questions
They are the same base material, a glass-fabric-reinforced epoxy laminate, with one difference: FR4 is flame-retardant and rated UL94 V-0 (self-extinguishing), while standard G10 is not. Their mechanical and electrical properties are nearly identical. Use FR4 when a flammability rating is required, such as in electronics, and G10 when it is not.
Get G10 / FR4 part quotes
Upload a drawing once and compare quotes from independent shops that machine and cut glass-epoxy laminate.
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