Composite · Material guide
Get quotes for custom G10 and FR4 parts
G10 and FR4 are glass-epoxy laminates: strong for their weight, dimensionally stable, and among the best machinable electrical insulators. Upload your drawing and we'll source competitive quotes from qualified manufacturing partners.
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- Below marketplace & specialist pricing
- Composites-specialist shops only
- NEMA LI 1 / MIL-I-24768
- Flame-retardant (FR4)
- Dedicated dust extraction
Why specialists
Why G10 jobs go wrong at generalist shops
G10 and FR4 look like plastic to a shop that machines plastic every day. They are not. Three places that difference costs you — and what our network does instead.
Failure mode 01 — Silica dust
Glass dust is a health hazard
G10 and FR4 dust is silica-based, abrasive, and genuinely dangerous without proper extraction. Shops cutting it on the side without the right handling put operators at risk and produce drift from dulled tooling.
Failure mode 02 — Tool wear
Abrasive glass eats carbide fast
Standard carbide tooling dulls far quicker on G10 than on aluminum. Shops that do not change on a known schedule produce the first batch clean and the last batch out of tolerance. Our shops run diamond-coated tooling and track wear.
Failure mode 03 — Edge delamination
Wrong feeds split the laminate
Push the wrong feed rate and the glass fibers shred at the edge rather than shear cleanly — delamination, fiber pullout, uneven edge. Dialing feeds and climb direction for the specific grade is the difference between a clean part and a reject.
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 | 400-500 V/mil (perpendicular to laminate) |
| Flame rating | FR4: UL94 V-0; G10: not rated |
| 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.
Stock
Forms we machine it from
Sheet & plate
0.5-50 mm thickness. The dominant form for structural insulators and PCB-adjacent work.
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.
Pricing position
Where our pricing lands
We have benchmarked G10 and FR4 quotes across hobbyist shops, generalist marketplaces, specialist composite shops, and direct offshore. We come in below marketplace and specialist pricing on G10 and FR4 work — benchmarked across single-part insulators, multi-layer grip stacks, and production battery trays. Faster turnaround on known specs, and the finish quality off a shop that cuts G10 every day beats generalist CNC work every time.
Put us on the clockHow it works
From file to parts in hand
Four steps. We route G10 and FR4 only to shops with proper silica extraction and composites tooling — not optional.
- Step 1
Upload the file
STEP, IGES, DWG, DXF, or PDF. Call out tapped holes, inserts, grade, and color.
- Step 2
We quote in a day
A composites-trained engineer reviews. We flag anything that will delaminate at the edge before cutting.
- Step 3
Routed to the right shop
G10 and FR4 go only to shops with proper extraction and composites tooling. We vet for that.
- Step 4
Parts ship direct
You get tracking and photos. We handle QC and anything that goes sideways.
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. Spec FR4 anywhere a flame rating matters (battery packs, electronics enclosures, anything a UL inspector will see). Spec G10 for pure structural insulation where fire is not a concern — it is often slightly stiffer and sometimes cheaper.
Get G10 / FR4 part quotes
Upload your drawing and we'll source competitive quotes from qualified manufacturing partners that machine and cut glass-epoxy laminate.
STEP · STL · IGES · DWG · DXF · PDF · and more
Uploads are secure & confidential