Ready Plastics

NEMA & Engineering Plastic Grades Directory

This directory lists every grade page in the Ready Plastics grades cluster, organized by parent material family. Use it to find the right NEMA designation, understand how grades differ within a family, and navigate to detailed specification pages.

Each grade page covers: chemistry, key properties, standard sizes, applicable standards (NEMA LI 1, MIL-I-24768, ASTM D709), comparison to neighbor grades, and a quote CTA.

Paper Phenolic Grades

Paper phenolic laminates are built from kraft paper saturated with phenolic resin. The NEMA grade designates whether the laminate is optimized for mechanical service, electrical insulation, or punch-press production.

GradeURLPrimary useMIL spec
NEMA XX/resources/grades/xx/Mechanical — gears, spacers, jigsMIL-I-24768/11
NEMA XXX/resources/grades/xxx/Electrical insulation — terminal boards, panelsMIL-I-24768/13
NEMA XXX-P/resources/grades/xxxp/Hot-punch production — terminal boardsMIL-I-24768/15
NEMA XXX-PC/resources/grades/xxxpc/Cold-punch production — terminal boards, gasketsMIL-I-24768/16

Parent material: Paper Phenolic

Cotton/Canvas Phenolic Grades

Canvas phenolic laminates use woven cotton canvas reinforcement instead of paper, delivering higher impact strength and toughness. Two primary NEMA grades:

GradeURLPrimary useMIL spec
NEMA C/resources/grades/c/Mechanical — gears, bushings, wear partsMIL-I-24768/3
NEMA CE/resources/grades/ce/Electrical + mechanical — switchgear panels, motor brush holdersMIL-I-24768/4

Parent material: Canvas Phenolic

Linen Phenolic Grades

Linen phenolic uses fine-weave linen or linen/cotton blend fabric, producing a smoother machined surface than canvas phenolic. Two primary NEMA grades:

GradeURLPrimary useMIL spec
NEMA L/resources/grades/l/Fine-tolerance mechanical — instrument gears, precision bushingsMIL-I-24768/5
NEMA LE/resources/grades/le/Electrical + fine finish — coil forms, relay insulatorsMIL-I-24768/6

Parent material: Linen Phenolic

Glass-Fabric Phenolic and Thermoset Grades

Glass-reinforced laminates use woven E-glass cloth as reinforcement. The resin determines the grade: phenolic (G3), melamine (G5, G9), silicone (G7), or epoxy (G10, G11, FR4, FR5). These grades span electrical insulation from 250°F to 425°F continuous service.

GradeURLResinKey differentiatorMIL spec
NEMA G3/resources/grades/g3/PhenolicFoundational glass phenolic; lowest costMIL-I-24768/1
NEMA G5/resources/grades/g5/MelamineHigher arc resistance than G3MIL-I-24768/9
NEMA G7/resources/grades/g7/Silicone425°F continuous; Class H insulationMIL-I-24768/17
NEMA G9/resources/grades/g9/MelamineArc resistance >120 s (ASTM D495)MIL-I-24768/2
NEMA G11/resources/grades/g11/High-Tg Epoxy285°F; Tg ~170°C; non-FRMIL-I-24768/18

Parent material: Glass Phenolic | Glass-Silicone | Glass-Melamine

Glass-Epoxy Grades (G10 / FR4 Family)

G10 and FR4 are the dominant glass-epoxy laminates. They share identical glass reinforcement and similar epoxy chemistry — the critical difference is flame retardancy.

GradeURLFlame retardantTgKey use
NEMA G10/resources/grades/g10/No~130°CIndustrial glass-epoxy; no FR requirement
NEMA FR4/resources/grades/fr4/Yes (V-0)~130–140°CUL-listed panels, PCB substrate, FR-required
NEMA G11/resources/grades/g11/No~170°CHigh-temp; G10 upgrade for 285°F service
NEMA FR5/resources/grades/fr5/Yes (V-0)~170°CHigh-temp + FR; FR4 upgrade for 285°F service

G10 ≠ FR4. FR4 has brominated flame-retardant chemistry (UL94 V-0); G10 does not. Never specify one in place of the other without checking your compliance requirement.

Material hubs: G10 | FR4 Comparison: G10 vs. FR4

Polyester Glass Mat Grades

GPO-3 is a glass-mat (not woven-cloth) reinforced polyester thermoset — the dominant arc-resistant, flame-retardant insulation laminate in North American switchgear.

GradeURLArc resistanceFlame retardantKey use
GPO-3/resources/grades/gpo-3/≥180 sYes (V-0)Switchgear barriers, bus bar supports, arc chutes

Acetal Copolymer Grades and Brands

Acetal copolymer (POM-C) stock shapes are sold under multiple brand names. These grade pages cover the two major commercial acetal copolymer brands and distinguish them from acetal homopolymer (Delrin).

Grade/BrandURLManufacturerNotes
Celcon/resources/grades/celcon/CelaneseUS-primary brand; FDA grades available
Hostaform/resources/grades/hostaform/Celanese (fmr. Ticona)European-heritage brand; ISO-standard data; EU food contact grades

Acetal copolymer ≠ Delrin (acetal homopolymer). Delrin is DuPont's acetal homopolymer (POM-H) — higher room-temperature stiffness. Celcon and Hostaform are POM-C copolymer — better hot-water resistance, no centerline porosity in large rod. See Delrin vs. Acetal Copolymer.

Parent material: Acetal Copolymer | Delrin (Homopolymer)

Quick-Reference Grade Selector

Use this table to find the right grade for a given requirement:

If you need…Grade
Lowest-cost paper phenolic mechanical stockXX
Electrical insulation in a paper phenolicXXX
Hot-punch terminal board productionXXX-P
Cold-punch terminal board productionXXX-PC
High-impact canvas phenolic for gearsC
Canvas phenolic with electrical insulationCE
Fine-finish linen phenolic, mechanicalL
Fine-finish linen phenolic, electricalLE
Glass-reinforced laminate, 250°F, lowest costG3
Glass-reinforced, arc resistant, 250°FG5 or G9
Arc resistance >120 s (ASTM D495)G9
Glass-reinforced, 425°F continuousG7
Glass-epoxy, non-FR, 266°FG10
Glass-epoxy, flame-retardant (V-0), 266°FFR4
Glass-epoxy, non-FR, 285°F (high-Tg)G11
Glass-epoxy, flame-retardant, 285°F (high-Tg)FR5
Arc-resistant, V-0, switchgear barriersGPO-3
Acetal copolymer, US supply chainCelcon
Acetal copolymer, European/ISO specHostaform

Standards at a Glance

All NEMA thermoset laminates are governed by three core standards:

  • NEMA LI 1 — National Electrical Manufacturers Association's laminated insulation standard. Defines grades, property minimums, and test sequences.
  • ASTM D709 — ASTM International's Standard Specification for Laminated Thermosetting Materials. Provides test methods referenced in NEMA LI 1.
  • MIL-I-24768 — U.S. military laminate specification with numbered sub-specifications per grade. Required for defense procurement programs.

Supplemental standards:

  • IEC 60893 — International equivalent, used in European and IEC-standard equipment
  • UL 94 — flammability classification (V-0, V-1, V-2, HB) referenced for FR4, FR5, GPO-3
  • ASTM D495 — arc resistance test (critical for G9, GPO-3)

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Material hubs

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All Grades

NEMA CENEMA CE is the electrical-grade canvas phenolic laminate — woven cotton canvas and phenolic resin delivering combined high impact strength and electrical insulation. Target: 'ce phenolic' (vol 30, KD 0).NEMA FR4NEMA FR4 is the flame-retardant glass-cloth epoxy laminate — UL94 V-0 rated, the dominant PCB substrate material and a standard industrial electrical insulation laminate. This spec page focuses on the NEMA LI 1 FR4 grade definition; for the practical buying guide see the FR4 material hub.NEMA XXX-PCNEMA XXX-PC is the cold-punch paper phenolic grade — formulated to punch cleanly at room temperature without pre-heating, combining electrical insulation with cold-press production efficiency.NEMA LENEMA LE is the electrical-grade linen phenolic laminate — fine-weave linen fabric and phenolic resin with tighter electrical controls than Grade L, delivering smooth machined surfaces plus reliable electrical insulation. Target: 'le phenolic' (vol 50, KD 0).GPO-3GPO-3 is a polyester-resin, glass-mat-reinforced thermoset laminate rated for arc resistance, flame retardancy, and electrical insulation — a cost-effective alternative to phenolic glass laminates in switchgear and electrical enclosure applications. Target: 'gpo-3' (vol 150, KD 2).NEMA XXXNEMA XXX is the electrical-grade paper phenolic laminate — higher purity kraft paper and tighter phenolic resin controls deliver improved dielectric strength and insulation resistance over NEMA XX.NEMA G3NEMA G3 is the foundational glass-fabric phenolic laminate — woven E-glass cloth and phenolic resin delivering higher strength and dielectric performance than fabric or paper phenolics at a lower cost than G10 or epoxy grades.NEMA G10NEMA G10 glass-epoxy laminate guide: properties, grades, machining, applications, and forms. Distinct from FR4.NEMA G7NEMA G7 is the high-temperature glass-cloth silicone laminate rated to 425°F (218°C) continuous service — the benchmark thermoset for transformer coil forms, high-voltage bushings, and dry-type transformer insulation. MIL-I-24768/17.NEMA CNEMA C is the canvas phenolic mechanical grade — woven cotton canvas saturated with phenolic resin for superior impact strength, machinability, and wear resistance in mechanical applications.HostaformHostaform is Ticona (now Celanese)'s European-origin brand of acetal copolymer (POM-C) — widely specified in European industrial standards and available globally as molding resin and stock shapes. Target: 'hostaform' (vol 80, KD 0).NEMA XXX-PNEMA XXX-P is the post-formable paper phenolic grade — modified resin system allows hot punching and forming without cracking. Key for high-volume terminal board and panel production.NEMA LNEMA L is the fine-weave linen phenolic mechanical grade — a tighter-woven fabric than canvas phenolic delivers a smoother machined surface, finer tolerances, and better surface quality for precision mechanical parts.CelconCelcon is Celanese's brand name for acetal copolymer (POM-C) resin and stock shapes — a leading grade of acetal copolymer with excellent dimensional stability, chemical resistance, and low friction. Target: 'celcon' (vol 150, KD 1).NEMA G9NEMA G9 is the arc-resistance-optimized glass-cloth melamine laminate — woven E-glass and melamine resin delivers arc resistance >120 seconds (ASTM D495), the highest arc rating in the standard NEMA glass-laminate family. MIL-I-24768/2.NEMA G5NEMA G5 is the glass-fabric melamine phenolic laminate — woven E-glass cloth with melamine resin delivers higher arc resistance than G3 phenolic while operating in the same 250°F temperature envelope.NEMA G11NEMA G11 is the high-temperature glass-epoxy laminate — same woven E-glass reinforcement as G10 but with a higher-Tg epoxy resin system rated to 285°F continuous, retaining mechanical and electrical properties at elevated temperature where G10 softens.NEMA FR5NEMA FR5 is the high-temperature flame-retardant glass-epoxy laminate — a higher-Tg, UL94 V-0 rated alternative to FR4 for applications demanding both flame retardancy and elevated temperature performance above 285°F. Target: 'FR5' (vol 250, KD 0).NEMA XXNEMA XX is a paper-base phenolic laminate grade engineered for general-purpose mechanical applications. Learn its properties, standards, sizes, and how it compares to XXX and XXX-P.