PX521
also PMMA-like Casting Resin
PX521 is a vendor-coded, UV-stabilized methacrylate (PMMA-type) casting resin/cast plate system: a low-viscosity MMA/pre-polymer syrup that is bulk-polymerized in a mould or between glass plates to give a fully amorphous, glass-clear thermoset-like acrylic body.
Values for the UV Resistant condition
PX521 grades and fills
PX521 is supplied in 6 conditions, soft to hard. UV Resistant is the default FabDigit quotes; the values on this page are for it.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Flame-retardant (high ATH loading) casting grade | Specify for transport interiors, building panels and enclosures needing low flame spread/smoke from an acrylic casting. | 34 | 0.6 | 92 Shore D | |
Mineral (ATH) filled solid-surface casting grade | Choose for cast worktops, sinks and sanitary ware where thickness, stiffness, thermal stability and repairable matte surfaces matter more than clarity. | 40 | 0.7 | 98 HRM | |
Impact-modified (rubber-toughened) casting grade | Use where edge chipping, drilling near edges or vandal/impact loads would crack standard cast acrylic. | 52 | 25 | 70 HRM | |
Low-exotherm embedding / encapsulation casting grade | Pick for thick-section embedments (specimens, trophies, decorative inclusions) where cure exotherm and shrink cracking must be controlled. | 62 | 5 | 85 Shore D | |
Pigmented / opaque & translucent colour casting grade | Use for coloured signage faces, diffusers and decorative cast parts where light level or opacity is tuned by pigment. | 70 | 3.5 | 88 Shore D | |
UV ResistantDefault UV-stabilized clear casting grade (default) | Default choice for outdoor signage, glazing, lenses and displays needing long-term non-yellowing clarity. | 72 | 4 | 95 HRM |
Supply forms, finishes and certifications
Ways PX521 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
OPT | Optical/low-haze casting grade | Grade option |
What is PX521?
PX521 is a vendor-coded, UV-stabilized methacrylate (PMMA-type) casting resin/cast plate system: a low-viscosity MMA/pre-polymer syrup that is bulk-polymerized in a mould or between glass plates to give a fully amorphous, glass-clear thermoset-like acrylic body. It is chosen for the best-in-class optical clarity (~92 % transmission), non-yellowing outdoor life, deep-section castability and easy polishing/cementing typical of cast acrylic. Limits are notch brittleness (Izod ≈ 15–20 J/m), a service ceiling near 80 °C, attack by ketones/esters/chlorinated solvents and stress-crazing under solvent or alcohol exposure; because the designation is a proprietary product code, values below are typical cast-PMMA class data rather than a certified spec sheet. PX521 has a density of 1.19 g/cm³ (0.043 lb/in³), heavier than 53% of polymer grades. Its glass-transition temperature is 110°C (230 °F). PX521 has a tensile strength of 72 MPa (10.4 ksi), stronger than 78% of polymer grades. Elongation at break is 4% and the elastic modulus is 3.2 GPa (0.464 Msi).
What is PX521 used for?
- Vacuum casting prototypes
- Clear industrial prototypes
- Lenses, light pipes and lighting covers
- Display and instrument windows
- Outdoor signage and glazing panels
- Flow-visualisation and fluid-path models
- Encapsulated and embedded-object parts
Advantages
- Polishes to a fine finish — 95/100, better than 98% of polymer grades
- Good UV / weathering resistance — 92/100, better than 93% of polymer grades
- Easy to machine — 75/100, better than 78% of polymer grades
- Stiff — 3.2 GPa (0.464 Msi), better than 77% of polymer grades
Limitations
- Low fracture toughness — 1.1 MPa·√m (1 ksi·√in), worse than 82% of polymer grades
- Limited ductility — 4%, worse than 78% of polymer grades
- Needs corrosion protection — 70/100, worse than 78% of polymer grades
PX521 properties
Typical room-temperature values for PX521-UV Resistant; bars are the position among polymer grades.
Physical6
PX521 has a density of 1.19 g/cm³ (0.043 lb/in³), heavier than 53% of polymer grades. Its glass-transition temperature is 110°C (230 °F).
Mechanical15
PX521 has a tensile strength of 72 MPa (10.4 ksi), stronger than 78% of polymer grades. Elongation at break is 4% and the elastic modulus is 3.2 GPa (0.464 Msi).
Thermal11
PX521 is rated for continuous service to 80°C (176 °F). It conducts heat at 0.19 W/m·K (0.11 BTU/hr·ft·°F), worse than 68% of polymer grades. Thermal expansion is 70 µm/m·K (38.9 µin/in·°F).
Electrical7
PX521 is an electrical insulator with a dielectric strength of 30 kV/mm (762 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 78% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of PX521 takes about 100 MJ of energy and emits 6.5 kg of CO₂ — less than 61% of polymer grades. Typical recycled content is 5%.
Manufacturability4
PX521's machinability is very good (75/100, better than 78% of polymer grades); weldability poor (30/100); formability good (60/100).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. PX521 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PX521
Is PX521 easy to machine?
Machines cleanly with sharp carbide, high speed/low feed, 0° to slightly positive rake and air or mist cooling; anneal 2–4 h at 75–80 °C before and after heavy cuts to avoid crazing, and avoid coolant with alcohols.
Can PX521 be welded?
Not thermally welded in practice — join with MMA/solvent cement (acrylic dichloromethane or two-part methacrylate adhesive) for optically clear, near-parent-strength bonds; UV-cure acrylic adhesives for clear glazing joints.
Can PX521 be formed, bent or molded?
Cast between silicone/glass tooling at 40–70 °C with post-cure to 90–110 °C; thick sections need slow ramped cure to control exotherm and shrink voids, and finished plate thermoforms at 150–170 °C.
Manufacturability
The process limits FabDigit's quote engine applies to PX521. Design inside these and the part quotes instantly; outside them it routes to an engineer.
Injection molding
| Mold shrinkage | — |
|---|---|
| Wall thickness | — – — |
| Recommended draft | — |
| Pre-drying | — |
3D printing
| Technologies | SLA |
|---|---|
| Layer height | 50 – 300 µmdefault 100 µm |
| Minimum wall / feature | 1 / 0.5 mm |
| Build envelope | 300 × 300 × 380 mm |
| Supports | Yes |
| Anisotropy | Moderate |
PX521 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| crosslinker (glycol dimethacrylate type)raises solvent and heat resistance of the casting | 0 – 2 | 0.5 |
| peroxide initiator (e.g. dibenzoyl/peroxcure package; sometimes with amine/redox accelerator | 0.05 – 0.6 | 0.25 |
| UV absorber / HALS stabilizerbenzotriazole-type; source of the UV-Resistant designation | 0.1 – 1 | 0.4 |
| release / flow / defoaming additives | 0 – 0.5 | 0.15 |
| alumina trihydrate (ATH) filleronly in MF / FR solid-surface variants (typ. 55–62 wt %) | 0 – 65 | 0 |
| methyl methacrylate (MMA) monomer + PMMAbulk-polymerized in mould; residual monomer typically <1 % after full cure | ≥ 92 (balance) |
What surface finishes work on PX521?
Sand progressively then flame-, diamond- or buff-polish to optical clarity; accepts hard-coat/anti-scratch and anti-reflective coatings, screen printing and acrylic-compatible paints — mask edges from solvent-based cleaners.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Coating
Injection Molding Coating
Metallization / Functional
Coloring
Equivalent designations
Standards and trade names that resolve to PX521 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- PMMA-like Casting Resin
How much does PX521 cost?
PX521 is a standard-cost polymer ($$), cheaper than about 59% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PX521 — frequently asked
What is PX521 used for?
PX521 is typically used for vacuum casting prototypes, clear industrial prototypes, lenses, light pipes and lighting covers, display and instrument windows, outdoor signage and glazing panels and flow-visualisation and fluid-path models. In short: UV-stable outdoor resin.
What is the tensile strength of PX521?
PX521 has a typical tensile strength of 72 MPa (10.4 ksi) — stronger than 78% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is PX521 easy to machine?
Yes — machinability is rated very good (75/100, better than 78% of polymer grades). Machines cleanly with sharp carbide, high speed/low feed, 0° to slightly positive rake and air or mist cooling; anneal 2–4 h at 75–80 °C before and after heavy cuts to avoid crazing, and avoid coolant with alcohols.
Can PX521 be welded?
Not readily — weldability is rated poor (30/100). Not thermally welded in practice — join with MMA/solvent cement (acrylic dichloromethane or two-part methacrylate adhesive) for optically clear, near-parent-strength bonds; UV-cure acrylic adhesives for clear glazing joints.
What surface finishes work on PX521?
Sand progressively then flame-, diamond- or buff-polish to optical clarity; accepts hard-coat/anti-scratch and anti-reflective coatings, screen printing and acrylic-compatible paints — mask edges from solvent-based cleaners.
Can PX521 be formed, bent or molded?
Cast between silicone/glass tooling at 40–70 °C with post-cure to 90–110 °C; thick sections need slow ramped cure to control exotherm and shrink voids, and finished plate thermoforms at 150–170 °C.
What is the maximum service temperature of PX521?
PX521 is rated for continuous use to about 80°C (176 °F), and briefly to 95°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PX521 cost?
PX521 is a standard-cost polymer ($$), cheaper than about 59% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in PX521?
Yes — PX521 is available for injection molding and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Engineered Materials Handbook Vol. 2: Engineering Plastics (PMMA section) — ASM International (1988)
- CAMPUS plastics database — PMMA cast/moulding grades typical values — CWFG / CAMPUS consortium (2024)
- ISO 7823-1 Cast poly(methyl methacrylate) sheets — requirements and test methods — ISO (2003)
- ASTM D4802 Poly(methyl methacrylate) Acrylic Plastic Sheet — ASTM International (2021)
- Cast acrylic sheet & casting-resin technical data (clear, impact-modified, mineral-filled solid surface) — Acrylic sheet/resin producers (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.