Vespel SP-1 SP-1
Grade · default condition
SP-1 = unfilled polyimide
Pick the unfilled natural polyimide for electrical insulators, high-temperature structural gaskets and thermal barriers needing the highest toughness and no conductive filler.
Values for the SP-1 condition
Other Vespel SP-1 grades and fills
Vespel SP-1 is listed in 6 conditions; see the grade overview at Vespel SP-1.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
15 % graphite + 10 % PTFE | Use the 15 % graphite plus 10 % PTFE grade for dry-running, low-load, low-speed sliding parts (friction about 0.1–0.2); strength falls to 45 MPa and service to 260 °C. | — | 45 | 3.5 | 87 Shore D |
Graphite + PTFE, higher graphite loading | Pick for reciprocating seals and dry-rubbing contacts: it keeps the load capacity of the 40 % graphite grade while added PTFE cuts break-away friction, at 45 MPa tensile and 2.5 % elongation. | — | 45 | 2.5 | 88 Shore D |
40 % graphite filled | Choose for high-PV, high-temperature bearings and seal rings that need low thermal expansion and higher stiffness; the 40 % graphite loading leaves the lowest toughness at 52 MPa and 3 % elongation. | — | 52 | 3 | 89 Shore D |
15 % MoS₂ filled | Use in vacuum, extremely dry or inert atmospheres where graphite stops lubricating; the 15 % MoS₂ filler suits spacecraft mechanism bearings and bushings up to 260 °C service. | — | 52 | 3.5 | 89 Shore D |
15 % graphite filled | Choose the 15 % graphite filled grade for plain bearings, piston rings and seals: wear rate and friction drop well below unfilled, with 0.87 W/m·K and 288 °C service. | — | 66 | 4.5 | — |
SP-1DefaultThis page Unfilled polyimide | Pick the unfilled natural polyimide for electrical insulators, high-temperature structural gaskets and thermal barriers needing the highest toughness and no conductive filler. | — | 86 | 7.5 | 90 Shore D |
What is Vespel SP-1 SP-1?
Vespel SP-1 SP-1 is Vespel SP-1 in the SP-1 grade — pick the unfilled natural polyimide for electrical insulators, high-temperature structural gaskets and thermal barriers needing the highest toughness and no conductive filler. Vespel SP-1 SP-1 has a tensile strength of 86 MPa (12.5 ksi), stronger than 86% of polymer grades. Elongation at break is 7.5% and the elastic modulus is 2.5 GPa (0.363 Msi). Vespel SP-1 SP-1 has a density of 1.43 g/cm³ (0.0517 lb/in³), heavier than 84% of polymer grades. Its glass-transition temperature is 385°C (725 °F).
Advantages
- High service temperature — 260°C (500 °F), better than 97% of polymer grades
- Good UV / weathering resistance — 70/100, better than 83% of polymer grades
- Conducts heat well — 0.29 W/m·K (0.168 BTU/hr·ft·°F), better than 80% of polymer grades
Limitations
- High embodied carbon — 16 kg CO₂/kg, worse than 98% of polymer grades
- Difficult to weld — 5/100, worse than 89% of polymer grades
- Limited formability — 10/100, worse than 87% of polymer grades
- Heavy — 1.43 g/cm³ (0.0517 lb/in³), worse than 84% of polymer grades
Vespel SP-1 SP-1 properties
Typical room-temperature values for Vespel SP-1 SP-1; 21 are specific to this condition. Other listed values are Vespel SP-1 reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
Vespel SP-1 SP-1 has a density of 1.43 g/cm³ (0.0517 lb/in³), heavier than 84% of polymer grades. Its glass-transition temperature is 385°C (725 °F).
Mechanical12
Vespel SP-1 SP-1 has a tensile strength of 86 MPa (12.5 ksi), stronger than 86% of polymer grades. Elongation at break is 7.5% and the elastic modulus is 2.5 GPa (0.363 Msi).
Thermal9
Vespel SP-1 SP-1 is rated for continuous service to 260°C (500 °F). It conducts heat at 0.29 W/m·K (0.168 BTU/hr·ft·°F), better than 80% of polymer grades. Thermal expansion is 54 µm/m·K (30 µin/in·°F).
Electrical5
Vespel SP-1 SP-1 is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), worse than 52% of polymer grades. UV resistance is very good.
Sustainability3
Producing a kilogram of Vespel SP-1 SP-1 takes about 300 MJ of energy and emits 16 kg of CO₂ — more than 97% of polymer grades. Typical recycled content is 0%.
Manufacturability4
Vespel SP-1 SP-1's machinability is good (55/100, worse than 64% of polymer grades); weldability not recommended (5/100); formability not recommended (10/100).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Vespel SP-1 SP-1
Is Vespel SP-1 easy to machine?
Cut dry at high speed with light feeds using sharp uncoated carbide; the material is dimensionally stable but swells with moisture pickup, and dust extraction is required. It grinds and bores to very high accuracy.
Can Vespel SP-1 be welded?
Non-melting material; it cannot be welded. Join with high-temperature epoxy or polyimide adhesives, or by mechanical fastening.
Can Vespel SP-1 be formed, bent or molded?
Cannot be injection moulded or thermoformed. Blanks and shapes are direct-formed from powder by high-temperature, high-pressure sintering and then machined to the finished part.
What surface finishes work on Vespel SP-1?
Normally used as-machined or ground; polishing produces low-roughness sealing faces. Surfaces can be plasma-activated before bonding, but the material cannot be plated.
Vespel SP-1 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.
| Element | Spec limit (wt %) |
|---|---|
| graphite15–40 wt% in SP-21/SP-211/SP-22 variants | ≈ 0 |
| PTFEabout 10 wt% in SP-211/SP-221 variants | ≈ 0 |
| MoS2about 15 wt% in SP-3 variant | ≈ 0 |
| polyimide (PMDA/ODA polymer)PMDA + 4,4'-oxydianiline polycondensate, unfilled | ≥ 100 (balance) |
Vespel SP-1 SP-1 — frequently asked
What is Vespel SP-1 SP-1 used for?
Vespel SP-1 SP-1 is typically used for jet engine seals, high-temperature bushings, semiconductor process components and aerospace thermal insulators. In short: highest-temperature unfilled polyimide; machined from shape stock; lowest thermal conductivity Vespel.
What is the tensile strength of Vespel SP-1 SP-1?
Vespel SP-1 SP-1 has a typical tensile strength of 86 MPa (12.5 ksi) — stronger than 86% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is Vespel SP-1 SP-1 easy to machine?
Reasonably — machinability is rated good (55/100, worse than 64% of polymer grades). Cut dry at high speed with light feeds using sharp uncoated carbide; the material is dimensionally stable but swells with moisture pickup, and dust extraction is required. It grinds and bores to very high accuracy.
Can Vespel SP-1 SP-1 be welded?
Not readily — weldability is rated not recommended (5/100). Non-melting material; it cannot be welded. Join with high-temperature epoxy or polyimide adhesives, or by mechanical fastening.
What surface finishes work on Vespel SP-1 SP-1?
Normally used as-machined or ground; polishing produces low-roughness sealing faces. Surfaces can be plasma-activated before bonding, but the material cannot be plated.
Can Vespel SP-1 SP-1 be formed, bent or molded?
Cannot be injection moulded or thermoformed. Blanks and shapes are direct-formed from powder by high-temperature, high-pressure sintering and then machined to the finished part.
What is the maximum service temperature of Vespel SP-1 SP-1?
Vespel SP-1 SP-1 is rated for continuous use to about 260°C (500 °F), and briefly to 482°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Vespel SP Polyimide Parts and Shapes — Design Handbook & Typical Properties — DuPont (2020)
- MatWeb polyimide (Vespel SP-1/SP-21) property entries — MatWeb LLC (2024)
- Engineering Plastics — Engineered Materials Handbook Vol. 2 — ASM International (1988)
- ASTM D1708 / D790 / D256 / D149 test methods — ASTM International (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.