Vespel Specifications — Rod, Tube Sizes & Tolerances

Vespel is manufactured by DuPont (now operating through DuPont and its affiliated IST business) using two consolidated processes: direct forming into near-net shapes and isostatic pressing of rod and tube billets. Unlike commodity plastics where you order sheet or rod by the foot from broad inventory, Vespel availability is more constrained — the production process is slow, yields are limited, and the material commands lead times that reflect that reality. This page covers stock forms, standard diameter ranges, dimensional tolerances, and the cost context every buyer needs before committing to Vespel in a design.

At a Glance

• Rod stock: 1/4" through 6" diameter in SP-1, SP-21, SP-22
• Tube: available in standard sizes; wall thickness and ID combinations vary by grade
• Flat sheet/plate: not a standard stock form — special order with significant lead time
• Dimensional tolerances: tighter than most thermoplastic rod; isostatic pressing produces consistent cross-sections
• Lead times: typically 4–12 weeks for non-stocked sizes; consult distributor for current availability
• Cost: most expensive unfilled plastic per pound — typically $200–$800+ per foot of rod depending on diameter and grade
• Custom direct-formed shapes available from DuPont/IST with minimum quantity requirements

Rod Stock

Standard Diameter Range

Vespel rod is available from 1/4" (0.250") through 6" diameter. Standard increments follow the pattern below, though not all diameters are stocked at all distributors — confirm availability before designing to a specific size.

Lengths available per rod vary by diameter and grade. Common cut lengths range from 6" to 24", with full press lengths typically 12"–18" for larger diameters. Stock is generally sold by the inch or by the piece rather than by the foot as with commodity rod.

Rod Tolerances

Isostatically pressed Vespel rod holds tighter tolerances than extruded thermoplastic rod because the consolidation process produces uniform cross-sections without the residual stress and diameter variation common in extruded material.

Tube Stock

Vespel tube is available in a range of OD/ID combinations for SP-1 and SP-21. SP-22 tube is less commonly stocked. Standard sizes cluster around ODs from 1/2" to 4" with wall thicknesses from 1/8" to 3/4". Non-standard wall configurations require direct-form tooling or significant machining from rod.

Common applications driving tube selection include:

• Journal bearing sleeves pressed into housing bores — OD tolerance to the housing bore, ID bored to shaft diameter
• High-temperature shaft seals — tube slid over shaft, machined to final geometry
• Spacer tubes in precision assemblies — wall thickness tolerance critical for stack-up

Tube is typically more expensive per pound than rod due to lower material yield in the pressing process. If a tube wall is thin relative to OD, machining from rod may be cost-competitive depending on diameter and quantity.

Flat Sheet and Plate

Vespel is not stocked as flat sheet in standard distributor inventory. Plate (slab) forms can be produced by DuPont/IST as special orders, but the minimum quantities, lead times (often 12–20 weeks), and per-pound costs are substantially higher than rod or tube.

If your application requires flat plate:

1. Evaluate whether the part can be redesigned to use rod (face-turned to a disk, then bored/profiled)
2. Consider PEEK sheet or PAI (Torlon) sheet if the temperature requirement does not absolutely demand Vespel
3. Contact DuPont/IST directly for plate programs if the temperature or chemical environment eliminates alternatives

Custom and Near-Net Direct-Formed Shapes

For production quantities of complex shapes — wear pads, valve components, custom bearing geometries — DuPont's direct forming process can produce near-net-shape parts that minimize machining waste on an expensive material. Direct forming requires:

• Tooling: DuPont/IST controls the tooling; customers provide engineering requirements, not tooling hardware
• Minimum quantities: Typically 25–500 pieces depending on part complexity and tooling amortization
• Lead times: 12–24 weeks for new part qualification, shorter for reorders
• Certifications: Material test reports (MTR) and chemical certifications available for aerospace and defense programs

For prototype and low-volume work, machining from rod or tube stock is the practical path. For high-volume parts where material yield is cost-significant, direct forming should be evaluated.

Cost Premium Context

Vespel is the most expensive plastic per pound in the high-performance engineering plastics line card. Representative pricing for context (market-dependent; confirm current pricing):

These figures represent typical distributor pricing for standard stocking grades. SP-21 and SP-22 carry modest premiums over SP-1 in small diameters; the relationship can reverse in larger diameters depending on production schedules.

Cost Justification Framework

Vespel is not a material to specify casually. The cost makes sense when:

1. Temperature eliminates alternatives — PEEK can't survive the environment, Torlon is borderline, and Vespel is the only qualified material
2. Wear life justifies the premium — a Vespel wear pad running 6,000 hours vs. a PEEK pad running 1,500 hours changes total cost of ownership on high-uptime equipment
3. Specification control — OEM drawings that specify Vespel SP-21 by name for an AS9100-certified assembly leave no qualification pathway to substitute
4. Scarcity of alternatives — no other stock shape material provides combined vacuum compatibility, electrical insulation, and 500°F+ continuous operation in SP-1

For a detailed cost-performance comparison against PEEK and Torlon, see the Vespel comparisons page and the Vespel vs PEEK head-to-head.

Certifications and Traceability

Standard distributor Vespel includes:

• Certificate of Conformance (C of C) — attests material is DuPont Vespel of the specified grade
• Material Test Report (MTR) — lot-level physical property data against specification minimums
• Country of Origin — required for ITAR and EAR compliance on defense programs

For AS9100 / NADCAP aerospace programs, first-article inspection (FAI) documentation and raw material traceability through the heat/lot number are standard requirements. Confirm with your distributor that the batch in stock carries the required documentation before cutting purchase orders.

For current stocking levels, lead times, and pricing, contact our materials team or visit the Vespel product page.

More related guides

Cross-cluster suggestions to help shoppers and engineers explore adjacent topics:

Applications

• Bushings Bearings

Industries

• Aerospace
• Defense Military

Compare to other materials

• Torlon Vs. Vespel
• Vespel Vs. Peek

Frequently asked questions — Polyimide Vespel FAQ