Chemical Resistance
Fluoropolymers such as PTFE, PVDF, and PFA resist nearly every industrial acid, caustic, and solvent, while PPS and PEEK cover aggressive service that also demands mechanical strength.
Products
Machined Polymer Seals & Gaskets
Off the shelf sealing components rarely match the pressure, temperature, chemical, and dimensional requirements of specialized equipment. We machine seals and gaskets from the full range of engineered thermoplastics and filled compounds so critical systems stay tight and stay running.
Why Engineered Polymers
Material properties that drive sealing performance
A gasket forms a static seal between two stationary surfaces. A seal, such as a lip seal or O-ring, works in dynamic service where there is motion. Machined thermoplastics cover both, and the right resin depends on what the part actually sees.
Temperature Range
Grades that run from cryogenic conditions near -328°F through continuous service above 480°F, so the compound can be matched to the actual duty cycle rather than the other way around.
Low Friction & Wear
PTFE, UHMW, acetal, and internally lubricated nylons are self lubricating, which cuts wear, prevents stick slip, and lets dynamic seals run dry.
Purity & Compliance
FDA, USDA, 3A, and NSF compliant grades are available across several resin families for food, beverage, pharmaceutical, and medical adjacent work.
Material Families
Thermoplastics we machine for sealing service
Every family trades something for something else. We pick the one that fits the product being sealed, the pressure and temperature range, and the desired service life.
| Material Family | Key Characteristics | Applications | Limitations |
|---|---|---|---|
| PTFE (Virgin & Filled) | Broadest chemical resistance and lowest friction. Glass, carbon, bronze, graphite, and moly fillers raise compressive strength and cut cold flow. | Flange gaskets, valve seats, chevron sets, back-up rings, cryogenic seals. | Unfilled grades creep under sustained load and have lower wear resistance. |
| PEEK & Filled PEEK | High strength and stiffness to roughly 480°F with excellent creep and steam resistance. Glass, carbon, and PTFE filled grades available. | High pressure seal rings, valve seats, back-up rings, downhole components. | Higher material cost. Attacked by concentrated sulfuric acid. |
| UHMW-PE | Outstanding abrasion resistance and impact strength with a low friction surface and FDA compliant grades. | Wear rings, chute and guide seals, food handling gaskets and pads. | Limited to about 180°F and not suited to tight tolerance high load service. |
| Acetal (Delrin®) & Nylon | Stiff, dimensionally stable, and easy to machine with good fatigue strength. Internally lubricated and glass filled versions available. | Seal carriers, wear bands, bushings, back-up rings, general sealing hardware. | Nylon absorbs moisture and moves dimensionally. Acetal is attacked by strong acids. |
| PVDF, PFA & Fluoropolymer Family | Chemical resistance close to PTFE with more mechanical strength and better creep behavior. High purity grades available. | Chemical pump and valve seals, semiconductor and ultra pure water systems. | Narrower temperature range than PTFE and not for strong bases in some grades. |
| PPS, PEI & Polyimide | High temperature engineering resins with excellent dimensional stability, creep resistance, and load capacity. | Hot gas seals, compressor rings, thrust washers, insulating seal components. | More brittle than the softer families. Requires careful machining strategy. |
Fillers & Compounds
Filled grades tuned to the failure mode
Fillers raise wear resistance and compressive strength and cut down cold flow, the tendency of a material to creep under sustained load. The filler is chosen for how the part is failing today.
Glass Fiber
Increases stiffness, compressive strength, and dimensional stability. Common at 15% and 25% for flange gaskets and valve seats. Can abrade soft mating surfaces.
Carbon & Graphite
Improves creep resistance and thermal conductivity, and adds electrical conductivity for anti-static duty. Well suited to piston and rider rings in water or steam.
Bronze
Highest compressive strength and wear resistance of the common fillers for hydraulic and pneumatic seals, bearings, and wear bands. Avoid in corrosive service.
PTFE, Moly & Internal Lubricants
Added to PEEK, acetal, and nylon to lower the friction coefficient and extend life on dynamic parts running without external lubrication.
Mineral & Ceramic
Raises stiffness and heat deflection while keeping mating surfaces gentler than glass. Useful where dimensional drift under heat is the limiting factor.
Stainless & Metal Detectable
Metal detectable and specialty pigmented compounds for food and pharmaceutical lines where fragment detection is part of the process control plan.
Manufacturing Methods
More than one way to build the part
Stock form and process are part of the engineering. We match the method to the size, the geometry, the volume, and the tolerance you need to hold.
CNC Turning & Milling
Multi-axis turning and milling from rod, plate, and tube stock. The default route for prototypes, replacement parts, and production seals held to ±0.002".
Compression Molded & Sintered Billet
Large diameter PTFE and filled billets molded and sintered, then machined. This is how oversized flange gaskets and heavy wall rings get made without weld lines.
Isostatic & Ram Extruded Stock
Extruded and isostatically molded tube and rod give a tighter, more uniform structure for thin wall rings and long parts that need to stay concentric.
Skiving & Die Cutting
Skived film and sheet cut into gaskets, envelope gaskets, and shim stock where thickness control matters more than turned geometry.
Injection & Transfer Molding
For higher volume thermoplastic parts where tooling investment pays off in piece price and cycle time, with secondary machining where tolerance demands it.
Secondary Operations
Annealing and stress relief, cryogenic machining for tight tolerance work, surface finishing, and assembly of multi-piece seal stacks.
Part Types
Seal and gasket profiles we machine
Our turning and milling capability covers a wide range of sealing geometry in filled and unfilled stock.
Flange Gaskets
Full face gaskets that cover the entire flange and ring type (IBC) gaskets that sit inside the bolt circle. Full face spreads sealing stress evenly for low bolt torque or glass lined equipment, while ring type concentrates pressure at the inner diameter for steam, chemical, and pressure vessel service.
Machined O-Rings
For static sealing where elastomer O-rings fail from chemical attack or temperature. Machined polymer rings hold cross section and sealing geometry in reactor flanges, valve bonnets, and analytical equipment.
V-Rings (Chevron Seals)
Multi-lip stacked sets for high pressure hydraulic cylinders and valves. The V profile stages pressure across several lips, holding a seal well above 3,000 PSI with low friction.
Lip Seals
Dynamic seals that contain pressure and exclude contaminants on rotating shafts. Controlled interference and lip angle keep sealing contact without excess friction or shaft damage.
Piston Rings & Rider Rings
Reciprocating compressor and actuator components. Piston rings seal while rider rings carry the radial load and keep the piston off the cylinder bore, extending equipment life.
Back-Up Rings
Paired with O-rings in high pressure systems to keep the elastomer from extruding into the clearance gap, adding mechanical support without giving up chemical or temperature capability.
Valve Seats, Bushings & Thrust Washers
Machined seats for bubble tight shutoff, plus wear bushings and low friction thrust washers in filled and unfilled grades.
Custom Profiles
If the profile is not listed, send the print, the CAD model, or the worn part. We machine one off prototypes through production quantities.
Applications
Where these seals go to work
Tell us the product being sealed, the pressure and temperature range, and the desired service life. We will recommend the material and the profile.
Chemical Processing
Fluoropolymer and high performance resin sealing for reactors, pumps, valves, and piping flanges exposed to strong acids, caustics, and solvents.
Oil & Gas
Filled PTFE and PEEK handle high pressure and high temperature service, abrasive product, and sour gas in BOPs, valve seals, and flange gaskets.
Food, Beverage & Dairy
FDA compliant and 3A grade polymers for pumps, fillers, and vessels. Non-stick surfaces resist buildup and handle CIP and SIP cycles.
Pharmaceutical & Medical
High purity grades that will not react with active ingredients and withstand autoclave sterilization in bioreactors and sterile fluid handling.
Aerospace & Defense
Cryogenic to high heat service with resistance to hydraulic fluids, jet fuel, and de-icing agents, plus low friction for flight control and actuator hardware.
Semiconductor
High purity PTFE, PFA, and PVDF for ultra pure water and wet etch chemistry that will not leach contaminants or shed particles into the process stream.
The Polytech Advantage
Precision from print to production
We do more than cut parts. We work with your engineering team on material selection and design for manufacturability so the seal performs and the price makes sense.
- CNC turning and milling with calibrated inspection on every job
- Single prototypes, pre-production batches, and full production runs
- Reverse engineering from a used or damaged part
- CAD/CAM drawing and programming from your samples or files
- Lot control, certificates of compliance, and inspection records
Send your print or your sample
Share a drawing, a CAD model, or the worn seal itself. We measure it, program it, and quote both prototype and production quantities out of Rockdale, Texas.
Tolerances held to ±0.002"