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Read morePTFE Nuts, Bolts & Fasteners — Where They Work and Where They Don’t
07 October, 2026 | Admin
Metal fasteners corrode quickly in chemical plants, plating shops, laboratories and seawater-exposed equipment. PTFE nuts and bolts offer a corrosion-free, electrically insulating alternative for light-duty fastening in these environments. They are not a replacement for structural steel fasteners, and understanding their limits is the key to using them successfully.
Why Use PTFE Fasteners?
- Corrosion-proof: PTFE is unaffected by almost all acids, alkalis, salts and solvents, so fasteners do not rust, pit or seize.
- Electrical insulation: PTFE nuts, bolts and washers isolate components electrically and help prevent galvanic corrosion between dissimilar metals.
- Non-contaminating: no metal ions are released into process fluids, which matters in high-purity and laboratory equipment.
- Non-stick and low friction: they will not gall or cold-weld.
- Temperature tolerance: PTFE remains usable up to around 260°C, although strength falls as temperature rises.
Typical Applications
- Securing covers, guards and panels on chemical tanks and scrubbers
- Plating, pickling and anodising lines
- Laboratory and analytical equipment
- Electrical assemblies and insulating mounts
- Semiconductor and high-purity fluid systems
- Insulating kits at flanges where galvanic isolation is needed
Know the Limits
PTFE is soft compared with metals and engineering plastics. Its tensile strength is a small fraction of steel’s, and it creeps under sustained load. In practice, this means:
- PTFE fasteners should carry only light loads, not structural or pressure-retaining loads.
- They must be tightened by hand or to low torque. Overtightening strips threads or deforms the head.
- Clamping force relaxes over time, so joints may need periodic re-tightening.
- Thermal expansion is much higher than metal, so allow for temperature changes.
Alternatives When You Need More Strength
If a fastener must carry more load while resisting chemicals, consider:
- PVDF: stronger and stiffer than PTFE, with excellent resistance to acids and halogens. See PVDF Sheets & Rods.
- PEEK: high strength and stiffness at elevated temperature with broad chemical resistance. See PEEK Sheets & Rods and our PEEK vs PTFE comparison.
- Glass-filled PTFE: somewhat better creep resistance than virgin PTFE, though still a light-duty material.
- Nylon or PP: economical for mild chemical environments at lower temperatures.
Specifying PTFE Fasteners
When enquiring, provide thread size and pitch (metric or imperial), length, head style, quantity, and the chemical and temperature environment. Non-standard fasteners can be machined from PTFE rod to drawing. Matching PTFE washers spread the load and protect soft surfaces. Every order from Diode is supplied with a Material Test Certificate.
Installation Good Practice
- Use a larger diameter or more fasteners than you would with steel, to spread the load.
- Avoid power tools; finish tightening by hand.
- Inspect and re-tighten after initial service and after large temperature cycles.
- Check that the joint will not rely on PTFE fasteners for pressure containment.
Related products: PTFE Products and Virgin PTFE Rods & Sheets.
PTFE Washers, Spacers and Insulating Kits
Fasteners are often only part of the solution. PTFE washers sit under metal or plastic nuts to spread load, seal against leakage and isolate the fastener electrically. PTFE spacers and sleeves keep bolts out of contact with the parts they pass through. Together, they form insulating kits used where pipework or equipment of different metals meets, or where stray currents must be blocked. Washers and sleeves can be cut or machined from PTFE sheet, rod and tube to the sizes you need.
Frequently Asked Questions
Are PTFE bolts strong enough for flange joints?
No. PTFE bolts are for light-duty fastening only and must not be used for pressure-retaining flange bolting.
Why use PTFE nuts and bolts instead of stainless steel?
Where chemicals would corrode stainless steel, or where electrical insulation or metal-free contact is needed.
What is a stronger plastic alternative to PTFE fasteners?
PVDF and PEEK are stronger and stiffer while still offering very good chemical resistance.
Can you machine special PTFE fasteners to drawing?
Yes. We can machine non-standard PTFE screws, nuts and spacers from rod to your drawing.
Request a Quotation
Send your fastener sizes, quantities and service conditions to our Al Khobar team for a quotation on PTFE nuts, bolts, washers and machined fasteners.
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