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Read morePTFE Gaskets — Ready-Cut vs Custom-Fabricated
07 October, 2026 | Admin
PTFE gaskets are used wherever a flange must seal aggressive chemicals, high-purity fluids or food products without contaminating them. Buyers in Saudi Arabia usually face one practical decision before ordering: buy ready-cut PTFE gaskets in standard flange sizes, or have gaskets custom-fabricated from sheet to suit a specific joint. Both routes have a place, and choosing correctly saves time on shutdowns.
What Are Ready-Cut PTFE Gaskets?
Ready-cut gaskets are pre-cut to standard dimensions that match common flange standards, such as ASME B16.5 flanges (with gasket dimensions per ASME B16.21) or EN 1092-1 PN flanges (with gasket dimensions per EN 1514-1). They are usually ring type (inside the bolt circle, IBC) or full face with bolt holes.
- Fast to fit: available by nominal size and pressure class, so maintenance teams can order by line size.
- Consistent: dimensions match the flange standard, which reduces fitting errors.
- Easy to stock: plants can hold common sizes for planned and emergency maintenance.
When Custom-Fabricated Gaskets Make Sense
Custom-fabricated gaskets are cut from PTFE sheet to a drawing, template or sample. They are the right choice when:
- The flange is non-standard, such as heat exchanger covers, manways, tank lids, pump casings and equipment flanges.
- The gasket needs pass partitions, unusual bolt patterns or non-circular shapes.
- A specific grade or thickness is required that is not stocked ready-cut.
- Only a few unusual pieces are needed and making tooling for a standard part does not make sense.
Choosing the PTFE Gasket Material
Virgin PTFE
Best chemical resistance and purity, but it creeps (cold flows) under bolt load, so it is best on flanges with good surface finish and moderate stress.
Filled PTFE
Glass, silica or barium sulphate fillers reduce creep and improve bolt-load retention. Check the filler against the chemical, since glass and silica are attacked by hydrofluoric acid and strong hot alkalis.
Expanded PTFE (ePTFE)
Soft and highly compressible, so it conforms to uneven, damaged or fragile flanges such as glass-lined or plastic flanges.
PTFE Envelope Gaskets
A PTFE jacket over a compressible insert. Only PTFE contacts the fluid, while the insert provides resilience. These are common on glass-lined and FRP equipment.
For a wider comparison, read PTFE vs other sealing materials.
How Custom Gaskets Are Made
Custom PTFE gaskets are typically cut from sheet by CNC knife cutting, water-jet cutting or die cutting, depending on quantity and shape. Small batches and complex shapes usually suit CNC cutting, while large repeat quantities justify a die. Provide a dimensioned drawing, a DXF file or the old gasket as a sample.
Information to Send With an Enquiry
- Flange standard, nominal size and pressure class, or a drawing for non-standard joints
- Gasket type: ring (IBC) or full face
- Thickness, commonly 1.5 mm or 3 mm for flanges
- Process fluid, temperature and pressure
- Quantity, and whether stock should be held for repeat orders
Installation Tips
Use the flange manufacturer’s or gasket supplier’s bolt torque guidance and tighten in a cross pattern in several passes. Because PTFE relaxes after initial loading, re-torquing after a period, where the procedure allows, helps maintain the seal. Never reuse a compressed PTFE gasket. Every order from Diode is supplied with a Material Test Certificate.
Related products: Ready-Cut Gaskets, Gaskets & Seal Materials and PTFE envelope gaskets and seals.
Frequently Asked Questions
Are ready-cut PTFE gaskets available for ASME and EN flanges?
Yes. Ready-cut gaskets are made to standard dimensions for common flange standards; tell us the standard, size and pressure class.
When should I choose expanded PTFE instead of solid PTFE sheet?
Choose expanded PTFE for uneven, damaged or fragile flanges where a softer, more conformable gasket is needed.
Can you cut PTFE gaskets from my drawing?
Yes. Send a dimensioned drawing, DXF file or a sample and we will quote custom-cut gaskets in the grade you need.
Why does a PTFE gasket lose bolt load?
Virgin PTFE creeps under sustained load. Filled grades or envelope designs reduce this, and following the correct torque procedure helps.
Request a Quotation
Send your flange details or drawings, process conditions and quantities to our Al Khobar team for a quotation on ready-cut or custom PTFE gaskets.
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