Gasket material
PTFE Gasket Material
PTFE gaskets in virgin, filled and expanded sheet for chemistry no elastomer survives: the forms we cut on the waterjet, the ASTM F104 classes, and creep as the design issue.
- Family
- PTFE (virgin, filled and expanded sheet)
- Temperature range
- Set by the grade; the filled and expanded PTFE pages cite one sheet each
- Durometers
- not applicable (non-elastomer)
- Standards
- ASTM D3308, ASTM D3294; ASTM F104 Type 4 Class 1, 2 and 5
- Product
- Sheet gaskets waterjet-cut to your drawing in Orange, California
Every common gasket sheet material is quick for us to source, and we cut it to your print on our waterjet.
PTFE gaskets give near-universal chemical resistance in a non-elastic material: virgin, filled and expanded PTFE sheet resists nearly every medium a rubber gasket cannot, and the design problem moves from chemistry to creep and bolt-load retention. Each PTFE grade sheet (virgin, filled, expanded) states its own temperature range. Conquest cuts PTFE sheet gaskets on the waterjet, the correct process for a material that must never be laser-cut.
What we cut
Conquest cuts sheet gaskets on a pure-water waterjet, the one product made in house. Typical figures for waterjet-cut gaskets, as fabricators and a waterjet maker publish them rather than a Conquest machine spec: a pure-water jet cuts sponge 2 in thick and solid rubber over 1 in with a square edge and no die concavity (Stockwell Elastomerics), leaves a kerf of 0.003 to 0.015 in (Flow International), and holds plus or minus 0.010 in on dimensions under 12 in and plus or minus 0.020 in on larger parts (NEDC, sponge and foam gaskets). There is no die to build, so prototypes, revision changes and short runs go through the same setup as a repeat, and expensive stock nests tightly with no die-skeleton waste. Molded and lathe-cut parts, and non-sheet compounds, are supplied from our manufacturers.
PTFE gasket specifications
| Property | Value | Source |
|---|---|---|
| Temperature range | Set by the grade; the filled and expanded PTFE pages cite one sheet each | The grade sheet |
| Forms cut | Virgin (skived) PTFE; filled PTFE (glass, mineral or barium-filled, GYLON®-type); expanded PTFE (GORE®-type) | Conquest Seal sheet list |
| Sheet thicknesses | 1/32, 1/16, 1/8, 1/4 in (virgin); 1/32 to 1/8 in (filled and expanded) | Conquest Seal sheet list |
| Sheet forms | 12 x 12, 24 x 24, 36 x 36 in (virgin); 30 x 30 and 60 x 60 in (filled and expanded) | Conquest Seal sheet list |
| Specification callouts | ASTM D3308 and D3294 (virgin PTFE sheet); ASTM F104 Type 4 Class 1 (virgin), Class 5 (filled), Class 2 (expanded) | Conquest Seal sheet list |
| Cutting note | Waterjet only; PTFE is never laser-cut (it decomposes to hydrogen fluoride and other toxic gases) | General practice |
| Design issue | Creep under bolt load; filled and expanded grades reduce it | General practice |
Which PTFE, for which duty?
| Form | Strength | Weakness | Typical duty |
|---|---|---|---|
| Virgin (skived) PTFE | Purest; broadest chemical resistance; FDA-compliant grades common | Creeps most under load; loses bolt torque | Low-pressure chemical and food flanges, liners |
| Filled PTFE (GYLON-type) | Much better creep resistance; holds torque | Filler narrows chemical resistance slightly | Chemical-process flanges at pressure |
| Expanded PTFE (GORE-type) | Conforms to rough and warped faces; low bolt load | Compressible; needs stops on some joints | Glass-lined and fragile flanges, large diameters |
| PTFE-envelope over a rubber core | PTFE face with rubber resilience | Limited thickness; core material limits temperature | Raised-face flanges in mixed chemistry |
| PTFE backup rings (MS27595, MS28774) | Anti-extrusion for O-rings at pressure | Not a gasket | Hydraulic glands; see the groove design guide |
| UHMW and other plastics | Abrasion resistance | Lower temperature than PTFE | Wear pads, not gaskets |
Where PTFE is used, and the usual alternatives
It is usually specified where the medium defeats every elastomer (strong acids and bases, solvents, mixed chemistry), where nothing may leach into the product, or where a flange is fragile and needs the low seating stress of expanded PTFE. It is not the sheet where the joint needs elastic recovery or sees vibration and thermal cycling that unload the bolts; a rubber gasket (Viton®, EPDM) or a PTFE-envelope gasket keeps its seal there. The material is PTFE, whatever trade name the print uses.
Sources: ASTM D3308; ASTM F104; MS27595; MS28774; Conquest Seal sheet list (September 2026); typical waterjet figures, not a Conquest machine spec: Stockwell Elastomerics, Waterjet Cutting; Flow International, Waterjet Dictionary; NEDC, Die-Cut and Waterjet Cut Tolerances for Sponge/Foam Gaskets (each read 2026-09-24).
Garlock® and GYLON are trademarks of Garlock Sealing Technologies; GORE is a trademark of W. L. Gore & Associates; Viton is a trademark of The Chemours Company. No affiliation or endorsement is implied.
Reviewed by Grant Midstokke, Conquest Seal Corporation. Last updated September 2026. Material ranges are the published references named beside them; the sheet's own datasheet and your application govern the final choice.
Frequently asked
Why does a PTFE gasket leak after a few heat cycles?
Creep: the material flows under bolt load and the torque relaxes. Filled or expanded PTFE, or re-torquing after the first cycle, is the usual fix.
Is PTFE food safe?
Virgin PTFE grades are widely offered FDA compliant; the grade sheet, not the material name, is the evidence.
Can PTFE be laser-cut to save cost?
No. Laser cutting decomposes chlorinated and fluorinated polymers into toxic gases, so we cut them on the waterjet.
What is an ASTM F104 callout?
The line-callout system for non-metallic gasket materials; Type 4 is PTFE and the class digit names virgin, filled or expanded.
Related guides
Send the PTFE gasket drawing and the quantity
A DXF, DWG or PDF of the gasket, the sheet thickness, the PTFE form or grade and the quantity. Gaskets are cut in our own shop in Orange, California; a Conquest representative replies.
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