Tri-Clamp PTFE Gasket
Tri-Clamp PTFE Gasket
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Solid PTFE tri clamp gasket, FDA compliant, in 1, 1.5, 2, 4 and 6 inch, from $2.95. Every size is priced on this page.
PTFE is the only material in this range that rates excellent against isopropyl, and it is the cheapest way to get full chemical resistance. It also runs to -350 F (-212 C), far colder than any elastomer, which matters more than most people expect.
Sizes and price
| Size | Price |
|---|---|
| 1 in | $2.95 |
| 1.5 in | $2.95 |
| 2 in | $3.25 |
| 4 in | $6.95 |
| 6 in | $19.95 |
The numbers
- Temperature: -350 F to 500 F (-212 C to 260 C)
- Clamp torque: 50 in-lb, the rigid figure. An elastomeric gasket takes 30. Torque a rigid gasket to elastomeric spec and it leaks
- Compliance: FDA compliant
- Excellent on: butane, propane, ethanol, heptane, pentane, hexane and isopropyl
- Behaviour: rigid. It does not spring back, it is subject to creep and cold flow, and it wants a high pressure clamp
If the joint gets broken and remade every run, the PTFE envelope gasket is the better choice. The Viton core inside gives it the recovery that solid PTFE does not have.
Solvent compatibility, by material
| Material | Butane | Propane | Ethanol | Heptane | Pentane | Hexane | Isopropyl |
|---|---|---|---|---|---|---|---|
| PTFE | A | A | A | A | A | A | A |
| Viton (FKM) | A | A | A | A | A | A | D |
| Buna-N | A | A | C | A | E | A | D |
| Silicone | D | D | B | D | D | D | D |
A excellent, B good with minor effect, C fair and not for continuous use, D severe and not recommended, E no data. From the N.B. Oler Sintered Filter Technical Specifications, Rev. 2026.1.
Which material for which job
| Material | Temperature | Torque | Pick it when |
|---|---|---|---|
| Solid PTFE | -350 F to 500 F (-212 C to 260 C) | 50 in-lb | Isopropyl, or cold service. Cheapest route to full chemical resistance |
| PTFE envelope, Viton core | -100 F to 400 F (-73 C to 204 C) | 50 in-lb | PTFE chemistry with spring-back, for joints broken every run |
| Viton (FKM) | -40 F to 400 F (-40 C to 204 C) | 30 in-lb | The hydrocarbon default. Not for isopropyl |
| Buna-N | -30 F to 250 F (-34 C to 121 C) | 30 in-lb | Water, food, general sanitary. Cheapest |
| Silicone | -85 F to 450 F (-65 C to 232 C) | 30 in-lb | Steam and food. Severe on every hydrocarbon |
The cold end is where the gasket governs
An N.B. Oler system operates down to -85 F (-65 C). No fluoroelastomer goes that cold. On the cold end of a run the gasket is the limiting component, not the vessel, which is why PTFE is on this list at all. Check the gasket against your lowest process temperature, not against the vessel rating.
Replacement and quantities
- Replace every 3 to 6 months regardless of how it looks
- Replace immediately on any cracking, tearing, splitting or permanent deformation
- A gasket that has taken a compression set passes a cold leak check and then weeps once the line comes up to pressure. That is why interval beats inspection on a gasket
- A 20 LB system takes 22 six inch gaskets. A 40 LB takes 44
- Full comparison: Choosing the right gasket material for tri-clamp connections
Stocked in Bend, Oregon.