GORE Joint Sealant, the first form-in-place gasket material, was invented by Gore more than 50 years ago. Since then, this high-temp rope gasket material has proven successful in sealing steel flanges with large diameters, rectangular or irregular shapes, and rough or pitted surfaces.

When compressed, this soft, conformable cord forms a thin yet strong seal. This high-temp rope gasket material is also a chemical-resistant joint sealant that will withstand challenging process conditions and aggressive process media. It can also seal applications where available bolt loads are low, or in applications that demand a gas-tight sealant.

GORE Joint Sealant is a versatile general assembly sealant for many Maintenance, Repair and Operations (MRO) teams because it seals reliably — and because this form-in-place seal is easy and cost-effective to install. For most applications, just peel off the adhesive backing, apply to the surface, and overlap the ends. (For more complex applications, see our installation instructions.)

Of all the joint sealant types, this durable industrial sealant is surely one of the easiest and most versatile solutions for a wide variety of gasketing applications.



Processes using highly-aggressive media:

  • Chemical processing
  • Pulp and paper
  • Mining and minerals
  • Semiconductor manufacturing
  • Power generation

Processes requiring an expanded PTFE joint sealant material:

  • Those that demand a high-temperature joint sealant
  • Those that employ highly-corrosive media
  • Those that need a gas-tight sealant or vacuum gasket cord

Large and/or non-standard steel equipment flanges:

  • Tank manways
  • Handholes and manholes
  • Ductwork
  • Housing covers
A diagram of piping and equipment highlights diverse applications for GORE® Joint Sealant, from ducting and turbines to columns, mixers and tanks

GORE® Joint Sealant creates form-in-place gaskets that reliably seal steel flanges in ducting, columns, turbines, mixers and tanks.

Performance Benefits

A microscopic view of the fibrils that improve the strength and sealing performance of GORE Joint Sealant.

Gore’s expansion technology creates fibrils that enable GORE Joint Sealant to seal irregular flange surfaces more reliably.

Gore’s expanded polytetrafluoroethylene technology

GORE Joint Sealant is made of 100% monoaxially expanded PTFE (ePTFE), using Gore’s expansion technology to create a high degree of fibrillation.

High fibrillation is what improves the joint sealant material’s strength and seal performance, and creates the soft, conformable surface that readily fills minor flange irregularities.

GORE Joint Sealant is versatile enough for use in strong alkali-, acid- and solvent-based chemical process systems, as it is chemically resistant to all media (pH 0-14) except molten/dissolved alkali metals and elemental fluorine.


GORE Joint Sealant is an easy, cost-effective solution for a wide variety of sealing and gasketing applications.

This rope gasket material can instantly be formed in place to fit any shape, regardless of flange size or complexity, or flange condition. It offers installation options for fragile flanges, and for applications where flange rotation must be minimized or prevented.

Supplied on a spool, this expanded ptfe joint sealant is fast and easy to install:

  • Peel away the convenient backing strip.
  • Apply the adhesive-backed sealant to the flange.
  • Overlap the sealant ends to form a durable and reliable gasket.

With GORE Joint Sealant, even sealing vertical flanges is a one-person job.

» See how easy it is to use GORE Joint Sealant: view our Installation Guide


When time is money, Gore can help you save both

With GORE Joint Sealant, creating custom large gaskets on the spot is swift and simple, because your form in place gasket is immediately available. No need to wait for one to be fabricated off-site. No need for extra gaskets-and-seals procurement efforts to receive pallets, or requisition trucks or crane-lifts. No need for special handling or maintenance required, either.

Gasket creation and gasket installation are faster and easier with GORE Joint Sealant. Its tight, durable seal means maintenance is minimal, too. With fewer interruptions and less downtime, productivity is higher all around — and so are the related cost savings.

Technical Specifications

  • 100% expanded PTFE (polytetrafluoroethylene), with monodirectional strength
  • This product is supplied with an adhesive backer only to aid in the product installation
Temperature Range -269 °C to +315 °C (-452 °F to +600 °F)
Chemical Resistance Chemical resistance to all media pH 0-14, except molten alkali metals and elemental fluorine.
Operating Range The maximum applicable pressure and temperature depend mainly on the equipment and installation.
  • Typical use: -60 °C to 150 °C (-76 °F to 300 °F); industrial full vacuum(1) to 10 bar (145 psi)
  • For higher pressures, please contact Gore.
Shelf Life Expanded PTFE is not subject to aging and can be stored indefinitely. To ensure optimal adhesive function, we recommend use within two years of date of purchase when stored under normal(2) conditions.

(1) absolute pressure of 1 mmHg (Torr) = 133 Pa = 1.33 mbar = 0.019 psi
(2) 21°C (70 °F) 50% Relative Humidity

Width(3) 3 mm (1/8") 5 mm (3/16") 7 mm (1/4") 10 mm (3/8")
  14 mm (1/2") 17 mm (5/8") 20 mm (3/4") 25 mm (1")

(3) GORE Joint Sealant is very conformable. Therefore prior to compression its dimensions are easily changed during storage and handling. Minor variation of dimensions in the uncompressed state have no influence on product performance.

Test Data

Test Results

  Thickness Exposure Temp. Initial Gasket Stress Test Step 1 Test Step 2
VDI 2200 (06-2007)
DN 40 / PN 40 Steel
2 mm
150 °C
(302 °F)
30 MPa
(4,350 psi)
Yes, 60 bar
(870 psi)
Yes, 60 bar
(870 psi)

GORE® Joint Sealant in 5 mm width was tested.

Test Method

"The aim of the VDI guideline is to analyze and organize the applicable seal connection conditions based on the technical standard. Furthermore to complete the conditions, including latest research results, and advise the user in selection, interpretation, design, and assembling of flange joints in particular consideration of the gaskets."(1) "The here described blowout safety test of seals in sealing systems with even flanges corresponds with the current state of test engineering [...] a seal itself cannot accomplish blowout safety. It always depends on the entire system of the flange joint.

General Test Procedure

  1. Installation of seal with installation surface pressure in four steps (25 %, 50 %, 75 % and 100 % of bolt force through crosswise tightening). Installation surface pressure and seal thickness are to be indicated in the test record. The lift-off force, caused by the nominal pressure, referring to the middle seal diameter, shall additionally be considered in all testing steps.
  2. Retightening to installation surface pressure after 5 minutes.
  3. Flange heating to temperature with 2 K/min in recirculation furnace or using inside heated cartridges.
  4. Maintenance of thermal storage temperature for minimum 48 hours.
  5. Cooling down of the flange to ambient temperature.
  6. Measurement of the remaining surface pressure.

Test Step 1

The blowout safety test is performed with nitrogen up to the 1.5-fold of the nominal pressure. Tests with higher pressures are allowed, if required. The internal pressure is to be increased stepwise, in steps of 5 bar to the above mentioned pressure. The holding period per pressure stage amounts to a minimum of 2 min.

As "blowout" is defined, if, within 5 s, a pressure decay of Δp ≥ 1 bar· (V0 = test room volume) is exceeded. The achieved internal pressure is to be indicated in the test record. If blowout did not occur until the maximum test pressure, the test is to be continued according to test step 2.

Test Step 2

The internal pressure is discharged and the surface pressure is reduced to 5 N/mm2 with regard to lifting force caused by the internal pressure. Variations of the surface pressure are to be stated in the testing report."(2)

(1) Source: Verein Deutscher Ingenieure e. V.: VDI 2200: Tight flange connections - Selection, calculation, design and assembly of bolted flange connections, June 2007, page 4
(2) Source: ibidem, page 64

Gasket Design Factors

Test Results

Please find below the EN 13555 test results:
GORE® Joint Sealant in 2 mm (0,08")

EN 13555 specifies a test flange that is DN 40 / PN 40 in size; therefore, GORE® Joint Sealant DF05 was tested using a stiffness of 500 kN/mm. Results for all other sizes were extrapolated from DF05 results using the following compression curve.

Test Method

EN 13555 provides the test method for generating the gasket parameters used in EN 1591-1 calculations. The informative Annex G now provides some guidance for generating gasket design parameters for form-in-place products.

Due to the material properties of monoaxially expanded PTFE, the increase in the gasket width of GORE® Joint Sealant depends on the pressure exerted on it. For the configuration and calculation of flange connections it is therefore easier to use line forces instead of gasket stress. The line force, Q*, is the ratio of the force per unit length.

Gasket Constant Definitions Modified for GORE® Joint Sealant

PQR A measure of creep relaxation at a predefined temperature. It is the ratio between the gasket stress after relaxation and the initial gasket stress. The ideal PQR value is 1. The closer the test value is to the ideal value, the lower the loss of gasket stress of the seal.
Q*min(L) The minimum required line force at ambient temperature for a certain leakage class L when the seal is first installed.
Q*Smin(L) The minimum required line force for a certain leakage class L in service.
Q*Smax The maximum line force that may be applied on the gasket, without damage or intrusion into the bore, at the indicated temperatures. It depends on the temperature and the seal thickness.
E*G This describes the recovery (elastic behavior) of a seal at load reduction. It is related to the modulus of elasticity. It depends on the applied line force, the seal thickness and the temperature.


General Test Method Description

PQR Creep Relaxation is measured at different temperatures, initial gasket stress, seal thickness values and flange stiffness values. The seal initially is exposed to the predefined gasket stress, then the temperature is increased and maintained for four hours. The residual gasket stress is then measured.
A load is applied to and removed from the seal in predefined increments, with the leakage being measured constantly. The internal pressure is usually 40 bar (test gas: helium).
The gasket stress is increased cyclically and then reduced to 1/3 of the previous gasket stress. The seal thickness is then measured. The test is repeated at various temperatures.

The E*G value is calculated from the load reductions and thickness changes. For Q*Smax, a sudden drop in seal thickness indicates failure. If a sudden drop occurs, the value of the loading step before failure is taken. In case no failure occurs, the maximum possible gasket stress of the test equipment is taken. The identified value is then used as the initial stress in a PQR test to verify the final Q*Smax under constant loading.
GORE® Joint Sealant - Compression Curves at Room Temperature

Q*min [N/mm]

  L1,0 L0,1 L0,01 L0,001
3 mm (1/8") 37 65 97 129
5 mm (3/16") 50 90 140 190
7 mm (1/4") 68 119 183 244
10 mm (3/8") 104 183 286 381
14 mm (1/2") 146 261 411 554
17 mm (5/8") 179 315 506 678
20 mm (3/4") 190 344 546 734
25 mm (1") 276 513 832 1128

Q*Smin [N/mm]

  Q*A [N/mm] QA [MPa] L1,0 L0,1 L0,01 L0,001
3 mm (1/8") 100 33 37 37 x x
200 67 37 37 37 88
300 100 37 37 37 50
400 133 37 46 55 65
5 mm (3/16") 100 20 50 50 x x
200 40 50 50 50 135
300 60 50 50 50 70
400 80 50 60 75 90
7 mm (1/4") 100 14 68 68 x x
200 29 68 68 68 162
300 43 68 68 68 92
400 57 68 85 101 119
10 mm (3/8") 100 10 104 104 x x
200 20 104 104 104 250
300 30 104 104 104 143
400 40 104 129 156 183
14 mm (1/2") 100 7 146 146 x x
200 14 146 146 146 353
300 21 146 146 146 202
400 29 146 183 221 261
17 mm (5/8") 100 6 179 179 x x
200 12 179 179 179 435
300 18 179 179 179 248
400 24 179 224 272 317
20 mm (3/4") 100 5 190 190 x x
200 10 190 190 190 464
300 15 190 190 190 265
400 20 190 240 291 344
25 mm (1") 100 4 276 276 x x
200 8 276 276 276 683
300 12 276 276 276 390
400 16 276 351 430 513

X: The leakage rate is not achieved at the pre-compression line force Q*A as part of the measuring program.


  PQR @ QSmax QSmax Q*Smax 1 Temperature
5 mm (3/16") 0.97 200 MPa
(29,010 psi)
1000 N/mm Room
0.89 200 MPa
(29,010 psi)
1000 N/mm 80 °C
(212 °F)
0.92 200 MPa
(29,010 psi)
1000 N/mm 150 °C
(302 °F)

1   Corresponds to inital gasket stress (initial width = 5 mm)


  EG Gasket stress Line force 1 Temperature
5 mm (3/16") 290 20 MPa (2,900 psi) 100 N/mm Room
368 30 MPa (4,350 psi) 150 N/mm
438 40 MPa (5,800 psi) 200 N/mm
490 50 MPa (7,250 psi) 250 N/mm
527 60 MPa (8,700 psi) 300 N/mm
500 20 MPa (2,900 psi) 100 N/mm 80 °C
(212 °F)
581 30 MPa (4,350 psi) 150 N/mm
671 40 MPa (5,800 psi) 200 N/mm
817 50 MPa (7,250 psi) 250 N/mm
971 60 MPa (8,700 psi) 300 N/mm
260 20 MPa (2,900 psi) 100 N/mm 150 °C
(302 °F)
374 30 MPa (4,350 psi) 150 N/mm
380 40 MPa (5,800 psi) 200 N/mm
377 50 MPa (7,250 psi) 250 N/mm
369 60 MPa (8,700 psi) 300 N/mm

1   Corresponds to inital gasket stress (initial width = 5 mm)

Test Results

m 1.5
y 2500

Test Method

m & y are gasket constants used for flange design as specified in the ASME Boiler and Pressure Vessel Research Code Division 1 Section VIII Appendix 2. Leak Rates versus Y stresses and m factor for Gaskets is currently being proposed as a new test method in the ASTM F03 Working Group.

Gasket Constant Definitions

m, maintenance factor, is a factor that describes the amount of additional preload required to maintain the compressive load on a gasket after internal pressure is applied to a joint.

y, seating stress, is the minimum compressive stress (psi) required to achieve an initial seal.

Test Results

For GORE® Joint Sealant in 2 mm thickness and with an internal pressure of 10 bar (145 psi), this results in:

k1 10 • bD
k0KD 18 MPa • bD
k0KDϑ  200 MPa • bD temperature ϑ = 150 °C (302 °F)

Test Method

There are no specific test standards for AD 2000 B 7 Gasket Parameters. However, an estimation is provided below. The 2015 edition of "AD 2000-Merkblatt B 7" refers to EN 13555 as a test standard(1) and uses table 9 from VDI 2200(2) for the conversion method. Please note that VDI 2200 states that such a conversion is invalid due to the different measurement methods. "Only the method according to DIN EN 1591-1 and AD 2000 in conjunction with DIN EN 1591-1 and FE analysis can be used for providing stability, leak tightness and TA Luft proof." (3)

Gore supports the use of the AD 2000-Merkblatt B 7 and provides the necessary gasket parameters below.

There are the following relations(1):

k0KD ≙ Qmin · bD
k1 ≙ (QSmin / p) · bD since m ≙ QSmin / p (4)
k0K ≙ Qsmax · bD

Qmin minimum required gasket stress at ambient temperature when the seal is first installed (based on EN13555)
QSmin minimum required gasket stress in service (based on EN13555)
QSmax maximum gasket stress that may be applied on the gasket at an indicated temperature ϑ (based on EN 13555)
bD width of the gasket
p internal pressure of the media
k1 AD 2000 B7 gasket parameter for service condition
k0KD AD 2000 B7 gasket parameter for gasket deformation
k0K AD 2000 B7 gasket parameter for gasket deformation in service at temperature ϑ

If necessary for a specific application, Gore recommends to do individual conversions based on data from EN 13555.

The use of the general values given in table 1 of AD 2000-Merkblatt B 7(5) is not broadly recommended. However they may be applicable depending on the given situation.

Please also note that the quoted standards of DIN 2690 to DIN 2692 were superseded by EN 1514-1 in 1997.

(1) Arbeitsgemeinschaft Druckbehälter: AD 2000-Merkblatt B 7, Berechnung von Druckbehältern, Schrauben, Seite 4,, April 2015
(2) Verein Deutscher Ingenieure e. V.: VDI 2200, Tight flange connections - Selection, calculation, design and assembly of bolted flange connections, page 36, table 9, June 2007
(3) Verein Deutscher Ingenieure e. V.: VDI 2290, Emission Control - Sealing constants for flange connections, page 8, June 2012
(4) Please note that factor m = QSmin / p was defined by DIN V 2505 which was superseded by EN 1591-1 where m is no longer used
(5) Arbeitsgemeinschaft Druckbehälter: AD 2000-Merkblatt B 7, Berechnung von Druckbehältern, Schrauben, Seite 6, Tabelle 1, April 2015


For the TA Luft1 test, the seal is installed in a DN40/PN40 steel flange, usually with a gasket stress of 30 MPa. The flange is then exposed to a defined temperature for minimum 48 hours. After cool down, leakage rate is measured over a period of at least 24 hours. The test pressure is 1 bar helium.

The ultimate final leakage rate after a test duration of 24 hours must remain below 10–4 mbar*l/(s*m) for the seal to qualify according to TA Luft.

Federal Ministry of Germany for the Environment, Nature Conservation, Building and Nuclear Safety: First General Administrative Regulation Pertaining the Federal Emission Control Act (Technical Instructions on Air Quality Control - TA Luft), Joint Ministerial Gazette, July 30, 2012.

The Federal Institute for Materials Research and Testing (BAM) tests the sealing material compatibility for use in flanged connections with liquid and gaseous oxygen. Further information on the test procedure and the result can be found in the following test report. Please note that the test was conducted without adhesive backing.

The DVGW (Deutscher Verein des Gas- und Wasserfaches e.V.) is the German Technical and Scientific Association for Gas and Water. It tests sealing materials according to the DVGW VP 403 norm "Expanded polytetrafluoroethylene (PTFE) sealing profiles for flange connections in the gas supply industry." GORE® Joint Sealant in 5mm (3/16") width fulfills all requirements of this norm and is therefore suitable for natural gas applications.

This test analyzes leachable water-soluble fluoride and chloride ions which can induce flange corrosion. The samples are leached for 24 hours at approximately 95 °C in demineralized water. Contact Gore for further information if this testing is required for your application.

GORE® Gasketing products meet the definition of an article; therefore, a Material Safety Data Sheet (MSDS) or Safety Data Sheet (SDS) is not required. However, for your convenience, a Product Safety Sheet (PSS), which details the intended use and proper handling of our articles, is provided.

The Gore Sealant Technologies Quality Management System is certified in accordance with ISO 9001.




Not for use in food, drug, cosmetic or medical device manufacturing, processing, or packaging operations.