When sealing in elevated temperature applications, it is often critical that you select a material that will handle not only the heat, but also the pressure whilst remaining compatible with the medium that you are sealing.
Due to the large number of high temperature gasket materials offered by AG, we decided to put together this page to provide you with a little bit of information about the most popular options. These include high-temperatures compressed fibre materials, graphite based materials, finished metallic gaskets and a few other specialty materials such as Milam PSS, Fireshield Millboard and Lytherm.
Follow the links under each grade for more information.
High Temperature Compressed Fibre Gasket Materials
C4430 Gasket Material
Although very much a general purpose gasket material, C4430 is able to comfortably handle temperatures up to 250ºC and even higher depending on the pressure and media being sealed. This jointing is a great choice when looking for a good all-round gasket material. It also carries many certifications making it suitable for use with oxygen, gas and potable drinking water.
Alapin Gasket Material
Alapin Gasket Material is another general purpose compressed fibre jointing. It can handle continuous temperatures of up to 300ºC and even higher (up to 375ºC) intermittently. Although it lacks some of the certifications that C4430 carries, it is still able to be used with a wide range of media and is a good economical choice.
Alapin-Wire Gasket Material
Alapin-Wire Gasket Material combines the exceptional performance and versatility of AG’s standard Alapin jointing with the addition of a galvanized steel mesh reinforcement which allows the jointing to perform under higher pressures. Like Alapin, it can also handle temperatures of up to 350ºC (250ºC in steam).
Blueguard 3000 Gasket Material
Another popular high temperature compressed fibre in AG’s range. This material offers excellent sealability, improved torque retention and can handle continuous temperatures up to 205ºC. Like all our compressed fibre materials it is available in sheet or cut gasket form.
C4500 Gasket Material
If you are looking for a compressed fibre that will perform under high temperature and high pressure then C4500 is your answer. This premium grade of jointing was designed for use in the chemical industry and can comfortably seal high temperature alkaline media as well as superheated steam. Like C4430, this grade also carries approvals for use with oxygen, gas & drinking water.
High Temperature Graphite Gasket Materials
Topgraph 2000 combines compressed synthetic fibres with graphite to create a high quality gasket sheet that is more flexible and far more stable than other graphite based materials. It is easily able to handle temperatures of up to 350ºC and can even resist temperatures of up to 500ºC depending on media and pressure.
Sigraflex Universal is AG’s premium quality grade of tanged graphite laminate. Manufactured using only the highest purity graphite from SGL carbon, reinforced by a tanged stainless steel sheet, this grade has become a common choice for sealing in a range of high temperature applications where temperatures can reach up to 550ºC.
This high performance grade of graphite laminate utilizes a unique construction of high purity graphite that is reinforced with multiple layers of stainless steel foil. This gives the material outstanding pressure resistance whilst maintaining the high temperature sealing capability that graphite is known for.
Milam PSS – High Temperature Gasket Material for up to 900°C
When it comes to high temperature sealing, Milam PSS provides unrivaled performance. This gasket material is constructed from high-purity mica reinforced with perforated 316 stainless steel. This combination of materials forms a sheet that is non-flammable, non-toxic and allows for effecting sealing in ultra-high temperature environments up to an enormous 900ºC.
Milam PSS is most commonly used in hot dry gas environments such as gaskets for performance exhaust manifolds , turbochargers or turbines and for seals around burner ducting. It is available in two thicknesses (1.3mm & 3.0mm) and AG can supply it in sheet form or as cut gaskets.
Metallic Gaskets for High Temperature Sealing
Depending on the type of high temperature sealing that you are performing, metallic gaskets may be the best option. AG has a large range of Spiral Wound Gaskets in styles W, WR & WRI and Ring-Type Joint (RTJ) Gaskets in both oval and octagonal. We can also quickly fabricate many other types including Kammprofile Gaskets, Metal-Jacketed, Corrugated Metal and Fully Moulded Metallic Gaskets.
Each of these styles have their own unique sealing properties and temperature limits, use the hyperlinks to find out more about each style.
Millboard High Temperature Insulation Board for up to 1,000°C
Fireshield Millboard is a porous insulation board manufactured from mineral fibres and an inorganic binder. Millboard is able to handle temperatures of up to 1000ºC and is often used as a standalone insulation panel, such as for behind stove and oven splash backs. It is also often used for thermal gaskets in applications such as furnace linings, boiler, flue and gas burner seals which is why we have included it on this page.
Millboard does not contain any harmful ceramic fibres and is available in a large range of thicknesses from 1.5mm to 25mm thick. AG is able to supply it in sheets measuring 1000mm x 1000mm or we are able to fabricate it to whichever shape you require.
High Temperature Rope Gaskets
Fibreglass rope is available from AG in two styles, twisted and braided. Twisted Fibreglass rope provides a soft, flexible, economic option whereas braided fibreglass rope is stronger and available in low, medium or high density. Both grades handle temperatures of up to 500ºC and are often used as gaskets, packing or seals in many high-temperature applications.
AG’s ceramic rope offers superior tensile strength and better resistance to temperature than fibreglass rope. Manufactured from glass reinforced ceramic fibres in a twisted construction, Ceramic Rope provides good tensile strength even after continous exposure to temperatures up to 800ºC.
Manufactured from premium quality silica fibres, Refrasil rope offers the most superior temperature resistance of the range, providing long lasting performance in even the most demanding applications. Capable of handling temperatures of up to 982ºC, Refrasil Rope also exhibits outstanding resistance to chemical attack and is much gentler to handle than the fibreglass and ceramic varieties.
Tadpole Tape consists of a bulb and a tail which can each be made from a selection of materials. This versatility makes Tadpole Tape very hard to classify for temperature as it could be as low as 110°C (if made with a Nitrile Rubber Cord bulb) or over 1200°C (when made with a Ceramic Rope bulb).
Because of its unique construction, Tadpole Tape is ideal for sealing and insulating around doors and access ports on high temperature equipment such as the door of a domestic combustion heater or an industrial baking oven, furnace or boiler.
For more information on available options and instructions on how to measure this tape please see our recent post detailing Thermal Tadpole Tape in depth.
High Temperature Gasket Tape
Fibreglass tape from AG is highly flexible with good tensile strength. This insulation tape is available in a variety of styles that can withstand continuous exposure to temperatures as high as 500°C. Available in Industrial grade or a higher density premium grade, it is typically used for lagging applications such as wrapping exhausts, pipes, cables and pipes.
800°C / 1200°C
AG offers Ceramic Insulation Tape in two styles, fibreglass reinforced and nickel-chrome reinforced. Both grades offer excellent chemical resistance however fibreglass reinforced ceramic tape is often used in high temperature electrical applications whereas nickel-chrome reinforced is able to handle higher temperatures but does not perform well as an electrical insulator.
Refrasil Silica Tape
Just like its rope counterpart, Refrasil Tape is manufactured from refractory silica fibres, allowing this tape to perform in higher temperature applications than other tapes in the range. It resists attack from a large variety of media and is more comfortably handled than other grades.
Lytherm Ceramic Paper
Lytherm Ceramic Paper is a high quality grade of heat resistant insulation. This versatile insulation is lightweight, flexible and exhibits very good ageing resistance. It has excellent thermal properties, good chemical resistance and dielectric performance.
Lytherm is able to withstand continuous exposure to temperatures as high as 1260°C (with some other, specialised grades able to go even higher).
Because of this combination of features and benefits, this material is often chosen for making extremely high temperature gaskets and seals as well as other forms of thermal insulation. it is available from AG by the lineal metre or custom fabricated to your specific requirements.
Would You Like More Information?
With over 50 years experience and a huge range of materials in stock, Associated Gaskets is uniquely positioned to help with your high temperature sealing requirements. The materials listed here are just a small portion of what we can offer. If you would like to learn more, or get a little assistance in choosing the best option for your sealing job, please do contact us as we’ll be happy to assist.