The following are some Frequent Asked Questions for flexible graphite based items. If you have any other questions, please feel free to contact us. We will give you an immediate reply.

What are some typical characteristics of this flexible graphite?
Is flexible graphite chemically compatible with my process fluid?
Can flexible graphite gaskets be used in cryogenic service?
Can flexible graphite gaskets be used in oxygen service?
How is Flexible Graphite manufactured?
How big of a flexible graphite gasket can I buy?
What is the maximum temperature and pressure for using flexible graphite gaskets?
What surface finish should my flanges be?
What thicknesses and sizes are available?
What densities are available?
What is Flexible Graphite?

What is Flexible Graphite?
Flexible Graphite is a distinctive material with essential characteristics of graphite but with complementary properties different from conventional manufactured carbons or graphite such as those used in mechanical seals. When flexibility, compactibility, conformability, and resilience are added to graphite's basic properties, you have the characteristics of "flexible graphite." You also have a superior high-performance packing and gasket material.

How is Flexible Graphite manufactured?
The unique properties of flexible graphite products begin with natural graphite flakes found in major deposits in China, Madagascar, Canada, Brazil, and Russia. ?Only high quality raw graphite flake is used in our production.

SinoSeal manufactures Flexible Graphite as a rolled sheet product by taking a high quality particulate graphite flake and processing it through an intercalation process using strong mineral acids. The flake is then heated to volatilize the acids and expand the flake to many times its original size. The expansion process produces a wormlike, dendritic structure that can be readily formed by molding or calendering into sheets. No binders are introduced in the manufacturing process. The result is a sheet product that exhibits excellent tensile strength and, for industrial applications, typically exceeds 98% elemental carbon by weight.

What are some typical characteristics of this material?
Flexible Graphite is flexible, compressible, resilient, chemically inert, fire safe, and stable under load and temperature. It is also anisotropic due to its crystalline structure and has excellent directional, electrical and thermal conduction properties. Flexible Graphite has found applications in chemical gasketing, high temperature automotive gasketing, heat shielding, and noise damping components. It is also effective in electronics applications involving RFI and EMI shielding, as well as heat sink applications.

Is flexible graphite chemically compatible with my process fluid?
SinoSeal flexible graphite is chemically compatible with a very wide range of chemicals, from pH 1 to 14. ?flexible graphite gaskets are chemically compatible with nearly all of the petroleum based products, gasoline, grease, oils, etc., most solvents, and many acids and bases.? The list of compatible chemicals is very long and it is easier to identify the types of chemicals to avoid since it is a much smaller list.? Specific acids to avoid are concentrated mineral acids such as nitric acid and sulfuric acid.? Other chemicals to avoid include strong oxidizing chemicals such as aqua regia, or peroxides.? When using gaskets cut from flexible graphite laminated materials it is important to check the chemical compatibility of the insert material as well as the flexible graphite facing.?

What thicknesses and sizes are available?
Flexible Graphite is available starting with 0.2mm. maximum of 1mm can be found in roll form. Thicker than 1mm, it will be hard to roll it up since the surface may observe cracks when it is bent. They are supplied in sheets form for thickness over 1mm. Our standard production line widths are 1000mm, 1500mm and 2000mm. Material can also be supplied in custom slit widths or cut sheets. We can also laminate sheets, to form virtually any thickness desired.

What densities are available?
Standard density for Flexible Graphite is 70 lbs/ft3 (1.12 g/cc). However, depending on thickness and order size, densities can be manufactured from below 50 lbs/ft3 up to 90 lbs/ft3.

How big of a flexible graphite gasket can I buy?
Flexible graphite sheet and laminate materials are available up to 1500mm and 2000mm in width. ?laminates use a welded one piece insert to insure that the full 60” of width is available for use.? Standard laminate sizes are 24” x 24” (724 mm x 724mm), 39.4” x 39.4” (1m x1 m), 39.4 x 78.8” (1m x 2m), 60” x 60” (1.5 m x 1.5 m) and 78.8” x 78.8” (2 m x 2 m). or even sheets are available in rolls of 39.4” width or 1 meter wide and any length up to 4000’.

What is the maximum temperature and pressure for using flexible graphite gaskets?
Our oxidation and corrosion inhibited flexible graphite grades are all rated for continuous service to 975°F in oxidizing (air) environments in all Class 150 and Class 300 flanges for continuous service.

In shielded , neutral, reducing, or vacuum environments, flexible graphite is rated to 3000°C.

What surface finish should my flanges be?
Flexible graphite is a fairly soft gasketing material and readily conforms to any surface finish it is pressed against.? Flexible graphite gaskets can be used with flange finishes from 5 micro inch to 500 micro inch, but we recommend a 125 to 250 micro inch finish .? Flanges can have either spiral, concentric or no serrations.

Can flexible graphite gaskets be used in oxygen service?
Yes, flexible graphite are all approved for use in gaseous or liquid oxygen up to 735°F (400°C) and pressures up to 2000 psig.

Can flexible graphite gaskets be used in cryogenic service?
flexible graphite gaskets can be used at cryogenic temperatures. flexible graphite maintains its flexibility and compressibility and therefore sealability totally independent of temperature.? It will not stiffen or harden at cryogenic temperatures.

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