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Custom Flange Gaskets: Materials, Dimensions and Ordering Guide
Quick Answer: A custom flange gasket is cut or fabricated for a non-standard flange profile, a special material requirement, or a specific pressure and temperature condition. CORASEALS supplies custom flange gaskets in rubber sheet, PTFE, graphite, non-asbestos, spiral wound, kammprofile, RTJ and sanitary profiles. Send the flange type, gasket standard, ID × OD × thickness, pressure class, temperature, medium and required quantity, and we will prepare a quotation.
Custom flange gaskets solve sealing problems that standard catalog parts cannot cover. A flange may have an unusual outside diameter, a resurfaced face, an enlarged bore, a heat exchanger partition, or a chemical condition that requires a specific material. In these cases, the correct gasket is specified by dimensions, material and flange face type, not by a part number alone.
What is a custom flange gasket?
A custom flange gasket is made from customer dimensions, a drawing, a sample, or a measured flange face. The gasket may be cut from a sheet, machined from PTFE or graphite, formed as a spiral wound component, or produced as a metal RTJ ring. The purpose of the custom gasket is to match the actual flange geometry and service conditions.
Common custom gasket requests include large diameter flanges, non-standard bolt circles, heat exchanger pass bars, manway covers, sanitary connections and flanges that have been resurfaced or repaired. A dimension check is required before production when only a standard flange designation is provided.
Custom flange gasket materials
Material selection must match the medium, temperature, pressure and flange load. The table below lists common material groups and their typical flange service conditions.
| Material group | Common flange service | Selection notes |
|---|---|---|
| NBR rubber sheet | Oil, fuel, water and general industrial | Good oil resistance. Confirm temperature and chemical limits for the specific sheet grade. |
| EPDM rubber sheet | Water, steam, weather and diluted acids | Not suitable for mineral oil, most fuels and many solvents. |
| FKM rubber sheet | Oils, fuels, acids and high temperature service | Check the specific FKM grade against the chemical exposure. |
| PTFE and filled PTFE | Aggressive chemicals, food, pharmaceutical and high purity | Use filled PTFE when creep resistance and dimensional stability are required. |
| Graphite and flexible graphite | Steam, high temperature and heat transfer | Check flange load, oxygen exposure and grade limits for the operating condition. |
| Non-asbestos fiber sheet | Oil, water, steam and mild chemicals | Confirm pressure class, temperature and bolt load for the selected grade. |
| Spiral wound and kammprofile | Piping flanges, heat exchangers and thermal cycling | Specify metal winding, filler, inner ring and outer ring when required. |
| RTJ metal | High pressure and high temperature ASME and API flanges | Specify ring number, material and hardness. |
Actual temperature and pressure limits depend on the specific material grade, sheet construction and flange design. Do not select a gasket material from a general list without checking the chemical compatibility chart for the operating fluid and concentration.
Dimensions, flange face types and standards
For a custom flange gasket quote, provide these dimensions and specifications:
- Gasket ID and OD, or a drawing with the sealing shape
- Gasket thickness
- Flange face type: flat face, raised face, RTJ, tongue and groove, male