Sheet in PTFE GF15 1200x1200 mm natural

PTFE GF15 is a step up from GF10. Fifteen percent glass fiber raises the compressive strength further, pulls the creep down and makes the sheet more dimensionally stable under long term load. The material still keeps most of the chemical properties and the low friction of PTFE, but sits more clearly on the mechanical side of the PTFE scale. That makes the grade suitable for flange gaskets in higher pressure classes, for slide plates with higher surface pressure and for valve seats where a strict cold flow margin is required across the whole service life.

The density is around 2.2 to 2.25 grams per cubic centimeter depending on the exact fill level. The color is pale white to light gray. The long term temperature follows the PTFE base and lies at about 260 degrees; downward the material goes to cryogenic levels without turning brittle or cracking. The flame class is V0. Thermal expansion is lower than for pure PTFE, which is a practical advantage in bolted sealing joints where dimensional changes during heating and cooling can otherwise loosen the joint. The coefficient of friction is still at low levels, marginally above pure PTFE but far below most other engineering plastics.

Chemically, PTFE GF15 resists more or less every industrial fluid: acids, bases, solvents, oils, alcohols, chlorinated hydrocarbons, ozone. The glass fiber is sensitive to strong caustic at high temperature and to hydrofluoric acid, so in those specific cases pure PTFE or an inorganically filled grade is the safer choice. Water absorption is negligible and the material is dimensionally stable over time even in damp or fully submerged environments. The dielectric properties are still very good, which means GF15 sheets are also used as insulators in combined electrical and chemical environments.

The sheet format in GF15 is used for gaskets in flange joints with higher pressure or higher temperature, for slide plates in ovens and process lines, valve seats in ball valves, wear plates in chemical pumps and as lining in reactors and tanks where both chemical resistance and dimensional stability are needed. In the energy industry, GF15 gaskets are common in steam and hot water flanges, where the low creep properties make the torque requirement on the bolts hold better over time. In the food and pharmaceutical industry, GF15 is used as slide support and sealing part because the inert nature of the PTFE base resin fits strict cleanliness requirements.

In machining, the glass fiber is what decides the tool choice. Carbide lasts longer than HSS, and waterjet is a good alternative for complicated contours. The sheet can be milled, turned, drilled, punched and waterjet cut without trouble. Cutting fluid is not needed, but air cooling keeps the tool cool on harder cuts. The material cannot be welded or bonded conventionally; mechanical fasteners or etching is the way to go. When mounting gaskets, retightening should be done after heating cycles, since the material settles slightly. Punching works fine in thinner thicknesses; for thicker parts, CNC milling gives better edges and dimensional accuracy.

Thickness is chosen to suit the application. Thin sheets suit punched flange gaskets, medium ones slide supports and wear strips, thicker ones turned ring parts and block milled components. PTFE sheets are press sintered and have a homogeneous structure all the way through, so the surface quality after machining comes out even also where deep pockets have been milled out of the material. For gaskets, it is also worth knowing that GF15 settles slightly less under the first torque than pure PTFE, which is part of the point of the grade.

Storage is indoors in a normal warehouse environment. PTFE GF15 is insensitive to UV, ozone, moisture and most storage conditions found in industry and workshops. Sheets are stacked flat and supported evenly so they do not bow over time; for large areas and thin thicknesses that matters even more. The material needs no special pretreatment before machining beyond normal acclimatization when moving between a cold and a warm store. For customers working to strict cleanliness requirements, such as the semiconductor or pharmaceutical industry, there are PTFE grades with certified batch traceability; it is worth checking whether the application calls for that before a specific dimension is ordered.

If you want to compare grades within the family: pure PTFE for minimal friction without load, GF10 as the lighter mechanical grade, GF15 in the middle and GF25 where the load is higher still. CP25 with carbon fiber is an alternative when dynamic wear resistance matters most. Get in touch if you want to talk dimensions or a specific sealing application.

With 1200x1200 mm in natural you get several dimensionally stable slide pads out of one sheet.