Round Rod in PTFE GF15 3000 mm natural

PTFE GF15 in round rod is a good starting material when you need to combine the chemical resistance and low friction of PTFE with a mechanical strength that pure PTFE does not reach. Fifteen percent glass fiber raises the compressive strength, cuts creep significantly and makes turned parts hold their dimension over time even under load. For bushings and seals that sit in flanged joints or in valves this is the difference between a component that cold flows out of the groove after a few months and one that holds year after year.

The density of the material is around 2.2 grams per cubic centimeter. The color is pale white to light gray white. The long term temperature is about 260 degrees and downward the material goes to cryogenic levels without becoming brittle, which makes it useful in both cold and hot process climates. The fire rating is V0. Friction stays low, somewhat higher than pure PTFE but in exchange for much better wear resistance and abrasion figures. The glass fiber also raises the dimensional stability during temperature swings and brings down the thermal expansion coefficient, which is valuable when bushings have to fit in metal housings across the whole working temperature.

Chemically PTFE GF15 is stable against nearly all process media. Acids, bases, solvents, ketones, alcohols, chlorinated hydrocarbons and oils do not affect the material. The limitation lies mainly in the sensitivity of the glass fiber to strong, hot caustic and hydrofluoric acid; in those cases pure PTFE or an inorganically filled grade is a better choice. Water absorption is negligible and the material is dimensionally stable even under full immersion, which makes it useful in pumps and in tank or reactor linings where the component is constantly wet.

The round rod format is turned into bushings, slide rings, guide sleeves, packing box sleeves, valve stem bearings and piston rings. In the process industry it is used in ball valves, dosing pumps, agitators and compressors where seals have to close tight without cold flowing out of the groove. The raised compressive strength lets GF15 take higher surface pressure than pure PTFE, which is valuable in flanged sealing joints and in components that have to stand mechanical clamping force. For plain bearings at low to medium PV values GF15 is often enough; at higher PV with dynamic movement CP25 with carbon fiber becomes a better choice.

Machining is done with carbide tools since the glass fiber wears on HSS. The rod is turned, drilled and milled without cutting fluid, but air cooling keeps tool and workpiece cool at heavier cuts. Sharp edges with a small radius give a fine surface finish. The material is not welded and not bonded conventionally; bushings are pressed or screwed into place. For a press fit the thermal expansion should be taken into the calculation so that the fit holds across the whole temperature range. PTFE round rods are press sintered and have a homogeneous structure, which makes the turned surface finish even at deep cuts and keeps the tolerances after machining.

The choice of diameter follows the part. Slim diameters suit valve stem sleeves and small bushings, medium sizes suit plain bearings and sealing rings, heavy ones suit turned flange parts and block shaped components where several parts can be taken from the same length. The material is stored indoors in a normal warehouse environment and is insensitive to UV and ozone during storage, but it is wise to keep the rods straight and support long lengths so that they do not bend over time.

For the design engineer PTFE GF15 in round rod format is often the starting point when pure PTFE has cold flow problems and you want to keep the low friction. It works in nearly all process media and has dimensional stability enough to hold tolerance bands down to hundredths of a millimeter when the part is correctly turned. For dimensions and tolerances that are not standard, rods can be cut to any length. The material is food approved in its basic form; for applications that require formal certification the specific batch has to be checked against the current standard. For strongly electrostatic environments it can be worth looking at the CP25 grade instead, since the carbon fiber gives some electrical dissipation that glass fiber does not.

When choosing grade: pure PTFE for minimal friction without mechanical load, GF10 as a lightly reinforced grade, GF15 when the pressure rises, GF25 when it rises further, and CP25 with carbon fiber when the component has to take both load and dynamic movement. Get in touch if you want to check a dimension or a specific bushing job.

The long 3000 mm rod in natural gives many dimensionally stable bushings out of a single piece.