PTFE thread seal tape

Wrap in the tightening direction, clockwise viewed from the thread end for right-hand threads, so the tape does not unwind on assembly. Typically 3 to 5 wraps, leaving the first thread bare so shreds do not enter the line. Large or coarse threads may need more.

By common convention white is general purpose for water and air, yellow is a thicker gas-line tape, and pink is a heavy tape for larger water threads. Colour is a market convention, not a global mandatory standard. Read the thickness and density on the reel rather than relying on colour.

It should not be. Parallel G threads seal on a washer or gasket at the face, and tape cannot build up the interference that a taper gives. PTFE tape works only on taper threads such as R, Rc or NPT.

Only tape certified oxygen-clean, usually green, should be used. Standard tape can carry residual processing lubricant, creating a fire risk in high-pressure oxygen. Always follow the gas supplier's safety rules.

Only use PTFE tape approved for gas, usually thicker and denser and coloured yellow by convention in many countries. Thin general-purpose tape tears easily when tightened and is not reliable enough. Always leak-test with soapy water after assembly.

Common causes are too few wraps, wrapping against the thread direction, or backing the thread off after tightening to align it. Worn, rusted or mismatched tapered threads also leak. Once a joint has been backed off, take it apart, clean it and rewrap with fresh tape.

No, leave the first one or two threads bare so tape shreds do not enter the pipe. Loose PTFE fragments can jam valves, small orifices or nozzles. This matters especially in pneumatic and hydraulic systems.

PTFE handles roughly -200 to 260 degrees C and is inert to most chemicals, acids and solvents. That makes the tape usable on water, air, oil and many chemical lines. Practical limits usually come from pressure and thread condition rather than the material itself.