How to Install PTFE Gaskets Correctly
Proper gasket installation is critical for achieving a leak-free seal. Follow this step-by-step guide to install PTFE gaskets correctly and avoid common mistakes that lead to premature failure.
Step 1: Inspect Flange Surfaces
Clean both flange faces thoroughly with a wire brush or solvent to remove old gasket material, rust, and debris. Check for surface defects such as scratches, pitting, or warping. The flange surface finish should meet the gasket manufacturer specifications (typically 125-250 RMS for PTFE gaskets).
Step 2: Verify Gasket Specifications
Confirm the gasket matches the required specifications: correct material (virgin or filled PTFE), proper dimensions (inner diameter, outer diameter), correct thickness, and appropriate pressure class rating. Never use a damaged or creased gasket.
Step 3: Position the Gasket
Center the gasket carefully on the flange face. Do not use adhesives or sealants unless specifically recommended by the manufacturer. Ensure the gasket sits flat without wrinkles or folds. For large diameter gaskets, use alignment tools or temporary pins to maintain position.
Step 4: Tighten Bolts in Sequence
Use a calibrated torque wrench and follow the star-pattern (cross-pattern) tightening sequence. Tighten in at least 3 passes: first to 30% of target torque, second to 60%, and final to 100%. This ensures even compression and prevents gasket damage from uneven loading.
Step 5: Final Inspection
After 24 hours of operation, re-torque the bolts to compensate for gasket relaxation (a common characteristic of PTFE). Check for leaks using appropriate methods (visual inspection, pressure test, or leak detection spray). Document the installation for maintenance records.