Nothing is more frustrating than finishing a gasketing job, waiting the full cure time, and discovering you still have a leak. When an anaerobic flange sealant fails, it is almost never the fault of the product itself, but rather a misstep in preparation, selection, or application.

Successfully sealing a joint with a product like the Incure HeatGrip series requires meeting several non-negotiable chemical and mechanical conditions. If you still have leaks, your seal is compromised by one or more of these critical factors:

1. Surface Contamination (The #1 Killer)

• Problem: The sealant cannot touch bare metal due to a film of oil, grease, dirt, old gasket residue, or incompatible cleaning solvent residue. This contamination chemically inhibits the cure and prevents adhesion.
• Leak Result: The sealant remains liquid or only partially cured, resulting in immediate leakage under pressure.
• The Fix: Meticulous cleaning. Use a residue-free solvent (like acetone or IPA) and wipe until your cloth comes away spotless.

2. Wrong Sealant Chemistry (Gasket Mismatch)

• Problem: You used an anaerobic sealant on a joint that requires a different chemistry. Anaerobics are for rigid, precision-machined metal flanges with a gap of less than 0.25 mm.
• Leak Result: If the parts are stamped, cast, or visibly warped (gap $ > 0.25\text{ mm}$), the sealant cannot fill the space, and trapped oxygen prevents cure.
• The Fix: Measure your gap. For large gaps or non-rigid surfaces, switch to an RTV Silicone Gasket Maker.

3. The Cure Was Slowed or Stopped

• Problem: The metal was a passive alloy (aluminum, stainless steel) or the environment was too cold (<5∘C), slowing the cure far beyond the expected time.
• Leak Result: The assembly was put back into service before the sealant achieved its full 5.2 N/mm2 compressive strength, leading to blowout or seepage.
• The Fix: Use an Anaerobic Activator. Always use a primer on passive metals or in cold conditions to accelerate the cure. Wait the full 24 hours for full cure before subjecting the joint to full operational pressure.

4. Improper Torque Applied

• Problem: Under-torquing prevents the flanges from mating tightly, trapping air and preventing cure. Over-torquing warps the flange, creating uneven gaps and high-stress points that crack the seal.
• Leak Result: The mechanical integrity of the joint is compromised, causing the seal to fail under dynamic stress or pressure.
• The Fix: Use a calibrated torque wrench and follow the manufacturer’s specified cross-hatch sequence and values to ensure even, correct clamping force.

5. Coating Barrier Present

• Problem: A barrier layer (paint, lacquer, PTFE tape, or old gasket residue) was present, preventing the sealant from making the crucial direct contact with the bare metal catalyst.
• Leak Result: The sealant remains liquid against the barrier, and the assembly leaks immediately.
• The Fix: Scrape down to bare metal. Remove all coatings and old materials entirely before cleaning and applying the sealant.

Incure HeatGrip™ 504 Flexible General Purpose Gasket Sealant

To minimize the chances of a chemical failure (provided the mechanical steps are followed), we recommend Incure HeatGrip™ 504 Flexible General Purpose Gasket Sealant.

The 504 is the best choice because:

• Flexible Assurance: Its semi-flexible cure layer better manages the minor imperfections and stresses (vibration, thermal expansion) common in real-world assemblies, giving you a wider margin of error than a fully rigid sealant.
  
• Visual Confirmation: The purple color helps ensure you apply a continuous, even bead without voids (preventing under-application) and helps with visual cleanup (preventing over-application).

If you are still getting leaks after fixing one issue, re-check the list—a failed seal is often caused by a combination of two or more of these factors.