If you’re experiencing extremely slow or incomplete cure times when using anaerobic sealants on parts made of materials like stainless steel, aluminum, zinc, or anodized/plated surfaces, the issue is the low catalytic activity of these “passive metals.”
Anaerobic sealants are designed to cure rapidly in the absence of oxygen and in the presence of active metal ions (like those found in steel, iron, copper, and brass). Passive metals don’t readily provide these ions, which dramatically slows or even halts the polymerization process.
The solution is two-fold: Surface Activation and Selecting the Right Flexible Sealant for your application.
1. The Essential Fix: Using an Anaerobic Activator
The most reliable way to speed up the cure on passive metals is to introduce an external source of the metal ions needed for the reaction.
- How it Works: An anaerobic activator (or primer) is a solvent-based liquid containing copper ions. When applied to one or both surfaces, the solvent evaporates, leaving a thin layer of active ions that act as the necessary catalyst for the sealant to cure.
- The Process: Apply the activator to one surface, allow the solvent to flash off (dry), and then apply the sealant (like Incure HeatGrip 504) to the other surface before assembly. This will bring the cure speed back in line with what you’d expect on an active metal.
- Best Practice: Always use an activator when working with stainless steel, aluminum, or plated parts to ensure a full and timely cure.
2. Choosing the Best Flexible Sealant: Incure HeatGrip™ 504
For general-purpose sealing on these rigid but passive machined flanges, we recommend Incure HeatGrip™ 504 Flexible General Purpose Gasket Sealant.
While the activator is the key to solving the slow-cure problem, the HeatGrip 504 is the ideal sealant to pair with it due to its balanced properties:
| Feature | Benefit for Passive Metal Applications |
| Flexible Cure Layer | Cures into a flexible plastic layer (up to 150°C), allowing the seal to flex with minor joint movementsor thermal expansion common in aluminum and stainless assemblies, preventing leaks. |
| General Purpose Formula | A highly versatile formulation with a working gap fill up to 0.25 mm, which is perfect for most precision-machined flanges. |
| Clear Visual ID | The purple color simplifies identification, making quality control easier and ensuring you haven’t mistakenly used a non-anaerobic product. |
3. Special Consideration for Aluminum: HeatGrip™ 508
If your primary application is with aluminum flanges (a passive metal), you may consider Incure HeatGrip™ 508 Flexible Anaerobic Flange Sealant for Aluminum.
While it also requires an activator for a fast cure, the 508 is specifically engineered to:
- Offer easier disassembly and clean-up, a crucial benefit when working with softer aluminum components.
- Provide a higher compressive strength (7.8 N/mm2) for robust sealing on critical, load-bearing aluminum parts.
In summary: Don’t let slow cure times stall your project. Use an activator with the Incure HeatGrip 504 for fast, reliable seals on all rigid metal flanges, including those made of passive metals.