In the demanding world of manufacturing, a leak is more than just a nuisance; it can lead to costly downtime, wasted resources, safety hazards, and compromised product quality. Flange connections, critical points in fluid and gas handling systems, require impeccable sealing to ensure operational integrity. While traditional gaskets have long been the standard, modern anaerobic flange sealants offer a superior alternative, providing robust, long-lasting, and highly reliable seals.

At Incure, we empower manufacturers and industry professionals with the knowledge and high-performance adhesive solutions necessary to tackle complex sealing challenges. Understanding the proper application of flange sealants is key to harnessing their full potential and achieving truly leak-free systems.

Why Choose Anaerobic Flange Sealants Over Traditional Gaskets?

Traditional cut gaskets work by compressing between two flange surfaces. However, they are prone to relaxation over time, can extrude under pressure, and often fail to fill microscopic surface imperfections. This can lead to persistent leaks, especially in dynamic environments or under thermal cycling.

Anaerobic flange sealants, on the other hand, offer distinct advantages:

• Formed-in-Place (FIP) Sealing: They fill every microscopic void and imperfection between rigid metal flanges, creating 100% surface-to-surface contact. This eliminates leak paths that traditional gaskets often leave open.
• No Relaxation or Shrinkage: Once cured, anaerobic sealants form a tough, thermoset plastic that will not relax, shrink, or creep over time, maintaining consistent clamp load.
• Enhanced Strength and Durability: They add structural integrity to the joint, increasing its resistance to vibration, shock, and thermal expansion/contraction.
• Corrosion Prevention: By displacing air and moisture, they prevent fretting and galvanic corrosion at the flange interface, extending component lifespan.
• Simplified Inventory: A single tube of anaerobic flange sealant can replace dozens of different pre-cut gasket sizes and shapes, streamlining inventory management.
• Ease of Disassembly (when required): While providing high performance, many anaerobic flange sealants are designed for easy disassembly with standard tools, facilitating maintenance.

A Step-by-Step Guide to Applying Anaerobic Flange Sealant

Achieving optimal performance from anaerobic flange sealants hinges on proper surface preparation and application. Follow these best practices for a reliable, leak-free seal:

Step 1: Surface Preparation – The Foundation of a Strong Seal

This is arguably the most critical step. Anaerobic adhesives require clean, active metal surfaces for proper curing and adhesion.

• Thorough Cleaning: Remove all traces of old gasket material, previous sealants (including RTV silicones), paint, oil, grease, dirt, and rust. Use a suitable solvent cleaner/degreaser that leaves no residue.
  • Practical Insight: Avoid using razor blades or abrasive wire brushes that can scratch or gouge the flange surfaces, as these imperfections can create new leak paths. Plastic scrapers or specialized gasket removers are preferred.
• Inspect Flange Surfaces: Examine the flanges for any nicks, burrs, warps, or significant damage. While anaerobic sealants can bridge minor imperfections, severe damage may require machining or repair for optimal results. For rigid machined flanges, the typical gap-filling capability for anaerobic sealants is up to 0.5 mm (0.020 inches). For larger or irregular gaps, a different sealant technology (e.g., specific RTV silicones) might be more appropriate.
• Drying: Ensure both flange surfaces are completely dry before application.

Step 2: Activating (If Necessary) – Ensuring Rapid Cure

Most anaerobic sealants will cure on active metal surfaces (e.g., steel, brass, copper). However, on inactive metals (e.g., aluminum, stainless steel, plated surfaces) or in low-temperature environments, an anaerobic activator may be required to ensure a fast and complete cure.

• Apply Activator (if needed): If using an activator, apply a thin, even coat to one of the flange surfaces and allow it to dry completely according to the manufacturer’s instructions.

Step 3: Sealant Application – Precision is Key

• Apply a Continuous Bead: Dispense a continuous bead of anaerobic flange sealant onto one of the prepared flange surfaces. The bead should be placed close to the inner rim of the flange and encircle all bolt holes.
  • Actionable Advice: For larger flanges, or in automated processes, dispensing equipment or a roller can ensure a consistent and even application. Avoid applying too much sealant; excess material can squeeze out and may need to be wiped away.
• Fill Imperfections: Ensure the sealant fills any minor surface imperfections or scratches on the flange face.

Step 4: Assembly – Prompt and Controlled

• Immediate Assembly: Assemble the mating flanges as soon as possible after applying the sealant. This ensures the sealant is confined in the absence of air, initiating the cure process.
• Minimal Lateral Movement: Avoid excessive lateral movement when bringing the flanges together, as this can smear the sealant and compromise the seal.
• Tighten Bolts: Torque the bolts to the manufacturer’s specified values in a cross-pattern sequence. This ensures even pressure distribution across the flange joint. While some anaerobic sealants provide an instant low-pressure seal, full cure and maximum strength are achieved after the specified cure time (typically 24 hours at room temperature).

Step 5: Curing and Testing – Patience for Performance

• Allow for Cure: Allow the assembly to cure for the recommended time (as per the product’s Technical Data Sheet) before putting it into full service. This ensures the sealant achieves its maximum strength and pressure resistance.
• Wipe Away Excess: Any excess sealant that squeezes out of the joint and remains exposed to air will not cure. This can be easily wiped away with a cloth.
• Leak Testing: Perform appropriate pressure or leak testing as part of your quality control process to confirm the integrity of the sealed joint.

How Incure Supports Your Flange Sealing Projects

At Incure, our commitment goes beyond providing high-quality products. We aim to be a comprehensive resource for professionals seeking to optimize their manufacturing and maintenance operations.

• Specialized Flange Sealant Formulations: We offer a range of anaerobic flange sealants tailored for different applications, gap tolerances, temperature requirements, and chemical resistances, ensuring you have the right solution for every rigid metal flange.
• Technical Guidance: Our experienced team can provide detailed technical support, helping you select the ideal Incure product for your specific application and guiding you through best practices for surface preparation, application, and curing.
• Process Optimization Insights: We provide actionable advice on integrating anaerobic sealants into your existing assembly lines, including tips for automated dispensing, to enhance efficiency and reduce costs.
• Commitment to Reliability: Every Incure product undergoes rigorous quality testing to ensure consistent performance, giving you confidence in the long-term integrity of your critical flange connections.

Elevate Your Sealing Standards

By embracing advanced anaerobic flange sealants and adhering to proper application techniques, manufacturers can significantly enhance the reliability, longevity, and performance of their bolted flange assemblies. Eliminate leaks, prevent corrosion, and streamline your production processes.

Connect with Incure today to explore our comprehensive range of flange sealing solutions and discover how we can help you achieve superior sealing integrity in your manufacturing projects.