Expand-A-Lock is a unique pre-applied microencapsulated expanding threadlocking and sealing compound. Expand-A-Lock increases in volume 20 to 50% on installation, penetrating the gaps in fastener threads that are typically unfilled by conventional threadlockers. Pre-Applied to fasteners, Expand-A-Lock arrives dry to the touch and ready for assembly.

How it Works

Expand-A-Lock contain a microencapsulated epoxy resin and expanding compounds suspended in a hardener. The forces of engagement crush the microscopic capsules of epoxy resin and expansion agent, mixing the separate reactant components, and initiating a chemical reaction. As the reaction is taking place, the material expands, filling the fastener thread gaps while hardening.


Problem Solver

Many threadlockers fail when used in less than optimal conditions, such as misfit parts or with threadformed screws. Because of its expansion properties, Expand-A-Lock can overcome these limitations.

Surface Insensitive

Expand-A-Lock is compatible with most fastener sizes, configurations, materials and finishes. Its epoxy formulation ensures that a strong reliable lock and seal are formed.

Resists Chemicals

The cross-linked molecular structure of Expand-A-Lock makes it one of the most resistant types of adhesives. Oil, gasoline, salt spray, acids, solvents, and water have virtually no effect on parts when introduced after a final cure has been achieved.

Strongest Lock Available

Expand-A-Lock has been shown to provide some of the highest break away torques of all our reactive threadlocking materials.

Low Prevailing on Torque

Compared to patch threadlockers, Expand-A-Lock assembles easily with common hand tools.

Surpasses IFI Standards

Expand-A-Lock meets or exceeds all torque requirements of IFI 125, IFI 525, as well as automotive adhesive coated fastener performance specifications.


  • Saves Time: Fasteners coated with Expand-A-Lock can be automatically fed through standard feeding devices – speeding up your process and improving productivity.
  • Saves Money: The bulk pre-application of Expand-A-Lock to fasteners is less expensive than hand applying bottled thread locking compounds at the point of assembly. It also eliminates the need for costly lock washers, cotter pins or castellated nuts.
  • Quality Control: Pre-Applied Expand-A-Lock fasteners are coated to specification, ensuring consistent performance, unlike the variation from hand applying bottled products
  • Reliability: Under most operating conditions, Expand-A-Lock is unaffected by vibration or reversal of stress and greatly reduces the need to re-tighten fasteners.


  • Under typical conditions, Expand-A-Lock has a fixture time of 15 minutes with a full cure in 24 hours.
  • Expand-A-Lock is normally applied one to three threads back from the end of a fastener to assure ease of starting.
  • It is recommended that Expand-A-Lock is not reused.
  • As with all our Pre-Applied products, ND Industries can apply Expand-A-Lock to your fasteners at any one of our regional service centers, or we can supply you with completed pre-applied fasteners.
  • *Shelf life of un-activated part is 1 year when stored in a dry, cool environment.

Expand-A-Lock Competes With

  • N/A – Expand-A-Lock is a ND Industries exclusive product.


Use Expand-A-Lock to seal critical applications where shock, vibration and fluid pressure cause the fastener to loosen or the joint to leak. Marine Ride Plates, Head Bolts, Engine Plugs and bolts, Pipe Fittings, Air fitting connectors.

Compatible Fasteners

External Threads:Internal Threads:Rivets:
Banjo Bolts, Hex Bolts, Flange Bolts, Wheel Bolts, Machine Screws, Cap Screws, Wood Screws, Sheet Metal Screws, Self Drilling Screws, Shoulder Bolts, Fully Threaded Studs, Double Ended Studs, Singled Ended Studs, Press-In Captive Studs, Carriage Bolts, Lag Bolts, Socket Screws, Set Screws, Eye Bolts, Eye Lags, J-Bolts, U-Bolts, Elevator Bolts, Hangar Bolts, Perforated Base Studs, Through Hole Weld Studs.Flange Nuts, Hex Body Clinch Nuts, Prevailing Torque Nuts, Floating Nuts, Hollow Bolts, Insert Nuts, Lock Nuts, Weld Nuts, Barrel Nuts, Chicago Bolts, Jam Nuts, Wing Nuts, Square Nuts, Self-Locating Projection Weld Nuts (WN/WNS), Spot Weld Nuts, Projection Weld Nuts, Bridge Spot Weld Nuts, Tab Spot Weld Nuts, Square Projection Weld Nuts, Flange Weld Projection Nuts, Stamped Flange Weld Nuts, Spot Weld Cage Nuts.N/A

Don’t see your parts on this list? We process thousands of different types of fasteners and depending on the quantity will gladly look at whether we can accommodate yours as well.

Technical Data

ProcessColorPrimary UsePrevailing On TorqueBreakaway TorqueTemp MinTemp MaxLubricityPressure Resistance**
Expand-A-LockGreenHeavy Duty LockExceeds IFI 125 & IFI 525-65°F (-54°C)300°F (150°C)Medium> 115 PSI

**Coated parts assembled into aluminum block and submersed in the test fluid and heated for 30 days then tested at temperature for sealing and tested for breakaway torque when cooled. Assembled parts tested at 793 kPa (115 PSI).


Particular formulations of Expand-A-Lock meet or exceed the performance requirements of the following specifications and/or standards:

Spec ForSpec NumberND ProcessND Material
DINDIN 267 Part 27Expand-A-LockExpand-A-Lock

Safety, Technical & Process Data Sheets

Process NameMaterialSafety Data Sheet (Applied)Technical Data Sheet (Applied)Process Data Sheet
Expand-A-Lock®EL0105Expand-A-Lock EL0105 (Applied)
Expand-A-Lock - TDS (Applied)Expand-A-Lock - PDS
Increase product quality while saving time and money with Pre-Applied adhesives and sealants.