What Is LOCTITE® DRI STS Thread Sealant Coating for Fasteners and Fittings?
LOCTITE® DRI STS is a medium-strength, pre-applied adhesive and thread sealant coating designed for threaded fasteners and fittings. The two-component acrylic coating uses methacrylate ester technology and provides both locking and sealing performance after assembly.
The dry-to-the-touch coating remains inert on the part until assembly. As the fitting or fastener is installed, a microencapsulated activator is released, initiating the anaerobic curing process. The resin fills voids within the threads and cures to securely lock and seal the assembly.
LOCTITE DRI STS also provides high lubricity to help minimize friction and create a more controllable torque-tension relationship. This makes it particularly useful for straight-threaded assemblies that require dependable locking, sealing, and resistance to loosening caused by vibration.
Key Benefits
- Medium-strength locking and sealing for threaded assemblies
- Pre-applied, dry-to-the-touch coating for ready-to-use fasteners and fittings
- Helps prevent loosening caused by vibration
- Seals thread voids after curing
- High lubricity helps minimize friction during assembly
- Supports a more controllable torque-tension relationship
- 10-minute fixture time
- Four-year on-part life
- Good resistance to motor oil, gasoline, brake fluid, water/glycol, and tested solvents
- Suitable for a variety of steel and coated-steel fastener combinations
- Can be applied to threaded components in automated processing environments
LOCTITE DRI STS is not recommended for copper or brass surfaces.
Where Is LOCTITE® DRI STS Used?
| Application | How LOCTITE DRI STS Supports the Assembly |
|---|---|
| Straight Threaded Assemblies | Locks and seals straight threaded connections while helping prevent vibration-related loosening |
| Ring Gear Bolts | Provides locking and sealing performance for threaded bolt assemblies |
| Carburetor Screws | Helps secure threaded connections against loosening |
| Transmission Nuts & Bolts | Provides locking, sealing, and vibration resistance for transmission assemblies |
| Head Bolts | Creates a cured locking and sealing layer within the threads |
| Truck Axle Bolts | Helps maintain threaded connections in assemblies exposed to vibration |
| Tower Bolts | Provides medium-strength locking for straight threaded assemblies |
| Pipe Plugs & Fittings | Fills thread voids to help lock and seal the assembled connection |
Industries & Markets
| Industry or Market | Typical Application |
|---|---|
| Automotive | Ring gear bolts, carburetor screws, transmission fasteners, and head bolts |
| Heavy-Duty Vehicle Components | Truck axle bolts and other threaded assemblies exposed to vibration |
| Power Transmission & Drivetrain | Transmission nuts, bolts, and related threaded components |
| Industrial Manufacturing | Straight threaded assemblies requiring both locking and sealing |
| Fluid Handling Components | Pipe plugs and fittings requiring sealed threaded connections |
| Fastener Manufacturing & Processing | Pre-applied coating of threaded components prior to final assembly |
| High-Volume Assembly | Pre-coated fasteners that can arrive dry-to-the-touch and ready for installation |
Technical Highlights
| Property | LOCTITE DRI STS Performance |
|---|---|
| Technology | Acrylic |
| Chemical Type | Methacrylate ester |
| Components | Two-component system |
| Cure Type | Anaerobic |
| Application | Thread sealing |
| Strength Classification | Medium strength |
| Fixture Time | 10 minutes |
| On-Part Life | 4 years |
| Breakaway Torque – 24 Hours | ≥17.0 N·m (≥150.4 lb·in.) on tested 3/8 × 16 phosphate-and-oil fasteners |
| Breakaway Torque – 72 Hours | ≥22.6 N·m (≥200 lb·in.) on tested 3/8 × 16 phosphate-and-oil fasteners |
| Breakloose Torque – Anti-Rust Steel | 45 N·m |
| Breakloose Torque – Zinc-Plated Steel | 42 N·m |
| Breakloose Torque – Magni 554-Plated Steel | 39 N·m |
| Coefficient of Friction | 0.11–0.15 on specified tested fastener combinations |
Chemical Resistance
LOCTITE DRI STS was tested for chemical and solvent resistance after curing for 72 hours at 22°C. Results below represent the percentage of initial breakaway strength retained following exposure.
| Chemical or Environment | Test Temperature | 100 hours | 500 hours | 1,000 hours |
|---|---|---|---|---|
| Motor Oil | 125°C | 105% | 105% | 102% |
| Motor Oil | 87°C | 119% | 124% | 126% |
| Unleaded Gasoline | 22°C | 109% | 116% | 118% |
| Brake fluid | 22°C | 105% | 109% | 110% |
| 1, 1, 1 Trichloroethane | 22°C | 103% | 116% | 115% |
| Water/Glycol 50/50 | 87°C | 124% | 116% | 110% |
Need a Pre-Applied Solution for Locking and Sealing Threaded Assemblies?
LOCTITE® DRI STS provides a ready-to-use solution for straight threaded fasteners and fittings that require dependable locking, sealing, and resistance to vibration. Its dry-to-the-touch, pre-applied coating eliminates the need to apply a liquid product during final assembly, while high lubricity helps provide a more controllable torque-tension relationship.
