LOCTITE 542 – Medium-strength thread sealant

LOCTITE 542 – Medium strength thread sealant for fine metal threads and pipe fittings

Product Description

LOCTITE 542 is a low-viscosity, one-component sealant based on dimethacrylate ester, specifically designed for securing and sealing fine metal threads, fittings, and pipe connections. Anaerobic curing begins upon contact with metal and in the absence of air between closely fitting threaded surfaces. This creates a permanent, vibration- and pressure-resistant bond that reliably prevents even the smallest leaks and the loosening of the fitting.

Due to its thixotropic consistency, LOCTITE 542 adheres precisely to the threads after application, preventing runoff and ensuring even distribution within the thread gap. The product provides a medium-strength seal, allowing connections to be loosened again with standard hand tools if necessary. LOCTITE 542 is resistant to numerous chemicals, oils, fuels, as well as coolants and brake fluids, and remains reliably tight even under temperature fluctuations or heavy loads.

This brown liquid sealant is particularly suitable for use in hydraulic and pneumatic systems, in industry, mechanical engineering, and throughout plant construction. Thanks to its versatile compatibility and ease of application, LOCTITE 542 is an indispensable product for any professional maintenance and assembly of metal pipes and fittings.

Product properties

• Color: brown
• Strength: medium, disassemblable with hand tools
• Chemical basis: Dimethacrylate ester, one-component, anaerobic curing
• Viscosity (25 °C): 400–800 mPa·s (at 20 rpm), thixotropic
• Breaking moment (M10 steel): 15 Nm
• Further torque (M10 steel): 9 Nm
• Compressive shear strength (steel): ≥6.5 N/mm²
• Temperature range: -55 °C to +150 °C
• Resistance: Motor oil, gasoline, brake fluid, water/glycol, ethanol, acetone
• Curing: firm to the touch after a few minutes, final strength after 24 hours
• Storage: optimal at 8–21 °C, unopened shelf life at least 24 months
  
  

Suitable materials

• Metallic pipe threads and fittings
• Steel, stainless steel, brass, copper
• Coated and galvanized metal surfaces
• Not recommended for plastics (especially thermoplastics)
  
  

Typical application areas

• Sealing of fine threads and pipe fittings
• Securing fittings in hydraulic and pneumatic systems
• Thread sealing in plant and mechanical engineering
• Maintenance and servicing of industrial plants
• Applications in heating, plumbing and refrigeration systems
• Sealing of threaded fittings and brass screw connections
  
  

Processing instructions

1. Preparation: Thoroughly clean and dry the threads (e.g. with LOCTITE cleaner); for passive surfaces, use an activator if necessary (e.g. LOCTITE 7471 or 7649).
2. Instructions: Apply the product in a 360° ring shape to the beginning of the external thread (leave the first thread free), and if necessary also to the internal thread.
3. Assembly: Screw in the fitting as usual and tighten with a tool.
4. Sealing effect: Immediate sealing effect against low pressures, complete chemical and mechanical resistance after 24 hours.
5. Disassembly: Can be removed with standard hand tools; for larger threads, local heating may be necessary (approx. 250 °C).
6. Cleaning: Hardened product can be removed by soaking in solvent and mechanical removal.

Note: LOCTITE 542 was specifically developed for metal threads and is not suitable for use on plastic or non-metal threads.