LOCTITE 577 General-Purpose Thread Sealant for Metal Pipes, Stainless Steel and Industrial Fittings

LOCTITE 577 Thread Sealant Benefits

LOCTITE 577 Thread Sealant provides an immediate seal against moderate pressure after properly tightened fittings are assembled. Unlike PTFE tape and some conventional sealing materials, the cured compound does not creep, shrink or shred inside the piping system. This helps create a cleaner and more dependable threaded connection while reducing the possibility of loose sealing fragments entering valves, pumps or fluid passages.

The product cures on both active metals, including brass and copper, and passive metals such as stainless steel and plated surfaces. It is particularly suitable for stainless-steel fittings and normally does not require prior surface activation under standard conditions. The formulation also tolerates minor residues of cutting oil, lubric conditions. The formulation also tolerates minor residues of cutting oil, lubricating oil, corrosion-prevention fluid and selected industrial cleaners.

Its medium cured strength allows most fittings to be dismantled using standard hand tools. This makes the product suitable for industrial pipe systems that require secure sealing together with future maintenance access.

LOCTITE 577 Thread Sealant Applications

LOCTITE 577 Thread Sealant is recommended for straight-to-straight and straight-to-taper threaded metal connections. Typical applications include pumps, compressors, gearboxes, hydraulic equipment, pneumatic systems, process machinery, water lines, gas installations and general industrial fluid-handling equipment.

The sealant can be used on steel, stainless steel, brass, copper and compatible plated fittings. Its published gap-filling performance reaches approximately 0.25 mm, allowing it to seal coarse threads and fittings with practical manufacturing clearances. Plastic pipes and thermoplastic fittings require separate compatibility testing because anaerobic materials may contribute to stress cracking in sensitive plastics.

LOCTITE 577 Thread Sealant Technical Properties

LOCTITE 577 Thread Sealant is based on dimethacrylate ester technology and appears as a yellow fluorescent paste before curing. Its Brookfield viscosity is approximately 24,500 mPa·s at 20 rpm and 100,000 mPa·s at 2.5 rpm, demonstrating its strongly thixotropic, non-running application behavior.

After curing for 24 hours at 22°C, published breakaway torque on M10 steel nuts and bolts is approximately 33 N·m. Representative values include approximately 23 N·m on brass and 15 N·m on stainless steel under the stated test conditions. The listed continuous operating-temperature range is approximately -55°C to 150°C.

The cured material demonstrates resistance to motor oil, petrol, brake fluid, ethanol, acetone, water-glycol mixtures, biodiesel and diesel exhaust fluid in laboratory testing. These figures are typical technical values rather than guaranteed purchasing specifications. Performance depends on the fitting material, thread geometry, clearance, tightening torque, surface condition and curing environment.

How to Apply LOCTITE 577 Thread Sealant

Clean the internal and external threads and allow them to dry. When inactive metals, unusually large gaps, low temperatures or slow curing conditions are present, LOCTITE SF 7471 or LOCTITE SF 7649 Activator may be applied and allowed to dry before sealing.

Apply a continuous 360-degree bead around the leading male threads while leaving the first thread free. Work the paste into the thread profile to fill the voids. Larger threads may require additional material on the female fitting. Assemble and wrench-tighten the connection according to the equipment manufacturer’s recommendations.

Properly tightened fittings provide an immediate moderate-pressure seal. Allow at least 24 hours of curing before exposure to maximum pressure or demanding solvents. Most cured assemblies can be removed with hand tools; large or heavily engaged fittings may require localized heating before disassembly.

Why Choose LOCTITE 577 Thread Sealant?

LOCTITE 577 Thread Sealant combines immediate low-pressure sealing, contamination tolerance, strong chemical resistance and dependable curing on active and passive metals. Its thixotropic consistency, medium removal strength and broad industrial usability make it a practical alternative to sealing tape for stainless-steel and general metal pipe systems.

Review the official Henkel LOCTITE 577 Technical Data Sheet and current Safety Data Sheet before qualification or production use. Explore our industrial thread sealants for additional hydraulic, pneumatic, gas and fluid-processing sealing solutions.