Loctite 577 Medium Strength Thread Sealant 50ml

Loctite 577 is a one-component, yellow, medium strength anaerobic thread sealant in paste form. It is a dimethacrylate ester designed for the locking and sealing of metal threaded pipes and fittings.

Henkel states it is particularly suitable for stainless steel without surface activation. It cures in the presence of minor surface contamination from cutting, lubrication and anti-corrosion fluids, and has gap performance to 0.25 mm.

Where this product is used

• Locking and sealing metal threaded pipes and fittings
• Stainless steel threads, without surface activation
• Threads with minor contamination from cutting, lubrication or anti-corrosion fluids
• Threads where gap performance to 0.25 mm (0.01 in) is needed
• Gas fittings where the regional approvals listed in the specification apply

Features

• Medium strength, 33 N·m breakaway on M10 steel
• One component, no mixing
• Yellow paste, high viscosity and thixotropic
• Fluorescence positive under UV light, useful for inspection
• Anaerobic cure, with an activator as secondary cure
• Seals instantly to moderate pressures when properly tightened
• Gap performance to 0.25 mm (0.01 in)

Key specifications

Available sizes

Selecting the right option

Loctite 577 is the medium strength paste. For a medium strength liquid see Loctite 542 Medium Strength Thread Sealant. For low strength see Loctite 567 PST Low Strength Thread Sealant or Loctite 565 PST Thread Sealant 50ml.

Using it

Apply a 360 degree bead to the threads of the male fitting, leaving the first thread free. Activator SF 7471 or SF 7649 is the secondary cure.

Fittings seal instantly to moderate pressures. For maximum pressure and solvent resistance, allow a minimum of 24 hours to cure.

Storage and handling

Store unopened in a dry location. Optimal storage is between 8 °C and 21 °C. Storage below 8 °C or above 28 °C can adversely affect the properties of the product.

Limits and safety

Not recommended for pure oxygen or oxygen-rich systems, or as a sealant for chlorine or other strong oxidising materials. Plastics can stress crack. The Henkel data sheet states no general service temperature range: the only working temperature given is -10 to 135 °C within the Australian Gas Association approval, and cold strength was tested to -75 °C.

Frequently asked questions

Is Loctite 577 approved for gas?

Henkel states it is approved by the Australian Gas Association (certificate 4787, Class III, 2000 kPa, working temperature -10 to 135 °C) and is an EN 751-1 class H compound with DVGW certification. The AGA and GASTEC approvals are regional.

Does Loctite 577 work on stainless steel?

Yes, without surface activation, according to Henkel. Henkel names activator SF 7471 or SF 7649 as the secondary cure.

How long before pressure testing with Loctite 577?

Fittings seal instantly to moderate pressures. Allow a minimum of 24 hours for maximum pressure and solvent resistance.

What is the breakaway torque of Loctite 577?

33 N·m on M10 steel and 15 N·m on M10 stainless steel after 24 hours at 22 °C (ISO 10964).

Is Loctite 577 suitable for hydrogen?

The data sheet lists GASTEC QA AR-214 and Hydrogen Certified Adhesive. Henkel marks the approval as regional, so confirm it for your application.

What temperature range does Loctite 577 handle?

The data sheet states no general service range. The working temperature in the AGA approval is -10 to 135 °C, and cold strength was tested to -75 °C.

Related products

See also: Loctite 542 Medium Strength Thread Sealant, Loctite 567 PST Low Strength Thread Sealant, Loctite 565 PST Thread Sealant 50ml, Loctite 569 Low Strength Thread Sealant 50ml, Loctite 5770 High Temperature Thread Sealant 50ml.