Loctite 577

Loctite 577 is a high-performance, general-purpose thread sealant developed for sealing and locking metal pipe threads and fittings. It is designed to provide an instant, low-pressure seal, making it ideal for fast assembly work where reliability and efficiency are essential.

 
Suitable for both active and passive metals, it delivers consistent performance across a wide range of threaded connections without the need for additional activators in most applications.

Key Features

• Medium-strength thread sealing and locking compound 
• Suitable for all metal threaded pipe systems 
• Provides instant low-pressure sealing capability 
• Resistant to vibration, shock and thermal cycling 
• Excellent chemical and thermal resistance 
• Easy application with controlled flow properties 
• Cures on both active and inactive metals

Product Description

Loctite 577 is a premium anaerobic thread sealant designed for the locking and sealing of metal pipes, fittings and other threaded assemblies. Once applied between mating threads, it fills the microscopic gaps to form a durable seal while also preventing loosening caused by vibration or mechanical stress.

 
The formulation provides an instant low-pressure seal, allowing systems to be tested shortly after assembly, improving installation efficiency on site. It is engineered to resist creep, shrinkage and shredding, ensuring long-term joint integrity even under demanding operating conditions.

 
Recent formulation improvements have enhanced performance, delivering higher strength on contaminated surfaces, improved thermal resistance, and reliable curing on passive metals without the need for an activator. This makes it particularly effective in mixed-material installations and less-than-ideal site conditions.

 
Loctite 577 also offers excellent chemical resistance, making it suitable for use in a wide range of industrial, plumbing and mechanical systems where exposure to fluids, gases or temperature variation is expected. It is widely used across M&E, plumbing and process industries for sealing threaded pipe connections efficiently and reliably.

Approvals

NSF P1 Reg. No. 123001 
DVGW Approval (EN 751-1): NG-5146CQ0312

Applications

Ideal for sealing and locking metal pipe threads and fittings in plumbing, heating, gas, compressed air and industrial pipework systems where a durable, vibration-resistant and leak-free connection is required.

We offer nationwide next working day delivery on stocked products for orders placed before 12:00 pm, subject to stock availability.

Delivery charges are calculated based on your order's size, weight and destination and will be shown at checkout where applicable.

Some oversized, bespoke or non-stock items may require additional lead time. If this affects your order, we'll let you know as soon as possible.

Collection is available from our warehouses in Rochdale, Halesowen and East Kilbride, subject to stock availability. Please check the individual product listing for collection availability.