loctite 561

Loctite 561

Product category:Thread sealants
Technologies:Acrylates, anaerobic cure
Agency approvals / certificates / specifications:NSF
Breakaway torque, Steel, M10:6.0 N·m
Color:White
Key characteristics:Disassembly: easy disassembly; General purpose
Operating temperature:-65.0 °F – 300.0 °F (-55.0 °C – 150.0 °C)
Physical form:Semi-solid stick

Overview

Loctite 561 is a semi-solid, anaerobic thread sealant stick designed for fine metal pipe threads and fittings. It comes in a convenient, non-drip stick that’s easy to carry in a toolbox and won’t spill or leak like liquids or pastes.

Once confined between metal threads and shielded from air, it cures anaerobically to create a reliable, pressure-resistant seal that doesn’t creep, shrink or block systems. Loctite 561 is a low-strength sealant, so joints can still be disassembled with normal tools.

It is NSF/ANSI 61 certified for contact with drinking water and operates typically from -65°F to 300°F (-55°C to 150°C).

Key Features & Benefits

  • Semi-solid stick – no spills
    Non-drip, semi-solid form in a self-feeding stick; ideal for field work and overhead applications.

  • Anaerobic curing thread sealant
    Methacrylate-based anaerobic technology cures between metal threads to form a durable polymer seal.

  • Instant low-pressure sealing
    Provides an instant low-pressure seal on assembly, then develops full performance after cure.

  • Low disassembly torque
    Low strength product designed for easy disassembly and maintenance without damaging fittings.

  • Clean system behavior
    Formulated so it doesn’t creep, shrink or break off to clog filters, valves or small passages.

  • UV fluorescent for inspection
    The cured material is fluorescent under UV light, enabling quick quality control checks.

  • Broad temperature range & NSF approval
    Service temperature -65°F to 300°F (-55°C to 150°C) and NSF/ANSI 61 certification support use in many industrial and water-contact systems.

Typical Applications

Loctite 561 is suitable for locking and sealing:

  • Metal tapered pipe threads and fittings up to approx. M80 / R3″ in size

  • Pre-torqued metal pipe joints that need reliable sealing without re-plumbing

  • Maintenance and repair work in:

    • Industrial plant piping

    • HVAC and compressed air systems

    • Process water and utility lines (where NSF-approved products are required)

Only use on metal threads; it’s not intended for plastics.

How to Use Loctite 561

Always follow the current Henkel Technical Data Sheet (TDS) and your plant procedures. Steps below are a practical guide.

  1. Surface preparation

    • Ensure metal threads are clean, dry and free of oil, tape and old sealant.

    • Wire brush or wipe if needed; heavy oils should be removed with a suitable cleaner.

  2. Application

    • Twist the stick to expose a small amount of product.

    • Rub Loctite 561 directly onto the male thread in a 360° band, covering several turns.

    • Apply more in the root of the threads, especially for tapered pipe threads.

  3. Assembly

    • Assemble the joint and tighten to the specified torque.

    • Loctite 561 gives an instant low-pressure seal; allow full cure time (typically 24–72 hours, depending on conditions) for maximum performance.

  4. Disassembly

    • Use normal hand tools to undo the fitting; low strength formulation helps avoid thread damage.

    • Clean off cured residue and reapply fresh product for reassembly.

Safety & Handling

  • Avoid skin and eye contact with uncured sealant; may cause irritation or sensitisation.

  • Use in a well-ventilated area and avoid breathing vapours or sanding dust from cured material.

  • Wear appropriate PPE: gloves, safety glasses, and protective clothing as required.

  • Do not allow uncured product to enter drains or natural waterways; dispose of waste per local regulations.

  • Store in a cool, dry place, tightly closed, within the recommended temperature range on the label.

Always consult the latest SDS and TDS for Loctite 561 for region-specific details.

FAQs

Q1: What is Loctite 561 mainly used for?
Loctite 561 is mainly used as a thread sealant for fine metal pipe threads and fittings, providing an instant low-pressure seal and reliable long-term sealing after cure.

Q2: Is Loctite 561 safe for use in drinking water systems?
Yes. It is NSF/ANSI 61 certified in the USA, which supports use in potable water systems when applied and cured correctly.

Q3: What is the operating temperature range?
The typical service range is -65°F to 300°F (-55°C to 150°C), suitable for many water, oil and general utility lines.

Q4: Can Loctite 561 be used on plastic threads?
No. Loctite 561 is designed for metal threads only. Anaerobic products may not cure properly on plastics and can stress-crack some polymers. Use a plastic-compatible sealant for those joints.

Q5: How strong is the seal—will I be able to take the joint apart?
Loctite 561 is a low-strength thread sealant, developed for easy disassembly with standard tools while still providing robust sealing performance in service.

Q6: Does it replace PTFE tape?
In many metal pipe applications, yes. Loctite 561 can replace PTFE tape and traditional paste sealants, offering cleaner application, no shredding, and reduced risk of pieces entering the system.

Q7: How long does it take to fully cure?
Full cure is typically reached within 24–72 hours, depending on material, temperature and thread size. It provides an instant low-pressure seal, but maximum pressure resistance is achieved after full cure.

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