Overview
Loctite 580 is a one-part, smooth, creamy thread sealant paste designed for locking and sealing metal threaded pipe connections and fittings. It’s based on a methacrylate acrylic system and cures anaerobically (in the absence of air) between metal threads to form a durable, pressure-resistant polymer seal.
The sealant is:
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Off-white, very high viscosity and non-running, so it stays where you apply it, even on larger threads and vertical joints.
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Medium strength, providing reliable sealing while still allowing disassembly with tools.
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Low halogen and low sulfur, making it suitable for power generation and other sensitive installations.
It is formulated to impart lubricity, give instant low-pressure sealing on assembly, and then cure to a solid, securing the thread against vibration and thermal cycling.
Typical service temperature range: -65 °F to +300 °F (-54 °C to +150 °C).
Key Features & Benefits
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Medium-strength, high-viscosity paste
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Very high viscosity (~600,000 cP) helps it stay in the thread roots and reduces run-off on vertical or overhead joints.
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Instant low-pressure sealing
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Provides a low-pressure seal immediately after assembly, then develops full performance after cure, reducing leak risk at start-up.
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Locks and seals metal threads
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Prevents loosening and leakage from shock and vibration in pipework and fittings.
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Cures on stainless and other “inactive” metals without activator
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Specially formulated to cure without heat or separate activators even on stainless steel and other low-reactivity metals.
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Low halogen / low sulfur
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Suitable for use in fossil fuel, solar and hydro power plant piping systems and other environments where contamination must be tightly controlled.
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One-part, no-mix product
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Ready to use straight from the tube; no mixing or dosing errors.
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Typical Applications
Loctite 580 is recommended for sealing thread fittings in industrial and power generation piping systems, including:
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Power plants
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Fossil fuel, solar and hydro power plant piping
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Instrumentation lines
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Water and coolant systems
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Fuel oil piping
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Low-pressure steam lines
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General plant and utilities
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Pumps and valves
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Hydraulics and compressors
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Condensers and gas lines
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Controls and electrical conduit
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Rad-waste and process support systems
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Use only on metal threads (tapered or parallel) where a reliable, serviceable seal is required.
How to Use Loctite 580
Always follow the latest Henkel Technical Data Sheet and your site procedures. The steps below are a general guide.
Step 1 – Preparation
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Disassemble the joint and remove any tape, old sealant and loose debris.
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Clean male and female threads so they are dry, oil-free and free of cutting fluids. Use a suitable solvent cleaner if necessary.
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Inspect threads; repair or replace badly damaged components.
Step 2 – Application
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Cut the tube nozzle to the desired bead size.
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Apply a continuous bead of Loctite 580 to the male thread, covering 360° around several pitches and working product into the thread roots.
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For larger diameters, ensure sufficient coverage to fill the clearance between threads, but avoid excessive globbing or over-application.
Step 3 – Assembly
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Assemble parts and tighten to the specified torque.
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Loctite 580 provides immediate low-pressure sealing; for higher pressures or aggressive media, allow cure per TDS.
Step 4 – Cure & Return to Service
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Typical full cure time is around 24 hours at room temperature on steel; passive metals and low temperatures may extend cure time.
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Only subject the joint to maximum system pressure and temperature after adequate cure.
Step 5 – Disassembly
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Use normal hand tools to disassemble; medium strength allows fittings to be serviced without destroying the threads.
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Remove cured residue mechanically (wire brush/scraper) and clean threads before reapplying fresh sealant.
Safety & Handling
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Avoid skin and eye contact with uncured material; may cause irritation or sensitisation.
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Use in a well-ventilated area; avoid breathing vapours.
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Wear appropriate PPE (safety glasses, chemical-resistant gloves, and protective clothing as needed).
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Do not allow uncured product to enter drains or natural waterways; dispose of waste in line with local regulations.
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Store in the original, tightly closed container in a cool, dry place within the temperature range recommended on the label/TDS.
Always consult the current Safety Data Sheet (SDS) before large-scale or routine use.
FAQs
Q1: What is Loctite 580 mainly used for?
It is mainly used to lock and seal metal threaded pipe connections and fittings, especially in power plant and industrial piping systems where low halogen/low sulfur products are preferred.
Q2: How is Loctite 580 different from PTFE tape or dope?
Unlike PTFE tape, Loctite 580 does not shred or create loose fragments that can block valves or filters. It also locks the threads against vibration, while providing lubricity during assembly.
Q3: Can Loctite 580 be used on stainless steel threads?
Yes. It is specifically formulated to cure without heat or separate activators on stainless steel and other “inactive” metals, making it suitable for a wide range of alloy fittings.
Q4: Is Loctite 580 suitable for plastic threads?
No. Loctite 580 is an anaerobic sealant for metal threads only. On plastics it may not cure correctly and could damage sensitive polymers.
Q5: What is the temperature range for Loctite 580?
The typical operating window is -65 °F to +300 °F (-54 °C to +150 °C), which covers most general industrial and utility services.
Q6: Do I need an activator with Loctite 580?
In most cases, no activator is required, even on stainless steel or other low-reactivity metals. An activator may be used if you need to speed up cure in low-temperature or borderline conditions.
Q7: Can fittings sealed with Loctite 580 be disassembled?
Yes. Loctite 580 is medium strength, so joints can normally be opened with standard hand tools, even after long service, while still providing robust sealing performance in operation.
