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Description

Permabond A131 – KIWA & WRAS‑Approved Anaerobic Thread Sealant

Permabond A131 is a specialist anaerobic adhesive designed to seal threaded metal pipe connections carrying a wide variety of gases and liquids, including potable water. It forms an instant, durable pressure seal that does not dry out or shrink like traditional mastics, eliminating the need for frequent re‑tightening or rework.

The product is suitable for use on both parallel and tapered threads, and its delayed cure profile allows precise alignment and adjustment of components during assembly — a critical advantage in complex piping systems. Once cured, A131 provides a reliable, long‑term seal that resists vibration, thermal cycling, and chemical attack.

Permabond A131 is KIWA certified for use with hydrogen (Inorm KE214) and WRAS listed for contact with wholesome (potable) water, making it a trusted choice for critical systems including hydrogen pipelines, gas networks, hot and cold water services, and industrial process piping. It is also capable of resisting the thermal stresses generated when bonding dissimilar metals such as aluminium and copper alloys, where differential expansion could otherwise compromise the joint.

Supplied as a single‑component, room‑temperature curing adhesive, A131 requires no mixing or weighing. It cures anaerobically in close‑fitting metal joints (gap < 0.5 mm), forming a tough thermoset plastic that fills thread voids and creates a 100% metal‑to‑metal contact seal.

Key Benefits

• KIWA hydrogen certified – Approved to Inorm KE214 for use with hydrogen, gas, and hot water systems.

• WRAS listed for potable water – Suitable for sealing pipework and fittings in contact with wholesome (drinking) water.

• Excellent resistance to peel and impact – Toughened formulation provides reliable performance under vibration and thermal stress.

• Good adhesion to aluminium and copper alloys – Ideal for lightweight or thin components that may distort in service.

• Delayed cure for accurate alignment – Allows precise positioning of components before the adhesive sets.

• Instant pressure seal – Does not dry out like traditional mastics; rework is effectively eliminated.

• Removable with standard tools – Disassembly is straightforward for maintenance or modifications.

• Wide thread size range – Suitable for threads up to M56 (2″) and gap fill up to 0.5 mm.

Typical Applications

Permabond A131 is used across gas, hydrogen, water, and industrial process systems for:

• Sealing threaded metal pipework in hydrogen, gas, and water services

• Sealing parallel and tapered threads in valves, couplings, and fittings

• Bonding and retaining concentric copper/brass fittings and similar assemblies

• Sealing dissimilar metal joints (e.g. aluminium to copper, brass to steel) where thermal cycling occurs

• General industrial maintenance where a medium‑strength, pressure‑resistant anaerobic seal is required

How It Works

Permabond A131 cures anaerobically in the absence of air and in the presence of metal ions within close‑fitting joints (typical gap fill up to 0.5 mm). Once confined between metal surfaces, the adhesive gels and then cures to a tough, thermoset plastic that fills thread voids and creates a 100% metal‑to‑metal contact seal.

Typical cure development at 23 °C on M10 steel:

• Handling strength: 30–60 minutes (brass ~45–60 min; steel ~45–120 min depending on grade)

• Working strength: ~2 hours

• Full strength: ~24 hours

Cure speed is faster on active metals such as copper and brass, and slower on passive surfaces such as stainless steel or aluminium. Where required, cure time can be reduced further using Permabond activators (e.g. A905 / ASC10).

For potable water applications, recommended cure times before use typically include:

• Brass, copper, cast iron: 24 hours at ~21 °C

• Stainless steel, aluminium: 7 days at ~21 °C