M3Cast

Collar based metal seals for pipes, joints and flanges

M3Cast uses custom mould collars filled with low melting point alloy to seal leaks around pipework, valves and flanges. The collars are designed around real equipment, applied with minimal disturbance and create reversible metal seals that keep critical assets online.

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The Challenge

Leaks at joints and flanges on processes that are hard to shut down

Many of the most troublesome leaks occur at joints, flanges and manifolds, exactly where access is restricted and shutdowns are expensive. Traditional repairs often require draining or depressurising systems, mechanical rework and full recommissioning. On live assets that can mean lengthy outages and significant risk.

M3Cast was developed for these situations, where you know where the leak is, but taking the asset out of service would be disruptive or impractical.

Overview

A custom mould that becomes a metal seal

M3Cast combines a reusable mould with low melting point alloy. The mould is clamped around the leak location and filled with alloy which flows into gaps and leak paths. As the alloy cools it solidifies, the mould is removed and reused and the alloy seal remains in place stemming the leak.

Mould geometry designed for your asset
Seal against flowing gaseous leaks of 10 bar
Low temperature, deployed at <150°C
Fully reversible

Applications

From SF6 equipment to industrial plant

Electricity transmission

Mitigating leaks on small bore pipework and fittings associated with SF6 insulated equipment.

Nuclear decommissioning

Accessing confined or shielded areas where traditional leak sealing is challenging.

Industrial process assets

Cracks, pinholes and defects in vessels, housings and structures that are difficult to isolate.

Proven Performance

We back every claim with data, test evidence and clear assumptions.

Up to 98%

Average reduction in simulated SF6 leak rate in National Grid testing at 7 bar.
0 cure time

Metal seals work as soon as the alloy solidifies.
Up to 15 bar

Demonstrated pressure tolerance for selected M3 applications, subject to engineering review.
Reversible

Alloys can be reheated and removed when equipment is replaced.

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Reversibility

Metal seals that do not close off future options

M3Cast creates a solid metal seal, but it is not a permanent modification. The alloy can be reheated and removed, so equipment can still be inspected, overhauled or replaced later. You get rapid leak recovery now and the freedom to make longer term decisions on your own timetable.

Alloy can be reheated and safely removed
Original component can be accessed and inspected
Supports long term replacement and decommissioning plans

Frequently Asked Questions

Straight answers to common questions about M3Cast and how we work with your team.

What types of leaks can M3Cast be used on?

M3 is designed for gaseous leaks and low-rate liquid leaks, making it ideal for industrial and utility applications where conventional repair methods may be too slow or disruptive.
Is M3Cast compatible with multiple materials?

Yes. M3Cast can seal leaks across a range of materials, meaning you don’t need to worry about material compatibility when dealing with mixed metal or composite systems. This makes it flexible for diverse industrial installations.
Can M3Cast be applied while the leak is still flowing?

Yes, for gaseous leaks, M3Cast can be deployed whilst the system is live. This allows repairs to be carried out without shutting down operations, which saves time and avoids costly downtime.
What is the maximum pressure M3Cast can seal while the leak is flowing?

Currently, M3 Cast can safely seal leaks under pressures up to 10 bar but we haven't reached the operational limit. Get in touch if you have requirements for us to extend this capability for even higher pressure systems.
Is the M3Cast process ATEX rated?

Not yet. However, if ATEX certification is a requirement for your site, please get in touch with our team to discuss options and potential solutions.
How long does M3Cast seal last?

Our accelerated ageing tests show tens of years of durability, and real-world deployments have lasted 4 years and counting. M3Cast provides a long term solution for industrial leak management.

Case studies

Proof in Practice

M3 technologies have been trialled and deployed with leading utilities, moving from innovation projects into live operations.

Case studies from National Grid, and industrial clients show how M3 reduces leaks, avoids outages and supports net zero goals.

View case studies

Industrial

Technical Underpinning of M3 Alloy Sealing for Nuclear Applications

High hazard industries require a considered approach, underpinned by data.

Electrical

Development and Field Demonstration of M3 Technology for Transformer Oil Leak Sealing

National Grid Electricity Transmission (NGET) asked RW to investigate engineered solutions for sealing transformer oil leaks—an issue faced globally across transmission and distribution networks.