Using an epoxy paste to rebuild and repair a worn pipe

The rebuild of a sulphuric acid pipline worn by corrosion and chemical attack and rebuilt by epoxy paste
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Time waits for no man. And it waits for no pipe either. Lines can degrade and become worn and when this happens, it becomes necessary to carry out a pipe rebuild.

Yes, you read that right. Not replacement. Not repair. Rebuild. The outside of pipelines can undergo refurbishment and reinforcement by building a new shell around the weakened section using an epoxy paste.

Whether corrosion has eaten away to cause damage, chemicals have attacked the interior of the line as they pass through or you just happen to have a pipe which is 90-years-old, here is how to rebuild with epoxy paste.

What is an epoxy paste?

An epoxy paste is made of two components, resin and hardener. When these are mixed together, a chemical reaction takes place which causes the soft paste to set into a rock hard material as strong as steel.

Epoxy pastes can come with different formulations depending on the pipe type or surface to be rebuilt. Metal-filled pastes seamlessly repair metalwork at the same time as offering high corrosion resistance, for example.

Ceramic-filled epoxy paste meanwhile set to a harder-wearing, ultra-smooth finish. This is useful for rebuilding damaged machinery, as well as protecting parts subjected to extreme wear and tear in abrasive environments.

Pastes can also be specially formulated for high-temperature applications. A titanium-filled epoxy will offer resistance up to 250°C and greater compressive strength for use on steam pipes.

How to use an epoxy paste to rebuild a worn pipe

A metal-filled epoxy paste like Industrial Metal is ideal for the rebuild and repair of pipes. It bonds easily with all types of metal and most plastics and even cures on wet surfaces.

Prior to the application, the pipe undergoing repair requires some preparation. The surface should be free of paint, rust and grime to approve adhesion.

The resin and the hardener are mixed in equal ratios using a spatula. The paste is then spread over the worn section of pipe using a putty knife.

Pushing the paste firmly onto the pipe surface ensures maximum contact and avoids trapping air between the paste and the surface.

A 60 minute work time enables careful application without the threat of premature curing. It can be applied as thick as is required and will set to create a new metal surface.

Not only does this new surface protect against external wear, but the casing encompassing the pipe keeps fluid in should the pipe be breached internally.

A full cure is achieved in 24 hours, after which you have effectively created a new pipe over an old pipe.

Where can epoxy pastes be used?

Epoxy pastes can be used to repair virtually any pipe that requires strengthening. It is most frequently deployed in industries where pipelines are subject to attack from chemicals and corrosion, hastening the weakening process.

Take this sulphuric acid pipe rebuild at a petrochemical plant in Saudi Arabia for example. An elbow was discovered to have degraded from 22mm thickness to just 1mm.

Industrial Metal was hastily used to rebuild the line, adding 22mm of thickness to return the pipe to specification.

This meant that when the sulphuric acid eventually ate away at the 1mm of original pipe remaining, it would still be contained by the new metal shell encompassing the elbow.

Without the epoxy paste rebuild, the worn pipe would have needed to be taken out of service and replaced in the best case scenario.

In the worst case scenario, the pipe could have been breached and sulphuric acid able to escape at the 22 bar pressure the line operated under. A scary thought.

Products that work alongside epoxy paste

A composite pipe repair bandage can be used in conjunction with epoxy paste for added strength and further reinforcement of the line.

Once dipped in water, a composite repair bandage begins to set rock hard in minutes. It is wrapped and smoothed around the pipe and over the paste whilst the epoxy remains a little tacky.

Within minutes, the bandage will cure to form another outer layer of protection. When combined with a WRAS approved bandage such as SylWrap HD, Industrial Metal has passed independent BS 6920 standard testing.

This means it is certified to British standards as safe to use with drinking water – an important consideration if the pipe undergoing rebuild is a water supply pipe.

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