Flexible Silicone to Extreme-Heat Fire Cement

Soudal high heat resistant sealants cover applications where ordinary sealants may be exposed to more heat than they are intended to handle. But temperature alone doesn't decide the product. A flexible joint around heating equipment has different demands from a rigid gap around a fireplace, oven or furnace.

Industrial Shed's range brings together Silirub HT-A, Silirub HT-N & Firecement HT. Silirub HT-A & HT-N are high temperature silicone sealants that retain elasticity after curing. Firecement HT takes another approach, forming a hard seal for suitable extreme-temperature applications.

For maintenance crews, mechanical trades & installers, the practical decision comes down to three things: how hot the area becomes, what the sealant must adhere to & whether the joint needs to move.

For general sealing jobs away from high-temperature zones, browse Adhesives & Tapes.

What Are Soudal High Heat Resistant Sealants?

High heat resistant sealants are formulated for joints, gaps & interfaces exposed to elevated service temperatures.

Within this Soudal collection, two different technologies cover very different requirements.

Silirub HT-A is an acetic-cure silicone with temperature resistance up to 285°C. It remains permanently elastic after curing & is intended for compatible high-temperature sealing applications.

Silirub HT-N is a neutral-cure, high-modulus silicone rated up to 280°C. It also retains elasticity after curing while offering a different curing system from HT-A.

Then there is Firecement HT.

Rather than behaving like silicone, Firecement HT cures into a hard joint. Its temperature resistance reaches up to 1500°C, making it relevant to suitable extreme-heat applications around stoves, ovens, fireplaces & similar installations.

The important distinction is simple: Silirub HT products flex. Firecement HT sets hard.

That difference can matter more than choosing whichever cartridge carries the largest temperature figure.

Where surrounding masonry or concrete needs attention before sealing, explore Concrete Repair & Restoration.

Why Choose Soudal High Heat Resistant Sealants?

Three products create three distinct selection paths rather than forcing one formulation across every heat-exposed job.

► Up to 285°C with Silirub HT-A – elastic acetic-cure silicone for compatible high-temperature applications
► Up to 280°C with Silirub HT-N – elastic neutral-cure silicone where its curing system better suits the application
► Up to 1500°C with Firecement HT – hard-setting material for suitable extreme-temperature joints & openings
► Elastic sealing options – Silirub HT-A & HT-N retain flexibility after curing
► Rigid sealing option – Firecement HT creates a hard joint where flexibility isn't required
► Mechanical applications – selected Silirub products suit specified sealing around pumps & engines
► Heating applications – flexible high-temperature silicone options are available for suitable heating installations
► Extreme-heat applications – Firecement HT covers suitable ovens, stoves, fireplaces & other very high-temperature areas

Before resealing an existing installation, old material may need careful removal. Cutting Tools can assist with appropriate preparation work.

Common Applications

Two joints can sit on the same piece of equipment & still require different sealing products.

The useful comparison isn't simply hot versus cold. Consider heat, movement & material together.

Heating Equipment

Repeated heating & cooling can introduce expansion & contraction around an installation.

Where the joint needs an elastic seal, Silirub HT-A or HT-N may suit compatible heating applications within the specified conditions of the selected product.

Pumps & Engines

Heat isn't the only factor around mechanical equipment.

Pumps & engines can introduce vibration plus thermal changes. Soudal identifies suitable pump & engine sealing among the applications for Silirub HT-A & HT-N, making cured elasticity particularly relevant.

Stoves & Fireplaces

A stationary gap around a stove or fireplace can require a completely different material response.

Firecement HT is designed for suitable extreme-heat joints & openings. Once cured, it forms a hard seal rather than the elastic joint created by silicone.

Ovens & Furnaces

Very high operating temperatures can quickly move an application beyond ordinary silicone territory.

Firecement HT provides temperature resistance up to 1500°C for suitable installations. Its rigid cured state still needs to match the way the joint is expected to behave.

Heat-Exposed Pipe Connections

Temperature changes can cause pipework & surrounding components to expand or contract.

If movement needs to be accommodated, the permanently elastic characteristics of Silirub HT-A or HT-N may be relevant, subject to the substrate & operating conditions.

Workshop & Plant Maintenance

Maintenance work rarely arrives labelled with the exact sealant required.

Technicians may encounter machinery housings, heating equipment, pipework, pumps or previously sealed joints. Identifying what failed, what temperatures are present & whether movement occurs provides a better starting point than copying the product that happened to be there before.

For surrounding maintenance & adjustment tasks, browse Hand Tools.

Product Selection Guide

Use this sequence before choosing a cartridge:

Establish the service temperature.
Decide whether the cured joint must move.
Identify the substrate.
Choose the appropriate curing system.

Soudal Silirub HT-A

Silirub HT-A suits compatible applications requiring a flexible acetic-cure high temperature silicone.

Key characteristics include:

► Temperature resistance up to 285°C
► Acetic curing system
► Permanently elastic after curing
► Excellent adhesion on metals, glass & glazed substrates
► Suitable for specified heating installations
► Suitable for specified pump & engine sealing
► Black finish

HT-A can be useful where elevated temperature & joint flexibility need to coexist on a compatible substrate.

Soudal Silirub HT-N

Silirub HT-N provides a neutral-cure alternative for suitable high-temperature sealing work.

Key characteristics include:

► Temperature resistance up to 280°C
► Neutral curing system
► High-modulus formulation
► Permanently elastic after curing
► High adhesion strength
► Suitable for specified heating installations
► Suitable for specified pump & engine sealing
► Black finish

The difference between HT-N & HT-A isn't a contest between 280°C & 285°C. Their curing chemistry & compatibility with the application are more useful distinctions.

Soudal Firecement HT

Firecement HT moves into a different class of application.

Key characteristics include:

► Temperature resistance up to 1500°C
► Hard-setting after curing
► Ready-to-use formulation
► Asbestos free
► Intended for suitable high-temperature joints & openings
► Suitable for specified stove, oven & fireplace applications
► Black finish

Its extreme temperature capability is valuable where required, but the cured joint does not provide the flexibility of Silirub silicone.

Which One Fits the Job?

Expert Tips

Don't Buy the Biggest Temperature Number

Seeing 1500°C beside 280°C can make Firecement HT appear to be the automatic upgrade.

It isn't.

The products cure differently. If the joint needs elasticity, the higher temperature capability of a rigid product doesn't solve the movement requirement.

Watch What Happens When the Equipment Cools

Installation temperature tells only part of the story.

Think through a complete operating cycle. Materials can expand while equipment heats & contract as it cools. That repeated change can influence whether the finished joint needs flexibility.

Treat HT-A & HT-N as Different Products

Their names are similar. Their chemistry isn't identical.

Silirub HT-A uses an acetic curing system while HT-N is neutral cure. Check the actual surface being sealed before deciding which formulation belongs there.

Investigate the Old Seal Before Removing It

A failed seal can tell you something.

Cracking may indicate movement. Loss of adhesion can point towards contamination, preparation or substrate compatibility. Heat damage may suggest the previous product wasn't appropriate for the operating conditions.

Understanding the failure can help avoid recreating it.

Measure Heat Where the Sealant Lives

A furnace may operate at one temperature while an external joint experiences another.

Product selection should consider the conditions at the sealing location rather than relying only on the headline operating temperature of the equipment.

Give the New Product a Sound Surface

Heat-resistant material still needs proper preparation.

Loose residue, deteriorated sealant, grease, dust & contamination can compromise the new application. Prepare the area according to the requirements of the selected product rather than covering the old joint with another layer.

Separate High Heat From Fire-Rated Construction

These terms describe different requirements.

A sealant's temperature resistance does not by itself establish that an assembly meets a particular fire-resistance requirement. Where the work forms part of a specified fire-rated construction system, follow the requirements of that system.

Before handling sealants or preparation products, How to Read a Safety Data Sheet - A Quick Guide for Workshop Operators is a useful reference for understanding supplied safety information.

Select appropriate Hand & Arm Protection around the product, preparation method & working conditions.