Soudal Silirub HT-N High Temperature Silicone Sealant 310ml

Soudal Silirub HT-N is a high temperature silicone sealant designed for jobs where standard silicone would simply give up and go home. Rated to 280°C in continuous service and up to 300°C for short-term exposure, it handles the kind of heat found in oven doors, boiler flues, heating installations, and industrial equipment without losing its bond or becoming brittle. It comes in a standard 310ml cartridge, so any gun will do.

It cures as a single-part product, which means no mixing, no mess, and no waiting around for someone to weigh out Part B. Neutral cure chemistry makes it safe to use against metals, glass, and most plastics without the corrosion risk you get from acetoxy (acid-cure) silicones. If you’ve ever had a standard sealant weep acetic acid onto a metal component and cause staining or pitting, you’ll appreciate why neutral cure matters here.

Once fully cured, Silirub HT-N remains permanently elastic. It won’t crack or crumble under thermal cycling, which is the real test for anything sitting near a heat source. Oven doors expand and contract every time they warm up and cool down, and a sealant that goes hard and brittle over time simply won’t last. This one moves with the joint.

Where High Temperature Silicone Sealant Gets Used

In domestic settings, this is the go-to product for repairing or replacing the glass seal on oven and range cooker doors. The seal on oven door glass takes a lot of punishment, and when it fails, heat escapes, glass becomes unstable, and efficiency drops. Silirub HT-N is formulated specifically to handle that environment. In white, it also blends well with most domestic appliances.

Beyond the kitchen, this sealant is widely used on heating installations, including sealing around boiler components, flue joints, pipe penetrations through heat-exposed areas, and connections between metals and plastics in high-temperature assemblies. Gaskets on pumps and motors, joints in industrial ovens, and anywhere else that sees sustained heat are all appropriate applications.

Bond Strength and Modulus

Silirub HT-N is classed as a high modulus silicone, meaning it’s stiffer than low-modulus variants once cured. This gives it better resistance to movement under load and a stronger overall bond, which is useful when the sealant is also doing a structural job, such as holding glass in place. For purely flexible expansion joints where movement is the primary concern, a low-modulus product would be more appropriate, but for bonding and sealing in high-heat assemblies, high modulus is generally the right call.

Storage is straightforward: keep it in the original container between 5°C and 30°C, and it has a shelf life of 12 months from manufacture. As with any cartridge sealant, if it’s been sitting on a cold van shelf all winter, bring it back to room temperature before you try to apply it. Cold silicone does not flow well and will give a poor finish.