Weicon HT 300 High Temperature Silicone is a one-part, room temperature vulcanising (RTV) silicone capable of long-term performance in high temperatures. This adhesive sealant is red in colour and bonds very well to a wide range of materials and surfaces.
HT 300 is an acetic cure silicone that exhibits very good elasticity after curing. It has a maximum elongation rating of 500% and also offers very good chemical resistance. HT 300 High Temperature Silicone also displays very good ageing and weathering resistance.
This silicone will adhere tell to most materials including steel, aluminium, glass, ceramics, silicone rubber and many forms of plastic and rubber. It has a pasty consistency as it comes out of the tube which makes for very accurate, deliberate application. It also possesses good dielectric properties.
HT 300 High Temperature Silicone will withstand ongoing exposure to temperatures between -60°C and +280°C as well as short-term spikes (of no more than 2 hours at a time) up to 300°C.
Weicon HT 300 High Temperature Silicone is available from Associated Gaskets in 85ml Squeeze Tubes and 310ml Cartridges. The squeeze tubes are designed for smaller jobs and allow you to apply this silicone by hand. The larger, 310ml tubes, fit standard size cartridge guns.
Guide to Use
Preparation of the Surface
The surface to which HT 300 will be applied must be clean and grease-free. Many surface contaminants (e.g. oil, dust and dirt) can be removed with Weicon Surface Cleaner. For heavily soiled surfaces we suggest Weicon Cleaner S Spray. Weicon Gasket Remover (formerly Sealant and Adhesive Remover) is suitable for removing old adhesives.
Most materials can be bonded well to themselves and among each other. For certain materials or extreme requirements, we suggest the use of an adhesion agent or primer. More information on these are available from Associated Gaskets. Alternatively, a mechanical surface pre-treatment (e.g. sanding or sand-blasting) can considerably improve adhesion.
HT 300 supplied in cartridge form and should be applied using a cartridge gun or automatic dosing system. Use of the 85ml squeeze tubes allows for cartridge gun free application.
Joining the Parts Being Bonded.
To ensure optimum wetting, the parts must be joined before the first skin has formed on the adhesive (skin-over time).
All Weicon elastic one part adhesives and sealants cure by reacting with humidity in the surrounding environment. The curing process starts at the surface of the adhesive and proceeds inwards from there. At 50% relative humidity and 23ºC, the cure speed is approximately 3mm in the first 24 hours.
Adhesive bonds of large surfaces and high layer thicknesses cure more slowly as the humidity cannot penetrate as quickly towards the inside of the adhesive if the outer layers have already cured. Higher temperature and/or higher humidity accelerates curing while lower temperatures and/or lower humidity slows it down.