Froschmarke refractory boiler putty is a potassium water glass based sealing putty. Guaranteed to be resistant to open flames and temperatures of up to above +1000 °C. Has good adhesion, is non-shrinking, completely seals off smoke and gas. For boilers, furnaces and stoves. With excellent adherence to metals and other materials, this product is used for sealing off flue-gases with simple application by trowel or spatula blade.