Plastic refractories are firebricks in plastic putty-like form which can be installed by ramming the plastics with a wooden hammer or air rammer into any shapes required. After installation, it is baked with operation temperature of the furnace itself (over 1,000°C) to form the tough walls. Castables are refractory cements which are mixed with the proper amount of water for installation. May be poured into frames or trowelled as is the case with ordinary cement. After installation by whichever method, it hardens to a sufficient strength. From among various types of products, the most common products are listed below. THERVEK PX-BD - Other monolithic refractories High-strength joint packing and bond. A paste-type product consisting of refractory aggregate and water glass binder. Can be used to fill joints by inserting a tube into the open space between brick joints and filling them directly with the product. When performing patching repairs, a thin underlay coating of PX-BD can be applied to the surface of the base material using a trowel or similar tool. Doing so increases the adhesive strength of the bond between the base material and the patching material, increasing the effectiveness of the repair. When PX-BD is heated to temperatures in excess of 500°C, chemical bonding occurs, increasing the strength of the refractory (i.e. heat setting).