According to The Refractories Institute, “refractories are heat-resistant materials that constitute the linings for high-temperature furnaces and reactors and other processing units”. But, in addition to being resistant to thermal stress and other physical phenomena induced by heat, refractories also withstand physical wear and corrosion by chemical agents. So, if you want to build structures that are subject to high temperatures, ranging from simple to sophisticated ones, e.g. fireplace brick linings to reentry heat shields for the space shuttle, you definitely need to use this amazing material.
On the other hand, heat resistant plaster is a replacement material for gypsum plaster and it is recommended when the temperatures are too high for gypsum plaster to stay on the wall. Heat resistant plaster is a fully blended fine powdered material which is mixed with water to achieve a floating consistency. Heat resistant plaster should be used on walls and chimney breasts where the temperature is likely to exceed 50°C particularly around the so-called “hole in the wall” type fires and stoves.
If you are planning on building a fireplace, chimney or, maybe, even an outdoor pizza oven, both refractories and heat resistant plaster will make it much safer and you can easily avoid getting your hands burnt.
Any material can be described as ‘refractory’, if it can withstand the action of abrasive or corrosive solids, liquids or gases at high temperatures. The various combinations of operating conditions where refractories are used, make it necessary to manufacture a range of refractory materials with different properties. Refractory materials are =available in varying combinations and shapes and they are suitable for different applications.
But how does this work? Refractory materials consist of high melting particles bonded together. At high temperature, glass fuses and as the temperature rises, the resulting slag increases in quantity. . The temperature at which this action results in the failure of a test pyramid (cone) to support its own weight is called, for convenience, the melting point of the refractory.
Firebrick is the most common form of refractory material. It is used extensively in the iron and steel industry, nonferrous metallurgy, glass industry, pottery kilns, cement industry, just to name a few. Firebrick linings shield the metal walls of the stove from intense hot spots. As the firebricks heat, the warmth of the fire radiates evenly through the outer casing of the stove.
Stoves lined with firebrick store more heat than plain metal stoves and radiate heat longer than all-metal constructions. Stoves with firebrick liners also can withstand hotter fires than metal stoves and burn fuel more efficiently than a stove with hot and cold spots. After many cycles of heating and cooling, firebrick cracks, but cracked bricks that stay in place work as well as intact bricks. When part of the brick crumbles, the brick needs to be replaced . Rebuilding a firebox can require refractory mortar as well.
If you want to safely use refractories for your home, you need the opinion of some experts first. But, keep in mind that when it comes to your do it yourself endeavors that involve things like heat resistant plaster it might be better to let the professionals handle it.