Fire Clay

What is fire clay and where to get it in nature?

All refractory are based on fire clay, what it contains, alumina and silica. In fact all high heat resistant firebricks are made of fire clay. Like heat resistant mortars, insulation, pottery, ceramics, ceramic blankets or ceramic tiles on space shuttle, origins of these start from the fire clay, its melting starts at 1600 Celsius °C or 2912 Fahrenheit °F point. Only special manufacturing technologies of those expensive materials change their properties and usage applications.

Fire clay is a normal mud, simple as that, but a mud with higher Alumina (AL) content. Has usually whiter-lighter color. Whitish to yellowish, pinkish, light brownish. It’s also cheap as mud. Refractory or pottery suppliers sell it. Even if it comes in dry powdered form in bags, fire clay is still very heavy .You only need one bag per dome if you buy the clay in dry powdered form. Commonly Alumina content of fire clay ranges between 24% – 34% Al and Silica from 50% to 60 percent .

In mass sense, even when in a dry powdered form with density of 1.303 gram/cm3 or correspondingly 0.753 ounce/cu-in, fire clay is still a heavy product; when compared with cement for instance.