Ground cork is put into a mold that is put into an autoclave (a big pressure cooker) and steam baked at a temperature of 300 degrees centigrade (572 degrees Fahrenheit), with no contact with air. The natural resins in the cork liquify and upon cooling, the mass solidifies. Afterwards, the blocks are cut to the desired dimensions.
Cork is also used in other ways. Duck decoy bodies are carved from corkboard. The special effects industry uses it in making movies. Regranulated cork was used in the movie “Ghostbusters” to imitate building debris raining down on people. It was used to look like volcanic rocks in the movie “Volcano” and “Dante’s Peak” When you see movie bullets impact something, it’s cork that comes flying up.