A tandoor is a cylindrical clay oven that uses both convection and radiant heat from a charcoal or wood fire to cook a variety of Middle Eastern, Indian, Pakistani and Afghan foods. Similar to a masonry oven, the tandoor can reach heat in excess of 482 degrees C and is usually kept burning to maintain this constant temperature. The term "tandoori" is used when anything is cooked inside the tandoor, which is mainly used for assorted meats on skewers such as tandoori chicken and flatbread known as nan.
Pour a thick layer of vermiculite into the bottom of the dustbin.
Find the biggest terracotta pot that will fit comfortably inside the dustbin. Using a hand-held angle grinder with either the stonecutting or diamond wheel, cut the base off the pot. Save the base to be used as the tandoor lid, which keeps the heat from escaping.
Cut a piece of the rim out of the pot by first using a masonry bit to drill two holes under the section that will be removed to avoid cracking. Make three cuts, each at a 90-degree angle, creating a square hole that will serve as the air vent.
Cut the fire bricks, using a tile saw, to the necessary size so that they will fit into the base of the dustbin on top of the vermiculite, with as few gaps as possible. Adjust the height of the bricks so that the top of the pot will line up with the opening of the dustbin. Cut a hole in the dustbin at the same point where the air hole in the pot will line up on top of the bricks.
Set the terracotta pot into the cylinder, using great caution, and rotate until the two air holes line up. Seal any cracks or holes with fire clay to prevent heat from escaping.
Pour the remaining vermiculite into the area between the pot and the dustbin. To prevent the wind from blowing away the vermiculite or it sticking to foods as you cook, use bricklayer's mortar to cover the gap. Apply the wet mortar with a trowel all the way around the edge of the pot until a seal is formed. Once dry, add charcoal to the top of the fire brick and light to begin cooking.
Use extreme caution in operating saws and grinders. Do not allow children around the finished structure and avoid loose clothing that might catch fire, because the cylinder and liner will be around 482 degrees Celsius.