The first time a tandoor is used, the temperature must be gradually increased to condition the interior of the oven. This step is crucial in ensuring the longevity of the tandoor. Its easily can be done by:

✔️ starting a very small fire

✔️ slowly adding fuel to gradually increase the amount of heat inside the tandoor.

Also we would like to point out that the hairline cracks might form during conditioning. This is absolutely normal and will not affect with the performance of the tandoor oven. When the oven cools off, the hairline cracks will barely be noticeable. They are essential in allowing the clay body of the tandoor to breathe. The slower the temperature inside the tandoor is increased during its first use, the fewer hairline cracks will appear.