Thanks for the info and the time !
Kirt from Spokane WA
My Answers to cracks in Tandoor clay
On the second large Tandoor, my bottom inside pot has cracked, and several other people have had the same. To be honest this doesn't bother me as it doesn't affect the performance or cause any issues. Note this is the inside pot at the bottom, so is not visible. The outside bottom is in perfect condition, also the top inner pot where I cook the bread is not cracked. I should also point out I have two thin cracks in the bottom pot, but nothing is falling apart.
Someone on my video or blog was mentioning about the first two burns should be at a lower temperature to get all the water out of the clay pot. I am not saying that is true or not, but it goes against what someone else had told you. Another person has said about having a grid on the bottom to keep the charcoal off the pot itself.
There are lots of experts out there, but who knows if they are right. How do you know you don't have a faulty or cheap made pot? Look my view is life is too short, just do it and see what happens. I have been cooking in the latest oven since September, and it works as good today as it did then. Yes I have cracks in the bottom inner pot, but you only see them if you put your head in the oven. Say in September I am not happy with the cracked pot, I can always try repairing with clay, or just simply replace the inner pot. It is a quick and easy job to do, and I would have had a years cooking on a £4 pot. As I say life is too short to get bogged down in the details.
The one pot that does matter is the outer pot, as that is the one you see and holds everything together. Just make sure your insulation is good.
Now coming back to your other question regarding a grate on top, I haven't done that but other people have. Here is a link to John's Tandoor, which is a different design to mine, but he uses a grate.
He has a huge amount of success with this, and he is regularly sending me pictures of his meals cooked on it. Here is an example from his last meal, you have just got love John's presentation: