Instructions : Thanks to Nick Collins 🙂 . http://www.simplenick.com/tandoor-family-size.html . I think this is the best way to make a DIY Tandoor for many reasons.
Here is where to buy supplies for  DIY Tandoor using terracotta flower pots, if you are in Australia ( May also help if you are in New Zealand)
Top Pot x 1
Bunnings — Northcote 33cm Terracotta Italian Pot
https://www.bunnings.com.au/northcote-33cm-terracotta-italian-pot_p2855867
Bottom pot x 1
Bunnings — Northcote 27cm Terracotta Italian Pot
https://www.bunnings.com.au/northcote-pottery-27cm-standard-terracotta-pot_p2863559
Bottom ring x 1
Bunnings — Northcote Pottery 25cm Terracotta Italian Saucer
https://www.bunnings.com.au/northcote-pottery-25cm-terracotta-italian-saucer_p2855998
Outer pot x 1Â
Bunnings — Northcote Pottery 48cm Terracotta cottaSEAL Coin Pot
https://www.bunnings.com.au/northcote-pottery-48cm-terracotta-cottaseal-coin-pot_p2860411
Pot feet x 3 — To raise your tandoor above ground level
Bunnings — Northcote Pottery 9cm Terracotta Italian Pot Feet
https://www.bunnings.com.au/northcote-pottery-9cm-terracotta-italian-pot-feet_p2871932
VERMICULITE for Insulation x 1  — 40L Bag
Petbarn — https://www.petbarn.com.au/the-all-natural-vermiculite-pet-litter
Worried about safety? Â http://mommyperfect.com/2015/09/baking-with-terra-cotta-ceramic-pottery/
Is This Everything? 