Clay
After many years building using lots of different clays, I use an amazing clay called Ashraf Hanna Clay - named after an Egyptian born potter who lives in Wales.
The clay is a lovely white colour, which makes a great background for any colours. Contained within the clay is a fine grog (a ground up fired clay powder), which adds strength to the pots when hand building. It also provides the pots with the ability to withstand the thermal shock during smoke firings.