Laying up the firebrick floor
After the pad cured it was time to lay the firebrick floor. This was bedded in fireclay mixed with a small amount of fine sand. If I was to do this part over I would not use the sand. It caused the fireclay to dry very quickly. Before troweling on the fireclay, thoroughly mist the surface of the concrete so that it does not wick all the moisture out of the fireclay. Work with small sections at a time.
Before I started bedding the firebrick I mocked up the oven chamber walls. I discovered that my first mockup did not leave enough room at the front of the oven for the doorway and chimney, so I moved the whole chamber back a few inches.
One thing I quickly discovered about working with fireclay; make sure you wet the concrete pad and dip the firebrick in a bucket of water. Otherwise the dry concrete and firebrick rapidly draws most of the moisture out of the fireclay, leaving it virtually unworkable. More tips on working and mixing fireclay in the next section.