Above the firepit we spread two sheets of plastic. This was to allow for movement of the furnace walls due to shrinking on drying. A bucket on its side would be the form for the stoke hole opening in the wall.

We started by building the inner wall first, taking care to keep it about 2” thick. We reused the plywood form from the IFoG Furnace for the ash hole, and to keep the angle of the wall correct we made a simple measuring device from some scrap wood.

In order to completely encase the ceramic fibre, every opening into the furnace had to be lined with a 2" thickness of daub which joined the inner wall to the outer wall. This can be seen at the stokehole and the ash hole, where we added flanges which became the starting points for the outer wall, and removed the bucket and the form. This allowed us to start on the tunnel, which we built in tandem with the inner wall.

When the inner wall reached gathering hole floor height we set it to the correct shape using a cardboard form and continued to work on the tunnel, building the outer wall and adding the layer of ceramic fibre. The trowel was used to keep the inside surface of the outer wall reasonably flat and to regulate the wall thickness.

We built the outer wall, again about 2” thick, adding the ceramic fibre as we went. Before we built it up too much we drilled the holes for the ceramic pot support bars and added the small rounded shelves for extra support on the inside of the furnace wall.