8. (A) Red Clay Brick, Adobe Mortar and Refractory Mortar

1. Using a mallet and cold chisel split a number of bricks in half. These will be used for the small arch and the brick dome.  

2. Mark out with chalk the base structure (see fig.1) and put in place the supporting structures 

(see fig. 3) i.e. ply wood arches, paper mache dome). 

3. In a wheelbarrow mix adobe mortar: 70% clay soil, 20% sand, 10% cement. These are fairly loose percentages. You could use less soil (50%) and more sand and cement if you feel so inclined.

4. Place 1/2 bricks around the outside of the paper mache dome. The inside edges of the bricks need to touch each other (i.e. do not leave a gap between the bricks). Using you fingers, poke the adobe mix in between the bricks. Complete the full dome this way. 

5. In the same way make two arches around the ply wood structures using 1/2 bricks for the small arch and whole bricks for the larger outside arch. At the top of the larger arch leave a gap where you can sit the chimney.  

6. Place chicken wire around the chimney and use the refractory adobe (with higher ratios of cement and sand and a little gravel) to secure it in place. 

7. Remove the paper mache dome and ply wood supports. The structure should be able to hold itself. 

8. This layer needs to dry out for a couple of days. Be sure to keep it dry by covering it if it rains. You can light a small fire in the oven the next morning to help dry out the mortar completely.