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Fire Magic Symposium 2001
shaping the roof with earth

1. Before the earth former for the dome can be built a support of timber is needed at the level of the wall. This gives a firm platform for building the earth form. The platform should be made of several small pieces so it will collapse easier.

2. The timber platform is supported by bricks and timber from underneath. When the dome has finally been cast and set hard, these supports can pushed out and the earth platform will collapse for removal leaving the dome in place on the kiln walls.

3. The platform is also supported by pieces of timber where necessary.

4. The timber platform has been covered with sheets of cardboard and the edges are sealed with clay to prevent the earth falling thorough into the kiln chamber.

5. With the platform completed the earth can be piled on top.

6. The earth is formed into the required dome shape. The shape can be adjusted to suit the arch heights and the centre height of the dome.

7. The shape of the dome is important for the visual aesthetic of the kiln as well as for the function of the kiln. The final shaping compacts the earth into a solid mass.

8. Once the earth form is finished then a layer of clean, fine sand is put over the soil. This makes can be refined into a smooth shape for casting over.

9. The sand form is trowelled over the earth former. The sand must be kept damp and is continually sprayed with water so it sticks together better.

10. Tamping down the sand and adjusting the final shape.

11. The sand form is completed.

12. The completed form is covered with plastic sheeting. This will prevent the sand from sticking to the refractory cement and to make easy removal of the form after the cement has set.