Prepare the base of the oven. Lay a wood pallet on a even surface where you would like to have your oven. Place the red bricks onto the pallet until they cover the entire surface.
Create a dome-shaped mound of sand to act as the support structure. Moisten the sand with water to create a mound as large as you would like the interior of the oven to be.
Cover the mound of sand with moist newspapers until it is completely covered.
Gently cover the mound with clay. Work from the base upwards to the pinnacle of the dome. Smooth the clay surface with your hands and watch for any cracks.
Allow the clay to dry for two or three full days.
Take a knife (a simple utility knife will do) and cut an opening for the oven which is 63 percent of the way up the dome. It is important that the opening is this high up the dome to ensure proper airflow and heating of the oven. Make the opening in the shape of an arch.
Remove the clay pieces you cut for the opening. Then remove all of the sand within the dome. If you can't reach all of the inside of the dome, you can use a shop vacuum to clear out the sand.
Look carefully for cracks on the dome's exterior and fill them in with clay. Smooth the clay into the crack so the surface is even.
Allow the oven to dry completely for three full days.