Here are the ingredients: Clay, Straw, and Sand.

The hay needs to be finely chopped.

A mixture of 3 parts sand to 1 part clay is moistened with water.

Then the fun begins!

With feet, you try to get all the lumps out of the clay.

Here's a good method for mixing everything. Just lift the tarp, and roll it up like a burrito. It's good for mixing in the straw, too.

Next, the straw is worked in.

When all is well-mixed, the cob is formed into loaves. These are a bit small for a building, but fine for an oven.

As the oven is already partially built and has dried, we mix slip (a thin clay-water mixture) to glue this layer to the previous one.

The slip is applied over the existing dry layer.

Now, it's time for cob. The first loaves are placed on the shelf of the supporting foundation.

Successive loaves are locked into the previous loaves by pushing a thumb through the new loaf into the underneath one, thus weaving them together with straw.

The last layer of cob can be smoothed. It can also be formed into decorative shapes, perhaps representing natural beings or objects.

This is a view of the interior. It has some firebricks as the floor. On top of that was built a mound of wet sand. The oven was built on top of the sand. When the oven was dry and structurally sound, the now-dry sand was scooped out. This type of oven could have been built in one session by several people, or in several sessions over months, as this one was.

Here are the happy cobbers.

The pictures that follow are all from that cobbing session.