Welcome to Granny Green's guide to Dubbo sustainability.
I look forward to exploring all things sustainable in the Dubbo region. From the urban backyard to innovations in agriculture, I will be engaging with those in our community who are out there making a difference. If you have a project you would like to share, drop me a line at firstname.lastname@example.org.
The latest project taking place in our back yard is a wood-fired earth oven.
The finished product will be a large, well-insulated dome built from clay, sand and straw.
At this point, we are still trying to perfect the base.
Ideally, your earth oven will be raised to a comfortable height for building and tending the fire, as well as manoeuvring pizzas, breads and roasts into and out of the oven.
Ours has come up a little short, with our salvaged bricks only stretching to build a round structure about half a metre off the ground.
Our mortar was a mix of clay and sand and we first spent a couple of weeks sourcing our materials, filtering the clay (dug from a friend's property) and experimenting to get the right mix. Our clay to sand ratio was about 1:2.
The best - and most entertaining, way to mix the materials is on a tarp with your bare feet.
Next, we took the opportunity to clear our yard of old chicken wire and scrap metal and our kitchen of broken pans and chipped crockery.
All of this “urbanite” went inside the base of the oven as filler.
Rocks or lumps of concrete would also work well here but you should avoid using wood or organic waste.
A few wheelbarrows of sand covered the urbanite to create a flat floor about 30cm from the top of the brick surrounds.
We then began laying in our insulation, in the form of dozens of empty wine bottles, donated by colleagues at the Daily Liberal.
These contributions raised quite a few questions, I can tell you, as they adorned my desk over the past weeks.
Despite the generosity of my workmates, the bottles came up short and our project will be on hold until the remaining bottles can be gathered. A mixture of sawdust and clay will then be packed around the bottles to complete the oven's insulation.
In the meantime I'd like to share some photos (scroll through the images above) from a reader in Lightning Ridge, Graeme Anderson, who has used glass bottles to build his pottery kiln, to terrific visual effect.
Graeme wrote, “I thought your readers and local craftspeople may be interested in this kiln firing. We used nearly 300 wine bottles, (not all emptied by me) mortared with a mix of clay and sandy soil. The necks of the bottles were exposed on the interior of the kiln, resulting in some very interesting shapes.”