{"id":33,"date":"2015-02-08T03:23:53","date_gmt":"2015-02-08T03:23:53","guid":{"rendered":"http:\/\/appliedecology.com.au\/coboven\/?page_id=33"},"modified":"2016-01-03T04:30:49","modified_gmt":"2016-01-03T04:30:49","slug":"step-5-preparing-the-dome","status":"publish","type":"page","link":"https:\/\/appliedecology.com.au\/coboven\/how-to-build\/step-5-preparing-the-dome\/","title":{"rendered":"Step 5. Preparing the dome"},"content":{"rendered":"

To make a cob oven dome, you first need to prepare the wet sand mould that you put the cob over. \u00a0The basic principle is you create the sand mound, followed by a layer of wet newspaper, followed by packing your cob over it, building it up cob layer after layer, until it’s finished. \u00a0You can then cut a door, remove the sand – and bob’s your uncle – a cob oven is formed. \u00a0 That’s kind of it. \u00a0But lets start with the prep.<\/p>\n

Create the wet sand dome, damp newspaper and first layer of cob on the same day. \u00a0<\/strong><\/p>\n

We found sand at a local bush area, and filled up buckets of the stuff into our car boot. \u00a0We then brought it back to our oven site, popped it on a tarp, slightly wet it until it was like the type of wet sand you have when you build a sandcastle. \u00a0Then you just build your mould.<\/p>\n

The size and shape of your sand mould will be exactly the interior size of your oven of course. \u00a0 \u00a0<\/strong><\/em>\u00a0Remember big isn’t necessarily best – unless you have massive dinner parties every weekend, \u00a0we think smaller is more functional. \u00a0It’s likely to be used more often and is quicker to heat. \u00a0It will also hold the heat longer.<\/p>\n

The theory of the interior cob oven is that your first 10-20cm of your oven inside should be straight up, then shaped into a dome. \u00a0We kept it as best we could to the avocado shape that is recommended as the ideal shape for fire retention. \u00a0 The fire\/heat would ideally come up the\u00a0deep round part at the rear\u00a0then coming up the back wall and ceiling and then sloping down to the exit\/chimney or\u00a0door chamber.<\/p>\n

The circumference<\/em><\/strong> of your dome is determined in part by your floor. \u00a0Remember you will be building thick layers of cob which need to be supported by the base, so the dome is quite a lot smaller in circumference than your floor. \u00a0We used string – held in the middle by one person, while the end of it (with pencil or chalk, created a rough perfect circle to guide size. \u00a0 \u00a0Start packing wet sand. (remember, straight edges for about 20cm, then gentle avocado shape.)<\/p>\n

The height<\/em><\/strong> is important. \u00a0Try to get it about 75% the size of your width. \u00a0 \u00a0 Off you go – and build your sandcastle.<\/p>\n

You can see from our photos we didn’t quite get the avocado shape, and we didn’t quite get the straight up 10cm part. \u00a0Point being here it didn’t matter – so don’t be too hard on yourself!. \u00a0Our pizza’s now cook within 2 minutes of putting them in the oven. \u00a0So it’s working as it should.<\/p>\n

\n\n\n\t\t\n\t\t\t\t