New Shoes

Not a lot happened today, I bought some new shoes.

Oven Build Part Three

As I did not have the energy to mix the the second layer of cob, on the same day as the first layer, I left the oven covered over with a wet dust sheet to prevent it from drying out to much before the second layer was applied.
The Second layer of cob was made the same way as the first just was a few hand fulls of straw added. I used garden shears to chop up the straw in to short lengths, roughly 5cm to about 15cm. Once the cob is all mixed, it is applied in the same fashion as the first layer again about 10cm wide, the only difference is the doorway...
As you can see, I left a gap in the second layer for the door to be cut out. It can be quite hard to create the arch over the top of the door, I made sure that it was all pressed firmly together, as it would be a major pain if the doorway collapsed. An important point is the height of the door, there is an ideal height for the opening which is around two thirds of the height of the dome inside, so two thirds of the sand pile in the middle, in the case of this oven it is around 30cm (as my sand pile was about 45cm).
At this part of my build I ran out of clay, so I had to dig up more, it came from a different area, and it produced a different colour and texture cob. but it went on okay and I was able to finish the second layer. (The colour difference can be seen is this picture)Earth ovens can be left link this, though unprotected will not last well in British weather. A "plaster" layer can be applied to make the oven look uniform, or have patterns shaped in to it. The plaster layer is the cob used on the second layer, but with shorter bits of straw, some people use manure and all manner of things, the layer is only about 2.5cm thick, much thinner than the previous layers. I choose to cover my oven in a lime render, I do not know if this was a good idea or not. I thought that lime, unlike cement, can change shape over time, it has some flexibility to it. I left the oven to dry for a few days before coating it in my lime render. I could not find a recipe for lime render, so had a bit of a guess, I think I used about 2 hydrated lime to 3 sand, I also put a very small amount of cement in to the mix to help it harden. Like cob plaster I only put a thin coating on. I left it to dry for a few days under a damp dust sheet, so that it would dry out too quickly.

Then it was time for the final stage, removing the sand. This is quite a rewarding moment. Cutting a hole (I recommend a large knife or similar) just big enough to pull handfuls of sand out (this is so you do not damage the entrance way while removing the sand). Once most of the sand is out the doorway can be made bigger or cut out totally.

And that is it one complete oven, it needs a while to dry out, after a few days a put a small fire inside this one, but it is still very damp, and we are heading in to winter now, so I need to build a shelter to keep the worst of the weather out. Once it is fully dry I shall try to cook something in it... and hopefully a guide to shelter building, not sure how it is going to look yet.
Things to come - Bellows (I hope to start on them soon) and a Shelter for my oven (hopefully before winter)

Oven Build Part Two

Right with the oven base done, the hard bits begin. To make the oven the right shape, a sand former must be built. First I drew the largest circle possible using a piece of chalk and string. I started to pile up sand in this circle, my aim was to get this sand pile to about 45cm high and shaped a bit like half an egg shell. In my first attempt I made the sand too wet so I would get my ovoid sand pile to about the right height and it would collapse under its own weight. I left it over night and started again the next day, and was able to create the desired height and shape.
Before continuing with the next stage, I placed a layer of news paper over the sand dome, wet so it would stick. This news paper comes in handy later.


The picture above is me starting the mix the Cob for the oven walls. The first layer of the oven is not proper cob, as it is only clay and sand (about one clay to two sand), the next layer will contain straw also. My clay came from the subsoil in the garden, it is mostly clay in my local area, so I was quite lucky I did not have to look far, the sand however came from a builders merchant. It is easiest to mix the cob with your feet, I do not think there is any other way to mix it really, but it is a lot of fun to get all messy. It is best to do the cob mixing on a tarpaulin or something similar, as it makes it easy to turn the cob over to make sure the clay and sand are thoroughly blended together. Once it looks well mixed, take a handful and make a ball, then squeeze 50 times (while keeping it a ball), then drop it from waist height, if it stays in shape, the mix is ready to use. If when dropped it cracks or falls apart, its is probably to dry, or not enough clay, if it flattens when dropped then it is probably to wet, either add a bit more sand, or leave it to dry out before using. I found that mixing all the cob for an oven is too much work for one person, I should have tried harder recruit to my friends. Taking handfuls of cob at a time, I built up the wall of the oven pressing downward on the cob, not on to the sand dome. The wall should be about 10cm wide, all the way around. Once I had covered the whole sand former with cob, I patted the new cob so it was smooth and ready for the next layer.

I shall continue tomorrow.

Oven Build Part One

Before I start to make the oven itself I looked around the internet on various websites, and borrowed a couple of books for information on pizza and bread ovens. (I shall put links at the bottom of this post.)
Original I had wanted to make a brick oven, but due to the temperatures reached inside such ovens, firebricks are required as others bricks would not be able to stand the heat and may crack or even explode. Firebricks are rather expensive so I had to look around for alternatives.
Fortunately for me, not far from where I live a land-share project were building an Earth oven, and looking for volunteers to help out. Having found earth ovens as an alternative to brick in me research I thought helping to make one, would make, building my own far easier. Much of my build was based on what I learned while helping at the land-share.

On with my construction, the picture in the top right is of the base I built for my oven to stand on, as I hope to use the oven more than once, having the oven raised off the ground will make it easier to use. I nailed together some bits of old planks to form a box, placed it where I wanted my oven to be, and leveled the ground around it so that my oven would also sit level. I filled the box with a layer of rocks and sand (about a third of the way up) then placed a plastic sheet down (to minimize moisture rising up from the ground) and then filled to the top of the box with earth, the box stands about 70cm high and 150cm by 100cm. Obviously you do not have to build a base, or you can make it out of other things, this was the best option for me, though it did mean I had to shift about a tonne of earth. I finished the box off with a light covering of sand ready for the next stage

The second step was putting down the base of the oven, the area where the fire is and the food is cooked. Again, ideally firebricks would be used for this, for the size of my oven, I would have needed about 30ish which was a lot more than I was willing to spend. Luckily my grandfather came across some blocks from old storage heaters, hopefully they will work. I also used 3 clay house bricks for the entrance to the oven.

In the picture to the left you can see that I bedded the clay bricks straight on to the sand, and the storage heater blocks, I bedded on a concrete of sorts to raise them to the height of the clay bricks. The concrete was a mixture of sand, Mendip dust (fine limestone chipping/dust from local quarries), cement and hydrated lime (the lime adds some heat resistance to the concrete)

The base when finished measured about 70cm by 70cm excluding the clay bricks. I brushed a dry mixture of hydrated lime and soft sand in the gaps between my blocks, I left my oven base to harden for a few days before I continued with the next stage.

Links:
"Build Your Own Earth Oven"(Book everyone recommends to people looking to build and earth oven(Amazon))
Greg's Earth Oven (One of the first sites I came across)

Traditional Oven.com (Lots of useful info about wood burning ovens, tips on cooking and other such things)

I did have more but I cannot find them right now, I will add more later.

Plymouth

Well I am off to Plymouth tonight, so I will have to start work on blogging on Saturday evening...

Coming soon...

I have just finished making an earth oven. It had been a long time in the planning, and the building process was drawn out by me waiting for things that did not happen, but now it is done I feel I want to share it with people. I also have other smaller projects in the works, which maybe of interest to people, but then it may not. Anyhow, in the next couple of days I will up load some pictures the building of my oven, and some finished photos, and then in the coming weeks I shall hopefully attempt cooking some pizza.

Other things I am currently planning, I am going to make some bellows, which should make building fires in the oven easier. Secondly I am looking into making a small charcoal kiln. Then there are a few small items want to make, so we shall see how it goes over the next few months, and see if I keep up with blogging about it.