New Earth oven build Melbourne

[MWP]

Hi,
I've planned and built the base for a wood fired earth oven using knowledge I've gained from this website.
Now I'm ready to build an Earth oven and am looking for a suitable supplier of clay in Melbourne, preferably the Western Suburbs.
The base has a 10cm vermiculite thermal layer above a 10cm reinforced concrete structural layer. Then it is capped with 8 fireclay tiles.
Inside diameter is a bit on the small side (600mm-700mm depending on how thick I make the dome).
I made a small test dome using clay from my small backyard, but won't have enough to make a full oven including the insulating layer.
Can anyone recommend a suitable clay supplier in Melbourne?
TIA.

[UtahBeehiver]

Re: New Earth oven build Melbourne

Check with David S (Aussie), he is a pottery/ceramics instructor.

[TropicalCoasting]

Re: New Earth oven build Melbourne

Try ringing an Art school
A friend is a potter in Melbourne he did his study at Pahran College..try there.
I remember he would go out to Smeaton a fair bit to dig his own too.
Western Suburbs is black clay with lots of volcanic rocks not really that great,outer eastern suburbs has some good clay soils if you know someone who needs some holes dug.

[david s]

Re: New Earth oven build Melbourne

You can dig for the stuff yourself. Just find a spot that has a reasonable clay layer below the topsoil. It does not need to be a processed potters clay, it can contain some soil and other impurities. The best way is to dig it out, allow it to dry and break it up into pieces no larger than a fist. Place the dry material onto a large sheet of plastic and begin wetting it down and mixing it with bare feet. This activity can be good fun if you combine beer and some assistance from young females. Periodically grab a corner of the plastic and fold the mix back into the middle. You can also add some powdered Bricklayers Clay, which is pretty cheap. Skip the idea of using potters clay, it is too expensive because you are paying for a highly processed product designed specifically for a different purpose that is not required for a clay oven.

[MWP]

Re: New Earth oven build Melbourne

Thanks for all your responses. I bit the bullet and bought 100kg of ball clay from Northcote pottery.
Hope to publish photos of the finished product.

[MWP]

Re: New Earth oven build Melbourne

Hi,
My insulation layer has developed cracks.
I've let the dome air dry and kept it covered from the sun for five days.
The weather has been dry with one day of 34C.
The cracks are about 4mm wide and go down to the thermal layer.
Material used was 2:1 sand/ball clay plus 100L vermiculite.
Should I be worried?

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[cobblerdave]

Re: New Earth oven build Melbourne

Gday

I recon a lot of small ones beat a big one hands down
A thin slurry of clay and sand pushed into the clay when it hot and they are at there largest. Dampen a handbroom in a bucket of water and rub the suface to smooth again.
You can't finish with Portland cement render or waterproof paint either the clay needs to breath. So its an old school lime/sand render or lime paints to finish. And overhead cover to protect from the wheather.
Regards dave

[david s]

Re: New Earth oven build Melbourne

dry the thing out slowly with plenty of small fires. Cover it if it looks like rain. Don't do your outer shell until you've had at least 10 decent cooking fires or you're likely to crack the outer shell. Throw some sheet plastic over whilst firing it to test if it is still purging itself of water.

[MWP]

Re: New Earth oven build Melbourne

Thanks for the advice. The cracks got to about 5mm, but have stopped growing and expanding. I've been keeping fires going at about 150 degrees for several times a day. There was no smoke coming out of the cracks, so that's a good sign.
I've put 20kg of hydrated lime + 30L water in a wheelie bin to "perculate" for a week or more. This will become the lime render.
I made a pizza peel from a pipe blanking plate and an old lacrosse stick:
Infernorama

[cobblerdave]

Re: New Earth oven build Melbourne

G'day
Just as important is to let the oven cool to ambient . This way the moisture that is deep in the oven has a chance to migrate back to the dry surface inside, capillary action will do that. The next gentle fire will remove that lot.
The worst thing that happens is you find a sudden jump in temps. Yep you beauty.. Pizza... And you go the max.
Worst result inside top of the dome dry and able to heat up , the rest full of water . Steam, uneven heat, cracks. Cracks that shouldnt be.
Old school oven , old school pace.
You should take as long to sand and finish a piece of furniture as it took to build they used to say.
You can still cook . Some pita bread on the hearth. Some chicken legs in a baking dish.
Regards dave

[Lancer]

Re: New Earth oven build Melbourne

Hear him. Slow's the word. :b: Warm, cool, warm..etc

[MWP]

Re: New Earth oven build Melbourne

I've done 10 slow burns and expect that the oven is ready to use. Have already cooked some bases and potatoes successfully.
Filled in the cracks with a clay slurry.
Question: I have several buckets of clay/vermiculite left over. Should I use this to thicken the insulation layer?
My concern is that the insulation layer is too dry.

[cobblerdave]

Re: New Earth oven build Melbourne

G'day
I'm not sure what you mean when you say the insulation layer is to dry. I'm taking it to mean the insulation layer is soft and easy dented with you finger. If this is the case it just the nature of pearlite. Your lime sand render should protect it.
If you going to include more insulation just be aware it will be introducing more water back into the structure. And of course it will be sucked to the dryer parts of your oven as is the nature of water . It will set your drying back a bit .
You'll discover that the inside of the clay shell has now set hard and you can give it a good tap with your knuckles and it has a satisfying ring to it .
The clay is not fired or sintered but has gone through a process of high dehydration. The temps between 350 C and 500C not only take out the water that is between the clay particules but also that in the clay itself. The clay then can't be rewet and return to moldable clay again. This will only extend a small way into clay body itself and not completely through it .
I'm in no way an expert but noticed this and did some investigation on what was happening.
Glad to hear that your using the heat from the drying fire to cook with. Its makes the time spent in drying you oven at bit easier to take if you produce something tasty.
Regards Dave

[MWP]

Re: New Earth oven build Melbourne

All finsihed. 10 months work involving bricklaying, researching, welding, grinding, rendering, drilling, sawing, digging. Now for the pizzas!
Infernorama

[TropicalCoasting]

Re: New Earth oven build Melbourne

Stunning
Well done a rocket stove wok burner and a plancha too?
Thats the kind of setup I have in mind.