Clay Oven on Verandah

[david s]

Re: Clay Oven on Verandah

The heat beads are also great because they don't flame up and release their energy quickly. When the oven is new and contains moisture it is a bitch to fire. The fire is hard to keep going. Try a gas burner.

[BackyardPermaculture]

Oven now insulated

My cob oven is getting a lot closer to being finished - I've made most of the enclosure and completed the insulation.

The enclosure is fairly standard - metal framing with FC sheeting.

Insulation is 50mm thick rockwool, and loose vermiculite. This rockwool insulates really effectively; I've got one layer over everything and a second layer on top. I then poured loose vermiculite to fill up the sides.

I ran a much bigger fire last night; lots of water came out, which meant the top of the rockwool got hot and steamy. We still managed to cook chicken legs and steak over corn cobs - have never had such delicious corn!

[david s]

Re: Clay Oven on Verandah

Five days between finishing the cob and your first fire is way too quick. Rushed drying leads to warping and cracking in pottery and an oven is way thicker and will take longer. Can't emphasize enough the importance of taking it slow. I know it is hard because it is so exciting, but I'd hate to hear yo report that your oven walls have cracked and split from the centre. Slow down you move too fast, gotta make the ....

[BackyardPermaculture]

Re: Clay Oven on Verandah

OK, cool, but it's been 15 days and I've had small fires in there most of those days. Is that too soon? If so, how long? Thanks for the good advice, cheers, Mick.

[david s]

Re: Clay Oven on Verandah

Handbuilding clays that have a high proportion of aggregate seem to dry slower than those that have a low proportion. It's hard to say how long to wait, but I've found that thick sculptural work needs at least three weeks slow drying before attempting firing. The outside surface may appear dry, but the inside will still contain moisture. Most of my accidents from "blowing" have occurred at around 300 C You might be safe to try to avoid higher temps until you've fired it about 6 times. The smokey problem always occurs with a new, moist oven and it will just keep improving the more you use it. Try to keep the oven warm with heat beads which will provide a safer gentler heat until you're sure it's completely dry.

[BackyardPermaculture]

Re: Clay Oven on Verandah

OK, thanks, I'll keep going with smaller fires then.

[aussiepizzaman]

Re: Clay Oven on Verandah

hi Mick,
I was going to build something like your oven until i came across this site.
nice job so far and will be interesting to see if no further cracks appear.
all said and done each build is different , its the end result that we are after, an oven that can cook pizza and slow roast meals for our family and friends to enjoy.
good luck on the finish and enjoy your first pizza when you get to that stage.

regards Gary

[BackyardPermaculture]

Re: Clay Oven on Verandah

an oven that can cook pizza and slow roast meals for our family and friends to enjoy

.
I think mine is very close to that point

[simonoz]

Re: Clay Oven on Verandah

Hi

Have you finished the render coating yet?

I have an oven similar to yours yet my render coating, to try and weather proof the oven, cracks during a pizza cook.

Would be interested to see how you final finish coating behaves.

Simon.

[aussiepizzaman]

Re: Clay Oven on Verandah

hi Mick,
dont forget to post photos of your first meal and pizza,
you must be getting close to that now ?

regards Gary

[simonoz]

Re: Clay Oven on Verandah

Hi Mick,

A couple of pictures of my Clay oven build.

[BackyardPermaculture]

Re: Clay Oven on Verandah

Simon,

That looks really good! I like the paving you've got around the edges.

The more I look into rendering the clay, the more clear it seems that it's a bad idea to render it waterproof. Moisture needs to transpire through the clay and out through the render - which is why cob and adobe/mudbrick are usually rendered with lime renders and the like.

I've chosen to enclose mine in a steel-framed fibrous cement sheeting enclosure, which will be coated in a render paint from these guys:
http://www.appliedcoatingsystems.com.au/

I have the paint but haven't applied it yet - just finishing tiling around the top first. It's quite precarious trying to work on an oven on an upstairs deck!

Cheers, Mick

[simonoz]

Re: Clay Oven on Verandah

Hi Mick,

Attached couple more photos during the build, note that the render is only applied after the vermiculite layers. The render I have used is a lime based render and I have used a Bondcrete additive in the render.

The cracks I have in the render I think is a result of using the bondcrete and not having sufficient thickness (6mm). Plan to reapply over current render without the bondcrete and additional lime ratio using thickness of approx 15mm.

Simon

[BackyardPermaculture]

Re: Clay Oven on Verandah

Hi Simon,

I've not actually applied that kind of render before, but it sounds like it may be too thin. I actually owned a mudbrick house for a few years, and it had been rendered with a lime-based render with bondcrete added. That was a really nice surface (well protected from rain by a wide verandah) but since I didn't apply it I don't know too much about specific thicknesses etc.

Someone around this forum is bound to know something though...

Cheers,
Mick

[BackyardPermaculture]

First Pizzas Cooked

Finally cooking

I've been running some fairly hot and long fires, and cooking chicken etc., but tonight was finally the night for pizza!

The top-down fire worked really well, except that in the middle tier I had some framing timber offcuts (untreated pine) that smoked like crazy.

I used Peter Reinhart's recipe for pizza dough; found the resulting dough a bit tricky to handle but it puffed up really well and tasted great. I burnt the edges on one side - need to get a turning peel at some point.

Cheers,
Mick