Small Pizza Oven.

[trenchn]

Evening Guys.
I am in the process of planning my new oven and am looking for advice.
I want to build it as follows and am after advice regarding the practicality of my plans.
I am planning on making a mound of sand, covering it in wet newspaper and then covering that in a thick, 100mm minimum, coating of a vermiculite and concrete mix. I'll then, cut a door, scoop the sand out and Bob's your uncle.
My questions are thus,
Will this work?
Do I need an insulation blanket?
Do I need chicken wire?
How do I stop it cracking?
All advice gratefully received.
Thanks
Nick

[Gulf]

Re: Small Pizza Oven.

This is not my area, but you need to do a little more research. It sounds like you are placing an insulating layer on the inside of your oven. I did not see a mention of insulation under the sand mold or what floor material you intend to use . I am sure that someone else can direct you on a castable build.

You do need to download the oven plans from the FB Store.

[Tscarborough]

Re: Small Pizza Oven.

As stated, you need to begin with an insulating perlcrete base, then a shell of NON-INSULATING refractory, then another layer of perlcrete insulation. Bob will then be your Uncle.

[trenchn]

Re: Small Pizza Oven.

Sorry Guys, You're right, I should have said. My base will be made of heat retaining fire bricks from inside an old storage heater. These are extremely dense and retain heat very well. What would an alternative to this be?
What mix do I need for the perlcrete? We have vermiculite in the UK, which seems to be the same as perlite.
Look forward to reading your replies. I enjoy the planning almost as much as the build.

[david s]

Re: Small Pizza Oven.

The insulation under the floor, if using vermiculite, needs to be around 100 mm thick and the brew is 5 parts vermiculite, one part cement, three parts water by volume. If casting a dome over a sand mould you need to obtain a dense castable refractory from a refractory supplier. For a small dome 2" thick is adequate.

[mrchipster]

Re: Small Pizza Oven.

The insulation under the floor, if using vermiculite, needs to be around 100 mm thick and the brew is 5 parts vermiculite, one part cement, three parts water by volume. If casting a dome over a sand mould you need to obtain a dense castable refractory from a refractory supplier. For a small dome 2" thick is adequate.

Also after forming your sand mold layer it with wet newsprint to create a mold release for the sand and to make a nice smooth interior. The newsprint will burn out later.

Chip

[david s]

Re: Small Pizza Oven.

Sorry Guys, You're right, I should have said. My base will be made of heat retaining fire bricks from inside an old storage heater. These are extremely dense and retain heat very well. What would an alternative to this be?
What mix do I need for the perlcrete? We have vermiculite in the UK, which seems to be the same as perlite.
Look forward to reading your replies. I enjoy the planning almost as much as the build.

Be careful of the heat bank bricks, they may not be suitable because in that application they are not subject to high temperatures. Although I have heard of folk in the U K having used them successfully.

You can use either perlite or vermiculite. I discovered that a 50/50 mix of each produces a more workable mix than either of them alone, but can't explain why this would be so.