Greetings from South Africa!

[Renier]

Hi Guys and Girls!

I started a castable dome oven and hope that I have all my measurments right.........anyway here goes.

the dimensions of the mould as follows:

inside diameter = 900mm
Centre = 470mm high

Mouth = 450mm wide
300mm high
300mm deep

I hope this is correct as the cast has already been built.
Should have searched the net before I started but this is the dimensions I got from a friend

Cheers

[Renier]

Re: Greetings from South Africa!

Here's a few picture's of the mould.
hope to get your thoughts on this!
cool

[Renier]

Re: Greetings from South Africa!

[Renier]

Re: Greetings from South Africa!

[Renier]

Re: Greetings from South Africa!

In goes the surfboard foam and body putty to shape the dome!

[Renier]

Re: Greetings from South Africa!

Some sanding sealer and a fibreglass layer to firm things up a bit.



inside the mould the air hose to aid in the cast release.



and the air nozzel prior to sanding

[Renier]

Re: Greetings from South Africa!

will take some pic's soon
hope to hear from you guys
cheers and happy pizza's

[mr g]

Re: Greetings from South Africa!

Hi, looks realy good. Can you elaborate on the surfboard foam and the air nozzle please?

The dimensions are fine, however it doesn't look like you've allowed for a rebate for the door to rest against. The door needs to be on the oven side of the chimney. This way you can trap all the heat in when baking bread and roasts. When cooking pizzas the door is not required.

You can check out my castable oven at :
http://www.fornobravo.com/forum/f6/m...oven-9230.html
or just search for castable.

regards
Mr G

[Renier]

Re: Greetings from South Africa!

Hi Mr. G,

I used surfboard foam to form the dome as it is light weight and can easily be sanded down to the right shape, its far lighter than sand meaning I can move the mould around.
For strength I added a few layers of fiber glass to reinforce the foam so it doesn’t crush under the weight of the refractory cement and it seals all wood leaving the water in the cement until it cures properly.

I added the air nozzle to aid in the release of the cast, so just before a pour I will cover it using a circular sticker and then add oil,clingwrap or any other necessary releasing agent, once the cement is set I will connect the hose to a compressor witch will force air in between the mould and the cement hopefully aiding in the release.
As for the rebate I did add 25mm rebate but unfortunately it’s not on the oven side.

Could I perhaps make a door with a circular plate extension to block the flue or do I need to change the mould?

Mr G I see our dimensions are exactly the same.... thats a relief as I got it from a friend who introduced me to FB, he must have read your trhead....

cool thanks
for the feedback will update with pics asap.

[mr g]

Re: Greetings from South Africa!

G'day Renier, I think your proposal will do for keeping the heat in. Although it's not ideal because what you want is to insulate any surface that is exposed to the outside environment.
If it was my oven I guess I would spend the extra time and make the rebate on the oven side.

I'm sure whatever you decide is better than not having an oven at all though !!

Good luck.

Mr G

[Renier]

Re: Greetings from South Africa!

Thanks for the advice...

Will a wall thickness of 50mm refractory cement be enough?

[mr g]

Re: Greetings from South Africa!

We made nine ovens all with a thickness of 70mm - 80mm. It was one of my biggest points of concern. You have to weigh up the time it takes to heat up, the amount of heat you want to hold and how strong you want the refractory. All the advice I got from suppliers was that 75mm was a better bet than 50mm (strength wise).

As for the amount of heat that the refractory can store - it takes my oven about 1hr 45 mins to come to temp. but it can hold baking temperatures (250 down to 150 Celcius) for two days.



Hope that helps.

Cheers for now.
Mr G.

[Renier]

Re: Greetings from South Africa!

Hi Mr. G.

our refractory cement comes in 25 kg bags and according to the manufacturer
can handle about a 1600 deg.

Would this be ok an how many bags would I need?


Thanks

[Renier]

Re: Greetings from South Africa!

Ok just read in your thread that you used 12 - 13 bags
my wall thickness will be slightly thinner so I should use a bit less.....
either way just ordered 13 bags .....Whoa driving a 1000km George - Cape town and back to pick them up....There goes the savings acount! Yeah!

[lwood]

Re: Greetings from South Africa!

Renier, sorry to come in to this late, but I would also recommend a rebate or reveal. If your going to mass produce this it adds a lot to the oven. Even if it's just for yourself, it's nice to have for the door to fit tight into. The rebate outside the flue does nothing for you.