Castable Pizza oven Smoker combo

[deejayoh]

This was one of the most impressive cast oven builds I have seen

https://community.fornobravo.com/for...-an-ohio-build

[Lburou]

I took some time and dug through my list of favorite castable ovens here on FB.com...Here are some additional links for you Fergo:

https://community.fornobravo.com/for...le-oven?t=9230
https://community.fornobravo.com/for...-japan?t=16707
https://community.fornobravo.com/for...m-texas?t=3397
https://community.fornobravo.com/for...ng-oven?t=9380

HTH

[fergo]

thanks for the links, very interesting reads

[Lburou]

Here is Sonomacast's cast oven thread...Very informative. HTH

[Toomulla]

only cheap things in Australia are the politicians and their opinion

[Lburou]

ok sounds like i might have to just keep my eye out for some cheaper firebricks and make it out of brick. thanks all

Here is a link to one cast oven here on FornoBravo.

I made a post about DIY Castable mix some time ago, here it is:

During a visit to my local refractory, I spoke with the owner and his engineer about a home made castable for my best friend working overseas where commercially prepackaged materials are not readily available. This is the home brew recipe they gave me -use at your own risk:

30% Ciment Fondu (calcium aluminate cement I'm sure you can get some)
60% Aggregate (#6 mesh -sizing 3mm down to powder)
5-10% Fine Sand
5-10% kyanite (crushed, Metamorphosed peri-aluminous sedimentary rock, optional, if not available locally-add more fine sand)

HTH

[david s]

Everything in Australia is expensive. A can of coke will cost you $5. We have a decent minimum wage here, apprentices drive around in $65K light trucks and everyone wants to be a millionaire.

[deejayoh]

It seems crazy to me that firebrick and refractory are so expensive in Australia - key component is alumina, and Australia is home of the worlds largest bauxite mining operations (and probably reserves too, I dunno). Sounds like a business opportunity!

[fergo]

No worries i will think over the options and look at some castables on here and decide which way i want to go.

[david s]

ok sounds like i might have to just keep my eye out for some cheaper firebricks and make it out of brick. thanks all

I am sorry if my previous post has put you off casting your own, that was not my intention. There have been many successful home built cast ovens that are way faster and cheaper to build than a brick oven. Research the forum to find examples. Search cast ovens. The easiest way is to cast over a sand mould and create a one piece dome. As previously mentioned there are a variety of options to use as your castable.

[fergo]

ok sounds like i might have to just keep my eye out for some cheaper firebricks and make it out of brick. thanks all

[david s]

Both vermiculite and perlite will withstand up to 1100 C. Anything north of that and they self distruct. As a WFO will only see temps of 600 C at tops on the surface facing the fire then they are both suitable for this application. However, when you add either of them to a mix they drastically reduce its strength. This results in a refractory mix that is susceptible to abrasion damage and fracture from minor impacts, especially if it's thin. In addition if Portland cement is used it won't be too long before the casting fails as Portland cement begins to give up at anything north of 300 C. You could use Portland/lime (home brew) for an improved result or better still use calcium aluminate cement (expensive). As previous posters have advised a dense castable refractory is a better solution, usually 2" thick which will heat relatively quickly and is enough thermal mass to allow retained heat cooking (roasting and baking with door in place). You can then add insulation layers over the top, either blanket, lean vermicrete, or both.

[fergo]

Hi all,

thanks for the response. I guess half of my question has been answered that i cannot make the oven just from vermiculite as it wont have the thermal mass. which i kind of figured but its nice to have this theory validated.

Which leads to the second part of my question. If i make a mold from vermiculite and then use castable refractory cement on the inside, how thick will it need to be to gain enough thermal mass.
As far as what i am likely to do it in, ribs, maybe bread. not three days later but maybe the next day.

so if i was to do say 2inch thick vermiculite dome, then cast say 2inch refractory castable inside would that retain the heat im looking for?

The reason i am looking at this route as fire bricks are not terribly easy to come by where i am, and if they are they are expensive.

[jonv]

I know the videos fergo is referring to and they do indeed show pizza ovens being made just from vermiculite and portland cement, slapped on over a form.

Fergo - there are lots of builds on youtube, some are good but others are not so helpful. Some of the designs and materials used are imo poor choices. I would ignore the videos and spend some more time on this forum, going through as many build threads as you can to get a good idea of the principles of good oven construction.

I'm sure one of the casting experts on here can help you with specific advice if you want to go that route. It won't be quite as easy as some of the videos suggest but performance and longevity should be much better.

[Les]

Just to clarify Deejay's response. Vermiculite IS a good material for an oven, but only for insulation. Fergo, you need mass ( i.e. brick, refact material, etc... ) Once that has absorbed the heat, you want to retain it - that's where the vermiculite comes into play. As far as thickness of your refractory wall - that depends on what you want to do. If it's just pizza, 1 inch would probably work. If you want to cook something 3 days after the fire - you need mass.