Best Oven for my needs and wants

[themess]

HI All, 

Rank Newbie here.

Im looking for advice on a pizza oven build.

1) Id like to do slow over night cooking as well as normal sort of cooking of various foods including pizza obviously. Which design would be the best way to do it? Brick or refractory cement and perlite / vermiculite?

2) If it was done the later what would be the recommended build thickness interms of walls / top / insulation etc?

3) what size oven internally would be the most appropriate for this type of oven?

Any info on this would be greatly appreciated.

Thanks in advance

[fox]

Brick built ovens are normally 4” thick and cast ovens are normally 2-2.5” thick.
Brick ovens are far more time consuming to build, slower to heat up but the high mass will stay warm for days.

Cast ovens are easier to build, heat up quickly and still hold heat for a long time depending on the amount and quality of the insulation.

So you need to decide on how much you want to spend and if you feel capable of building a full fire brick oven or assembling a pre cast oven.

The bigger the oven the more it cost and the longer it takes to heat up but with modern ceramic fibre insulatsion, things have greatly improved in recent years .
My own personal oven is a pre cast 32” oven with ceramic fibre all round insulation and i find that is a very capable oven and easily big enough for an average family.
It stays at cooking temperature for two days.

I have build much larger ovens in brick and cast, they can take two - four hours to heat up and use quite a bit of fuel but they will take up to four days to return back to ambient temperature !

Top quality materials can really add up though and a full spec 40” oven with base work can easily cost 10k plus !

[themess]

Cheers fox for that reply.

My intention has always been a cast oven using perlite with walls of approx 10cm 4" inches thick, with a ceramic blanket of about 30mm thick ontop and then covered with a fireproof / water proof render. I will use refractory cement and was thinking of using firebrick grog (broken up brick) in my perlite and cement mix. I would also then make a 50mm perlite base with firebricks (not sure of thickness yet probably the thickest i can get hold of) to sit on top of that. My oven internally im looking at about 35-36 inches (90cm). NOt sure of the chimney as yet.

Any advice on not to do from your experience would be awesome. I have pretty much watched every video on youtube to the point that no new ones are being shown.
I would be capable of building either cast or brick but am aware one is more costly than the other and certainly more time consuming.

Cheers

[fox]

Well I am afraid I can not recommend a perlite or vermiculite dome as the material is insulating and wont hold any heat for more than a few hours!
You need a high mass dome with insulation over that to hold in the stored heat .

In anycase it is much easier to work with high mass cement based mix than it is with perlite mix!
Honestly just forget casing the inner dome from an insulating mix, it wont last, it wont hold heat and be a waste of time and money.

There is a very acceptable method using a mix called Home Brew a mix of lime, Portland cement, fire clay and silica sand.
It had been proven over time and is well documented to last for many years.

The method involves making a suitable base and forming the dome from a pile of soft sand on top of the base  work, the home brew mix is then set over the dome of sand and the sand is dug out once the mix has cured.

You would then have a high mass inner dome that can be covered with insulation, you can use vermiculite to cover the dome or even better ceramic fibre mating.
Finally covering the insulation with a waterproof coat of cement.
That is a basic description but should set you up for more revision…..

[themess]

Outstanding!

This is the relevant info i was looking for. I have seen this type of construction done in videos except using bricks. I will research this method further much appreciated.
Cheers again

[fox]

Well there are lots of formats and styles of oven but if you want overnight cooking and slow cooking abilities then you need some mass.

The gym ball cast vermiculite ovens you see on youtube are not long lived and not suitable for holding heat for any length of time.

However if you want a bit of cheap fun and the ability to cook a few pizzas then those type of ovens will do the job especially if they have a proper fire brick floor, but the dome will break down and not last long.

The home brew style ovens are a big step up and in turn a bit more of an investment in time and labour, if you build one carefully there is no reason they wont last 10 years or more.

The next step up from home brew would be a pre cast refractory dome or a more complete refractory oven kit.
They will have high heat retention from a very dense, vibrated, high temperature material the thickness is normally only 50-60 mm so they heat up quite quickly but… loose heat very slowly.

Then you have brick ovens that can be made from clay bricks or top of the range full fire brick construction, this type of oven can really stay warm for days on end but take a lot of fuel to fully saturate the brick mass!

Of course the quality of the build, the skill of the builder and amount of investment will effect any build.