Alan Scott oven in sydney

[Polo]

Re: Alan Scott oven in sydney

Well i had a good talking to by a friend who is an expert in this field and i will definately be changing things up somewhat.I'll be going for a hybrid version of the original design.Barrel vault type oven with approx. 75mm thermal mass all round and close to 150mm of insulation.Unlike Alan scotts design i will be putting the insulation over the hearth slab not under it,meaning i no longer need to design a suspended type hearth slab,it could just sit of the existing concrete blockwork.I will actually probably end up with a slightly bigger oven internally overall so thats also good.

Thanks to all who pushed me to revise my original idea.

Polo,i definately see the advantages of an oven like yours and like you say its also very efficient in the fact you need not fire it as often but i dont think ill be needing to be cooking throughout the week.I see myself as a weekend cook for when people come over etc.So i think i quicker fire up time and still a decent amount of retained heat time will be ideal for my purposes.

I'll keep you guys updated.
Cheers,John.

Sounds like you are making the right choice for yourself. I only commented so you could get the real life numbers from someone who has nad uses a higher mass oven.

In the end you need to build something that is suitable to your needs and not someone elses. Good luck on your build

[chubbybones]

Re: Alan Scott oven in sydney

Thanks crawfish,
Looks like we are on the right track then.

I did a quick mockup today and quickly realised that what my friend said to me was true.I will need more overall length,an extra 150mm to the hearth slab.I will just cantilever it off the concrete blocks.

[Crawfish fest]

Re: Alan Scott oven in sydney

Check out this thread.
http://www.fornobravo.com/forum/f16/...hot-19872.html

[Crawfish fest]

Re: Alan Scott oven in sydney

That's how mine is done.
I have a large flue, it drafts nicely
I am learning as i go along
My dome bricks are flat side down, not edge side down

[chubbybones]

Re: Alan Scott oven in sydney

It might be a bit early to be talking about chimney's at this stage but i guess i'd like to set out the dimensions of the final build while i still have the opportunity to extend the hearth slab over the blockwork.This was another very helpful tip my friend gave me.
So to finish the mockup i need to figure out where the oven ends and where the chimney opening begins.

I was thinking of making that transition as per scotts design like this ,
Any thought's ?

[Crawfish fest]

Re: Alan Scott oven in sydney

Yes, the walls are made with the sides touching.
This is my build http://www.fornobravo.com/forum/3/bu...r-19728-2.html
As u can see, in one pic i had the side walls and hearth bricks as the plans showed
We changed that out.

[chubbybones]

Re: Alan Scott oven in sydney

Hi Crawfish,
So you did basically what i want to do?
Are your walls and hearth now 75 mm?(ie: 3 inches).
Im sort of doing a mockup on the floor to see where things will go.
I need to figure out inner and outer arch and best way to combine them
to make the flue chimney.Surely there are minimum standards in flue dimensions t oallow for efficient draw from the oven.Ill have to look into that.
Also high did you come up on the walls before beginning your arch?
Good to see someone else in my predicament
Cheers,John

I used the Alan Scott Design.
I had the hearth and side wall bricks as the plans stated. The dome was not up yet.
Several guys here suggested this would be too much mass for an occasional Pizza
We went back and changed the bricks for less mass.
I am so glad I did.
Ihave 4-5" of vermicrete under the hearth
The oven is in the curing stage, without insulation yet.
I did have a crack open up.
We should be finishing up in a few weeks.
I am really happy with it so far
good luck
michael

[Crawfish fest]

Re: Alan Scott oven in sydney

I used the Alan Scott Design.
I had the hearth and side wall bricks as the plans stated. The dome was not up yet.
Several guys here suggested this would be too much mass for an occasional Pizza
We went back and changed the bricks for less mass.
I am so glad I did.
Ihave 4-5" of vermicrete under the hearth
The oven is in the curing stage, without insulation yet.
I did have a crack open up.
We should be finishing up in a few weeks.
I am really happy with it so far
good luck
michael

Well i had a good talking to by a friend who is an expert in this field and i will definately be changing things up somewhat.I'll be going for a hybrid version of the original design.Barrel vault type oven with approx. 75mm thermal mass all round and close to 150mm of insulation.Unlike Alan scotts design i will be putting the insulation over the hearth slab not under it,meaning i no longer need to design a suspended type hearth slab,it could just sit of the existing concrete blockwork.I will actually probably end up with a slightly bigger oven internally overall so thats also good.

Thanks to all who pushed me to revise my original idea.

Polo,i definately see the advantages of an oven like yours and like you say its also very efficient in the fact you need not fire it as often but i dont think ill be needing to be cooking throughout the week.I see myself as a weekend cook for when people come over etc.So i think i quicker fire up time and still a decent amount of retained heat time will be ideal for my purposes.

I'll keep you guys updated.
Cheers,John.

[Laurentius]

Re: Alan Scott oven in sydney

I'll give the straight scoop on an Alan Scott oven that is built from his plans.

It will indeed take more wood to reach pizza temperatures, but it will get there. The "forest of wood" analogy is a poor one. As a matter of fact I would dare say that one who fires their pompeii oven three times a week to make a few pizzas is deforesting the planet much more quickly than I am firing it once and baking all week.

My oven is a 32"x38" hearth dimension oven with 7" of mass all around. It will take me 5 hours of firing to reach 800 - 900 F (that is a temperature read at 1" into the hearth brick). It takes longer to saturate the oven to 4" deep, but that is not necessary for baking a few pizzas.

I use my oven prety much exclusively for bread baking and the amount of heat it stores is incredible. If you are building the oven to make a few pizzas once a week, I agree that a higher mass oven is a waste. If you are planning on using the retained heat to bake and cook throughout the week, then this is the right choice. If I bake on Sunday morning (550 F) the oven is still at 110 F when I light the fire to bake a week later. (saturated temperatures for my oven are read at 4" into the masonry)

Hi Polo,

Most of our ovens are on par with your, especially those of us who choose ceramic fiber boards and blankets, and didn't build primarily for pizzas.

[chubbybones]

Re: Alan Scott oven in sydney

Well i had a good talking to by a friend who is an expert in this field and i will definately be changing things up somewhat.I'll be going for a hybrid version of the original design.Barrel vault type oven with approx. 75mm thermal mass all round and close to 150mm of insulation.Unlike Alan scotts design i will be putting the insulation over the hearth slab not under it,meaning i no longer need to design a suspended type hearth slab,it could just sit of the existing concrete blockwork.I will actually probably end up with a slightly bigger oven internally overall so thats also good.

Thanks to all who pushed me to revise my original idea.

Polo,i definately see the advantages of an oven like yours and like you say its also very efficient in the fact you need not fire it as often but i dont think ill be needing to be cooking throughout the week.I see myself as a weekend cook for when people come over etc.So i think i quicker fire up time and still a decent amount of retained heat time will be ideal for my purposes.

I'll keep you guys updated.
Cheers,John.

[Polo]

Re: Alan Scott oven in sydney

I'll give the straight scoop on an Alan Scott oven that is built from his plans.

It will indeed take more wood to reach pizza temperatures, but it will get there. The "forest of wood" analogy is a poor one. As a matter of fact I would dare say that one who fires their pompeii oven three times a week to make a few pizzas is deforesting the planet much more quickly than I am firing it once and baking all week.

My oven is a 32"x38" hearth dimension oven with 7" of mass all around. It will take me 5 hours of firing to reach 800 - 900 F (that is a temperature read at 1" into the hearth brick). It takes longer to saturate the oven to 4" deep, but that is not necessary for baking a few pizzas.

I use my oven prety much exclusively for bread baking and the amount of heat it stores is incredible. If you are building the oven to make a few pizzas once a week, I agree that a higher mass oven is a waste. If you are planning on using the retained heat to bake and cook throughout the week, then this is the right choice. If I bake on Sunday morning (550 F) the oven is still at 110 F when I light the fire to bake a week later. (saturated temperatures for my oven are read at 4" into the masonry)

[cobblerdave]

Re: Alan Scott oven in sydney

I doubt it will ever get hot enough for pizza if that is what your aim is.
There have been lots of threads started by ppl who have built the AS oven and they all complain that it never gets hot enough.

Anyway, build it and report back.

Gudday
Al build an Allan Scott / Allan watt (aussie) inspired oven.
Then rebuilt it .... Check the link on the bottom of his posts.
It's not a true "forno" oven. Lower mass more insulation,though.
Regards dave

[brickie in oz]

Re: Alan Scott oven in sydney

Hi brissie,
I think if i go for a thermal mass of 176mm (7'') in the floor( firebrick+hearth slab) and 126mm (5'') in the walls(red brick + concrete cladding) , it should suffice.As for insulation , i will probably now end up putting 100mm (4'') under the hearth slab and 75mm (3") around the walls.
Im not really too fussed if i end up using more fuel to get it going.

Cheers,John.

I doubt it will ever get hot enough for pizza if that is what your aim is.
There have been lots of threads started by ppl who have built the AS oven and they all complain that it never gets hot enough.

Anyway, build it and report back.

[chubbybones]

Re: Alan Scott oven in sydney

Hi brissie,
I think if i go for a thermal mass of 176mm (7'') in the floor( firebrick+hearth slab) and 126mm (5'') in the walls(red brick + concrete cladding) , it should suffice.As for insulation , i will probably now end up putting 100mm (4'') under the hearth slab and 75mm (3") around the walls.
Im not really too fussed if i end up using more fuel to get it going.

Cheers,John.

[brissie]

Re: Alan Scott oven in sydney

Ok,so do you guys suggest i decrease the thermal mass and increase the insulation?

Having not completed my oven, but doing the research, and knowing basic physics, I have come to the conclusion if you want to save energy (wood) and have quick heat up times ~ 1 hour, you need good insulation and not as much thermal mass.

Generally to get to this point, many people use a minimum of 50mm ceramic fibre + more vermiculite concrete insulation, if you have space for the extra padding. Wall thickness is half a brick, or 50 to 80mm castable for the dome. 50mm calsil board under the hearth bricks. Calsil board can be substituted with vermiculite concrete. However if bread is the main aim then more mass is recommended.

It really depend on what you want, but I would not skimp on insulation, and remember that the more thermal mass, it will take longer to heat but allow you to bake for a longer time. In a home situation to much mass may be a liability.