Oven opening size

[Tscarborough]

Re: Oven opening size

Make it as wide as the biggest thing you plan on putting into it. If you make 16" pizzas, you need 17", etc.

[yorkshireknight]

Re: Oven opening size

Hi Mikku, from the other side of the world,

Thanks for your prompt reply. I am at the stage of laying the floor and therefor wanted reassurance over the opening after seeing Keiths post.

My internal diameter will be 81cm and have just been outside with a mock up opening to see if I can manoeuvre a paddle inside a 16 inch opening and pleased to say it seems ok.
This is my second attempt at the floor, I do not access to those wonderful chop saws etc I have to make do with a angle grinder and so getting a clean cut is proving very difficult.
Glad to hear you are enjoying the fruits of your endevours already albeit not fully completed.
Ciao
Paul

Thank you for your kind help, I intend to make pizzas eventually and a little bread and slow roasts,

[mikku]

Re: Oven opening size

Get as big width as you feel your construction above can support. I do not think that there is any rule for width, only ration of interior height to door height.

My dome is 750mm interior dimension...plenty for pizza. If you are going to make bread, in my opinion...I would go with a barrel design for more usable space.. eliminating hard to get at spaces within the oven.

Mine is not completed but it produces a lot of good things already--just learning the temperatures and times required---but way too early ---just guessing and getting a lot of good advice and support from Kamagawa sensei.

You have to guess how you will use your oven initially and have to settle with the results once it is finished. Best advice I can give... if you have an abundant supply of firewood--build bigger! If not---build smaller. If you are only going to produce things for your own consumption--build smaller. but build as much mass as possible, insulate twice as much as you first anticipate and you will only be 50% underinsulated with your end result.

I do not check threads as much as I should but I did not get any alert that this thread was replied to...

Just another voice replying from another side of the world in Japan.

[yorkshireknight]

Re: Oven opening size

Hi Keith Just come across your post, I too am building a 32'' and I too thought of a 16'' opening, I see you didn't get a reply to your question, but what size did you plump for in the end and did it work out fine for getting stuff in and out?

Many Thanks

Paul

[kstronach]

Re: Oven opening size

Hi,

I am just about to set out my cooking floor and opening and wanted some advice on the width of the opening. I had planned on a 32 inch oven with a opening of 16" by 10" in an arch, yesterday I made a form of this size to build around and I'm now concerned it will be to small (in width) and will make loading and tending the fire etc arkward.

Do you think I could go wider with my opening on a 32" oven?

Or would I be better upping my oven size to 34" or could possibly go to 36" would have to have a measure up!

What size openings do people have for there ovens? And are you happy with them?

Also will this get seen here or would I be better starting a new thread on opening width?

Thanks

Keith

[mikku]

Re: Oven opening size

I should qualify the metal frame making a little--my best friend in Japan has a fabrication business. "We" worked together at his shop and made the frame.
I brought it back to my small workspace, sanded it and primed it last night! I do not have any welding stuff of my own in Japan!

mikku

[mikku]

Re: Oven opening size

Hello again,
Missed lunch today and just stopped for coffee now. I cannot see outside from my workshop--all windows are obscure glass so I do not know when the rain ended, actually partially cleared up.

Here is the deal with the structural slab. I do not know how the WFO will be supported or installed in the future or even its' location at my house. So, yesterday I made a steel frame from 75x75x6mm angle with holes punched where future steel legs might attach and nuts welded inside at those locations. Also, did drillings and tappings for bolts to attach the plywood bottom and perimeter forms. My workspace is heated so I will pour the slab this week, get some heavy duty casters to put under it and be able to shuffle it around while I proceed with the oven building. My intention is to build everything indoors under controlled conditions and only bring it outdoors when it is time to fire the refractory for setting it up--then back indoors for dome insulation and the rest.

A neighbor down the road has a forklift so we will be able to move it indoors and outdoors as necessary.

I will be putting a lot of rebar, spaced closely and will use a receipe for high strength concrete. Have to talk to the Readymix company for the proportions and mix it at my place using a heavy duty drill like a tile setter uses. It is really quick mixing and you can make just what is necessary from scratch materials.

Still have to figure out the insulation detail ?? Source for fiber mat.

Did you have experience with brick before doing your oven? I had none so that is why I decided on refractory castable instead.

thanks for your input
Mikku

[Laurentius]

Re: Oven opening size

You're welcome. Those were the only photos. I have 2" of ceramic fiber boards under the hearth and 3 blanket around the dome. Only the oven itself are firebricks, its supported on standard blocks, the outside is rendered with stucco. Do you plan to pour your slab before the spring? Have it started snowing, yet? Here the rain has stopped.

[mikku]

Re: Oven opening size

Thank you again Laurentius,
Searched back some of your threads and found your build as it was just finished. Looks beautiful!
Are there other threads that showed while you were building it?
Like what is your insulation under firebrick and thickness?
also what is your dome and rest of oven made of ? All firebrick?
finally, what total thickness or number of layers of ceramic fiber did you use?
Lots of questions! Also saw that you are in Chiba-ken...shucks we are almost neighbors in this country! A working oven is still way off for me.. today is making the forms for structural slab (indoors)! Looks like we will get snow later today but it is raining here now.
Thanks again
Mikku

[Laurentius]

Re: Oven opening size

Hi Mikku,

Komari, is a good source for horticulture perlite/vermiculite. I didn't use either in my oven.
My fire bricks came from Joyful Honday and they were less than Y150 per brick. A kiln owner lead me my ceramic fiber blankets and boards nothing was as expensive as the prices I've seen quoted by the people stateside and down under, go figure.

[mikku]

Re: Oven opening size

Hello Laurentius
I am surprised! Another English speaker,living here,with an interest in WFO and with the skills or motivation to build one! Each quality makes the community smaller and smaller (very small percentage of population)! In any case great hearing from you.

Right now Perlite is high on my list, the stuff I found is both "B" and "C" grade
with "C" being the larger particle. This is from a local specialty masonry retailer. He had some in stock and could order more quickly. I will talk to one of the guys who grows and sells "vegetable transplants" to see if he could locate horticulture perlite/vermiculite for me.

Then there is the fire brick and ceramic fiber products. I found sourcing but need to compare prices. To date, I haven't made a trip to the Joyful Honda in our area.

My area has kilns for the processing of copper so everything necessary for WFO making should be available. I think that the people who repair them are no longer local. Also there are a lot of ceramic kilns not too far away, I think the town is called Mito?

Any insight you can give for locating products would be great. I like to research price as much as possible--money is always hard coming in and fast going out! Talking to find the "best price" usually pays big rewards!

Thanks
Mikku

[Laurentius]

Re: Oven opening size

Hi Mikku,

I built my oven here in Japan and got everything that I needed, my oven is not casted. What are you having problems locating? Maybe I can help?

[mikku]

Re: Oven opening size

Short note:
I know that everything is available from Forno Bravo, but there is no dealer in Japan- closest are the guys down south in Australia--but toss up USA or Australia??? I know that a lot of the bricks sold throughout the world come from China as well as the ceramic fibers but most things from China require pretty large minimum orders (unless you get some sent as samples)... Duty is a killer as well as Freight and Customs inspections. Plus,plus,plus and pretty soon out of sight for costs!

Finding things locally or getting a Forno Bravo dealer locally are the options. Maybe in the future we will have a local guy to call!

cheers to all!
Mikku

[mikku]

Re: Oven opening size

Hello Wiley and thank you for all your help,
What I am making is entirely castable, the only part that will be brick is the floor of the oven and if I decide to make a decorative arch. I wish I could send a photo but my camera takes photos that are so large (2MB) each that even e-mailing sometimes is a problem.

The dome is in halves; the back half is just a dome (made using trapazoid shapes), sometimes the dome shape is called a trapezium...(there is a net page that shows how to calculate the piece sizes and angles.

The other half is the section with the oven opening. But this section extends away from the dome ..maybe 6" and as the dome slopes away, that distance gets larger. I formed a recess at this face to accept an inner door in the future.

The third piece of this WFO is the section containing the transition to the chimney. I made the casting so that it would overlap the #2 dome section at the opening by 2"--like a shiplap joint. I also made it slightly larger , maybe 1/4" on the sides. I planned on puting some kind of a fiber seal there that would make some kind of a thermal break between the oven itself and the transition/chimney/landing area. When the assembly is complete, there would be an outer door that would enclose the landing/transition/chimney section.

My thoughts are that the inner door is off for firing and baking things like pizza. The outer door would be closed for firing but with some kind of a air damper to control the amount of combustion. If I wanted to retain heat in the oven for bread baking--then the inner door would be placed in the recess provided.

I have not made any decision on the type of dome insulation yet. It all depends upon the price of the different products. I would like to use a ceramic fiber blanket for maybe 2" and then covered with perlite/portland insulation maybe another 4".

The area beneath the fire brick floor same undecided. Minimum 4" of perlite/portland. There again have to find the materials and prices. All this is a little more difficult locating in Japan and trying to communicate your needs to suppliers who up to now have not sold some of the products. A real learning curve.

Today was cutting metal to make a frame around the structural slab. I am making things indoors because of the weather and then will bring it outside to its final destination when the weather permits.

As far as the dome goes, all surfaces: dome, interior entrance, and transition to outer door opening will have the same specs for insulation. Final coat some type of stucco mixture for semi-waterproofing. There will have to be some type of roof to protect the entire WFO from the elements. We get huge amounts of rain here June and July.

Thanks again ---sounds like you really enjoy making great things to eat in your oven. I am looking forward to trying mine out this spring!

Yes, your input helps,
Mikku

[Wiley]

Re: Oven opening size

Mikku,
I don't see that there is any theoretical optimum distance. This is where it would be very hard to make a WFO totally heat tight. By that I mean the refractory dome is insulated everywhere save for where the brick transitions to the entrance (I'll look back but I think you referred to it as a tunnel). There will always be some heat loss thru the brick in this area and out the chimney. Now one can get very anal about some things but I think the loss thru the brick in this area is small, but honestly I have no data to support that contention.

Personally, designing this area so that one can easily place a door (hopefully insulated) to close off the interior of the WFO from the transition area is more important than making the area absolutely heat tight. Now for the disclaimer: In my WFO I made a wooden door that closes off the interior of the WFO from the transition/tunnel/landing. What I have was made as a temporary door. It was to test the concept. I was going (and perhaps will someday) to use it as a pattern and make a proper insulated door with some "art" etc. But as in many things in life, temporary which works often becomes permanent...well, at least for now. So far I have not found any pressing need for changing what I have, it's lasted several (like going on five) years. True, I cannot bake something two days after a firing but where I live wood is close to free and plentiful, I see little need. Besides pizza I've done turkeys and roasts and pork shoulders and baked and grilled and etc etc. It's easy and quick and fun and I could ask for very little more.

I would suggest making the entrance of such a size that one can easily "work" the entire area of the hearth. Not having a blind area, which is hard to clear of coals or ash or an errant roll which falls off the peel, would seem to be more of a goal.

Hope this helps,
Wiley