Pompeii Oven with two openings???

[Piet Pompeii]

I'm looking for some advice:

We're building a kitchen, and plan to install a 42" Pompeii oven based on the Forno Bravo plans.

To save space the oven will straddle an exterior wall, with half outside and half inside the building.

My question is this:
Would it be possible to build two openings to the oven? One to service the outside entertainment area, and the other the kitchen.
Each opening would have its own chimney.
Each chimney would have a damper to seal it off.
We would only use one opening at a time.
Care would be taken to have snug-fitting doors, well insulated.
If this is possible, it will make the oven so much more useful!

I look forward to your comments.

Many thanks,

Jadon Allen

[Piet Pompeii]

Re: Pompeii Oven with two openings???

To make my question a bit clearer:
I have no doubt that it is physically possible to build, but my concerns relate to how the heat retention properties of the oven may be affected.

Thanks.

[david s]

Re: Pompeii Oven with two openings???

Yes, I"m sure it would work. Many kilns are built with dual entry ports and actually achieve better circulation because of it. I think it would probably work with both doors open, but if you have the facility to close either doors or flues you could easily experiment around. The downside will be that the oven probably won't hold heat as well as its single doored cousin, but the advantages may well outweigh that problem.
It could be a handy entry point for a burglar!

[Piet Pompeii]

Re: Pompeii Oven with two openings???

Thanks David.
That's a very valid point regarding the burglar access! I never even thought of that. I would have to make the outside door lockable...
Or keep the fire cooking hot!

[trapper]

Re: Pompeii Oven with two openings???

An additional advantage I see is that you would only have to load the oven with wood from the outside opening, thus keeping all the mess associated with storing and handling firewood outside.

Don't forget to post picks of the build.

[Bookemdanno]

Re: Pompeii Oven with two openings???

Make the doors heavy, and maybe from castable refactory cement, then they are simply a brick door. Insulate them well with similar layers to the oven, and off you go!

[david s]

Re: Pompeii Oven with two openings???

Make the doors heavy, and maybe from castable refactory cement, then they are simply a brick door. Insulate them well with similar layers to the oven, and off you go!

Impractical.You'd need a forklift to remove or place the door.Dense castable refractory is the same density as concrete.

[RTflorida]

Re: Pompeii Oven with two openings???

I am glad to see someone is seriously considering the dual opening. For a VERY brief moment I had the idea early on. One quick explanation to my wife that she would be loosing her dining room to a pizza prep area and the bay window overlooking the pool would be a masonry oven and she pointed to the back yard. I think I also struck a nerve about how the flue would have to be cut though the existing finished lanai roof. She didn't say word, just shook her head and pointed to the yard.

I hope you make a go of it, I may have a chance to try if someone steps up with a good build first.

RT

[Piet Pompeii]

Re: Pompeii Oven with two openings???

Thanks for the replies.

RT, I know just what you are talking about! Shake of the head and point. Game over.

(Terminology may be incorrect
At this point my main concern is whether the thermal mass (ability to retain heat) of the oven will be compromised by having two openings.
I am pretty sure a well insulated fairly light-weight door could be made, so I don't think insulation is an issue.

I also doubt that I'll juggle between doors too much, using the outdoor one in the summer and the inside one during the colder seasons, so if the closed door is a bit heavy this may not be a problem.
Having said that, I am hoping the oven will work with normal steel doors, allowing us to make the fire and clean the oven from the outside, even if we are cooking inside.

Anyone prepared to put their head on a block and make the call? There must be ways to increase the thermal mass if this will be necessary.

If the oven does turn out to be a failure, surely I can then just brick up one of the openings?

Cheers!

[Piet Pompeii]

Re: Pompeii Oven with two openings???



Here's a pic of the foundations. The main wall runs through the middle as you can see.
(Don't panic about the shape, the area of the circle can fit the oven and vent landings.)

[cobblerdave]

Re: Pompeii Oven with two openings???

Gudday
I have seen an WFO with 2 entrances in operation too. It was at the Brisbane show and it was inside a building. It was mounted on a trailer so it was a fair size 4' to 5' foot so you expext the oven was at least 42". The entrance I could see at the front was wide and a lot lower than you would have expected for the size of the oven even if it had a very low dome. And it had no chimney! When I bent down and looked in the inside of the oven there was an other open entrance at the back and I'm betting that one would have been the 63 per cent high. The rear of the oven was hidden as they had some set up to remove the smoke. I asked the operater about the two entrance and she said the smaller door was blocked when the oven was out in the open air and a chimney fitted to the larger.
Sorry I have little more details to tell you but I though you might be interested the difference in entrance heights and the lack of chimney on the smaller. Lots of commercial ovens like the old bread ovens have no chimney at the entrance and an internal chimney entrance set at the "63" per cent of dome height

Regards Dave

[david s]

Re: Pompeii Oven with two openings???

I guess all the smoke will tend to want to exit out the higher door, leaving the lower door smoke free and allow the operator closer access to the inner oven for easier operation with shorter handled tools etc. Clever.

[Bookemdanno]

Re: Pompeii Oven with two openings???

I still think a castable door will work.
Its going to be, what, 12" x 19" x4" and not opened and closed continually, more of a removable bung. Maybe even split the layers, a castable bung to replace the oven wall and keep thermal mass, then a insualtion bung, with a lockable outer shell for security.
It seems as it'll be a seasonal requirement. Two study handles cast into the refactory will provide the means to remove it. I'd mock up a section and cast it with concreting sand to give an idea of weight, etc. You look like you have plenty of building materials handy?
If you wanted a lightweight door, a usual metal, insulation, wood composite will do, but thermal mass is reduced. You'll need weight for that.
You'll always end up with a compromise, as you're attempting a radical design change.

[Piet Pompeii]

Re: Pompeii Oven with two openings???

"You'll always end up with a compromise, as you're attempting a radical design change."

This is what scares me. These ovens are a heck of a lot of work.
I don't want to be an idiot and try something that is a total waste of time and money due to a intrinsically flawed design.

[cobblerdave]

Re: Pompeii Oven with two openings???

Gudday
All ovens are different like their owners . I have cooked ... No rather helped cook in a few different ovens and their owners are the resident experts. You get used to your own. I myself don't think your going to have any trouble with loss of mass an opening represents only a small amount. The only trouble is if you fail to insulate ....all the non performing ovens you hear about on the forum the problem is lack of insulation not lack of mass

Regards dave