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rhondab01 08-12-2009 11:17 PM

oven dimensions
Hi - hope somebody's out there.
I've just started building an oven base from old bricks, but my dimensions are limited. The base will be about 110cm x 150cm.
Assuming a total thickness of 20cm for the walls, that means I will have an oven with an internal diameter of about 70cm.
Has anyone used an oven this small? I think it would be quite adequate, but all the ones I see on this site are so much bigger!
Alternatively, could I take the brick section of the walls right to the edge and form my insulating layer, which I'm planning on doing in clay and chopped straw, as an overhang, moulding it back in to meet the side wall of the base?
Then I could have an internal diameter of about 90cm.
Another possibility is somehow forming the concrete slab to extend beyond the sides of the brick base.
It's probably obvious, but please assume I'm a rank amateur if replying to this.
Thanks, Rhonda

Neil2 08-13-2009 03:43 PM

Re: oven dimensions
70 cm = 27 1/2 inches
90 cm = 35 inches.

I think you will be a lot happier with the larger size. Also, at the "pinch points" of the insulation layer, you can use the insulating blanket material. (go to your local dump and remove some from the liners of old electric ovens)

Mitchamus 08-13-2009 04:08 PM

Re: oven dimensions
Hi Rhonda,
I would just cast the slab larger than the base, and make the oven in the 90cm (or 1m) size.

70cm is on the small size, not unusable, but probably limiting.

hope this helps...

ratbagradio 08-13-2009 07:04 PM

Re: oven dimensions
How is the smaller size 'limiting'? Surely you have less space to heat? If the perspective was to cook one item at a time (or so many small)-- your deciding factor is space large enough for your item to bake -- to accept what ever hardware you cook in or the item -- its height and width. In that sense the size of your oven door would rule, wouldn't it, rather than the size of the oven? (eg: one figure suggested by Canadian research was a door height 63% of oven height)

The only limitation I can imagine with a smaller oven is that it would be more difficult for a baking item to share the space with a smoldering fire.

My everyday kitchen oven(electric) is much smaller than these figures....and I rely on that day in day out.Similarly a Dutch oven is as big or as small as the one you bought.

Unless there is some physical principle involved, ovens could be of any size -- although their shape should be ruled by the way hot air flows.

If you toured ovens world wide as the Breadhunter does seem to
Breadhunter's Blog: 4/13/08 - 4/20/08
Breadhunter's Blog: 5/4/08 - 5/11/08
size doesn't seem to be a constant.Although there is a mean I guess -- judging on these images -- esp for community ovens.

If I'm missing something I'll need to redraft my oven plans as I, like Rhonda, was planning a smaller oven.

Mitchamus 08-13-2009 07:11 PM

Re: oven dimensions

Originally Posted by ratbagradio (Post 61733)
How is the smaller size 'limiting'?..snip... your deciding factor is space large enough for your item to bake

hence 'limiting'...

6 roasting trays + room to spare = Christmas lunch taken care of:

sorry for the blur...

dmun 08-13-2009 07:37 PM

Re: oven dimensions
Your oven's heat control is the placement of the food. A tiny oven with a fire really only has one place. Mine is 36, and I really wouldn't want it much smaller.

david s 08-14-2009 12:28 AM

Re: oven dimensions
I'm a believer in small is beautiful. There are just so many advantages. Mine is 22" diam and I've cooked pizzas for 40+ parties. I's all a matter of oven management. Nearly all home cookers cook one pizza at a time anyway.

Rodneyf 08-14-2009 05:17 AM

Re: oven dimensions
Rhonda I built my base with the slab on top and the realised I need more space for my entry. My solution was to over hang my insultion slab to give the space I needed which has worked just fine. If you have a base and you can place a concrete slab on top that is properly reinforced you will have no problem with a 20cm over hang all around your base and that will give you the room to work with. Thake a look at the link below and you will see how I have a front and rear over hang, 41# shows the over hang. Good luck and you are amongst freinds here that are here to help. :D

Picasa Web Albums - rodneyaf - Pizza oven

rhondab01 08-15-2009 10:55 PM

Re: oven dimensions
Thanks to all for the responses - I think I've worked out what to do. I only need to extend the base a little on each side to build an oven with a 90cm (35 inch) diameter. The smaller size would be fine for closed oven cooking, but I think for fast cooking pizzas with a fire in the oven it might be a bit small. I am planning on having it up and running for my son's 18th - umpteen hungry boys waiting for a feed.
Since you've all helped to clarify this for me, I'd like to ask another one. One site I've looked at recommends against chimneys and vents, saying the oven draws better - cool air in at the bottom of the door, warm air out at the top - without one. Any thoughts?

brokencookie 08-15-2009 11:21 PM

Re: oven dimensions

Originally Posted by rhondab01 (Post 61845)
, saying the oven draws better - cool air in at the bottom of the door, warm air out at the top - without one. Any thoughts?

This only works if you don't mind smoke in your face while cooking. The collective wisdom of the forum says you absolutely need a chimney. There are also tons of threads discussing chimney size. You will need at least a 6 inch diameter flue. Also the taller the chimney the better the draw.
Maybe what they are talking about is a chimney in the middle of the oven. All of the Pompei ovens have the chimney over the entrance. Download the Pompei plans and look them over. They are free on the forno bravo site and contain a terrific treasure trove of practical oven information.

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