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Post by debbpic on Jul 9, 2013 12:33:35 GMT
Hi (ref: Complete Novice thread) We have now completed the base using sleepers which will then be topped off with 1/2" steel plate cut to fit completely on top and fixed down. What should we do next? We were thinking a base to cover the steel that is fireproof?? What would that be made from? Then build the actual oven on top. We want to use bricks and do it square. Is this OK? Does it have to be lined? If so with what? Chimney? Thermostat? Thanks Attachments:
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Post by rivergirl on Jul 9, 2013 12:48:43 GMT
Is that the base to your left in the photograph? I was thinking along the lines of a solid one when I suggested an infill of sand and bottles etc.........
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Post by swatson on Jul 9, 2013 12:54:34 GMT
You will need an insulation layer to prevent all the heat draining out of your hearth, you could go with a fine layer of sand and then a layer of Celcon blocks, these blocks are light weight with lots of air pockets and a great heat barrier. You would then lay another fine layer of sand and then your firebricks for your Hearth on top of that!
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Post by swatson on Jul 9, 2013 12:55:58 GMT
This is the Celcon blocks laid out on my build! Attachments:
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Post by debbpic on Jul 9, 2013 19:12:59 GMT
Is that the base to your left in the photograph? I was thinking along the lines of a solid one when I suggested an infill of sand and bottles etc......... It's very sturdy. They're sleepers and they're fixed together. I have a huge piece of steel to go on top. So I think it will be fine. We're going to store wood in the middle |
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Post by debbpic on Jul 9, 2013 19:18:45 GMT
What I need answers to are these two things:
1: does it have to be a dome shaped oven? With or without a door?
2. What is used for the actual base of the oven?
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Post by debbpic on Jul 9, 2013 19:24:21 GMT
Ok, I'm getting so muddled with all this stuff. I'm looking at the kiln linings website and I'm so confused to what we need.....minimum
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Post by kstronach on Jul 9, 2013 19:42:03 GMT
Hi, put your steel on top as you were going to then as swatson said use celcon blocks (i think that's a brand name, if you go toyour local builders merchants ask for thermalight blocks). Then just bed these blocks on top of your steel then on top of these goes you cooking floor ie, firebricks or storage heater bricks etc. One thing you may have to take in to account is how you are going to cover the edges of the thermalight blocks as you probably won't want them on show will you?
Keith
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Post by debbpic on Jul 10, 2013 9:08:35 GMT
Hi, put your steel on top as you were going to then as swatson said use celcon blocks (i think that's a brand name, if you go toyour local builders merchants ask for thermalight blocks). Then just bed these blocks on top of your steel then on top of these goes you cooking floor ie, firebricks or storage heater bricks etc. One thing you may have to take in to account is how you are going to cover the edges of the thermalight blocks as you probably won't want them on show will you? Keith Thank you Keith. BIG help  |
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Post by swatson on Jul 10, 2013 9:32:56 GMT
If you click on the link to my build at the bottom of my posts and go to page 3, you will see picture of the process from insulation brick to hearth brick.
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Post by faz on Jul 10, 2013 11:30:10 GMT
And remember, it is not just the floor of the oven but also the walls which need to be constructed on top of the insulation layer, as you are trying to stop heat flowing out of your oven in to your steel sheet where it will be lost.
The oven can be a dome or a barrel vault though it looks like the dimensions of your base would be more suited to a dome - take a look in the two parts of the forum dedicated to the two types of oven for ideas.
Being so close to the house I would also recommend that you put a decent sized chimney on to try and get the smoke to disperse - probably a twin wall stainless steel flue is best from a weight perspective, rather than a brick chimney with chimney pot.
My oven is about 10 feet from the house and there can be a lot of down draft if the weather is blustery or the wind is in the wrong direction.
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Post by bookemdanno on Jul 10, 2013 16:20:09 GMT
I think it'd still be worthwhile to make a full tabletop of sleepers before setting the steel.
Half an inch sounds strong enough, but you're going to place something like 2-3 people bang in the middle of it, and get it a little warm! If it flexes, so will your oven, and they don't like to flex at all.
Kilnlinings will do insulation boards too, like WDS Ultra and Calcium Silicate. These should give similar results but at half the thickness of Thermolite Blocks. Downside is that they cost more, and you'll have to wait for delivery. Definitely use Twin Walled Flue, Ebay can be a good resource for that.
Firebricks are the main choice for cooking floors, but Storage Heater bricks work well, as do old solid clay bricks.
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Post by cannyfradock on Jul 11, 2013 9:24:52 GMT
Deb I agree with Danno about putting some beams in the central part of your base....or at least 2 to spread the weight of the oven floor. I would also just use cheap fibre board or similar in place of the steel and place place thermolite blocks on flat on top of this. This will then be ready to build your oven and hearth bricks on. The top of the oven needs to be refractory bricks or clay bricks. If you tried to build it square you would have to use some sort of lintel to bridge across the 2 sides. this can be done with steel or re-enforced concrete lintels of which neither are good for holding heat, so that's why a dome (as in clay or Pompeii oven) or a Vault or Barrel oven are used in the construction of a Bread/Pizza oven as they are self supporting.....the only other way of building a square oven...as I see it would be to build up the side walls and make a shuttering for the top and use grog...or refractory concrete and pour a roof slab. This would still need some sort of strengthening bars? Have a look at this Vault oven build from Dave. It might give you some pointers... www.gardenoven.com/categories.php?cat_id=1 Terry |
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Post by debbpic on Jul 11, 2013 11:42:56 GMT
We have now topped the sleeper Jenga pile with the steel and cemented Thermalite blocks all over it.
We will now construct the oven and chimney. What can we get to line the inside of the oven? For the base we are using four large pizza "rounds" which can then be removed and cleaned and also makes cleaning out the oven easier.
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Post by cannyfradock on Jul 11, 2013 16:59:00 GMT
Debb You said.. "What can we get to line the inside of the oven?"...... I'm not sure how to put this, but I think you are missing the whole point of a bread/pizza oven. The actual floor and walls ARE the lining of your oven. That is why we recommend fire-bricks, but, reclaimed clay bricks have also been used very successfully. The only "lining" goes on the outside in the form of insulation layers. If you use fire-brick or clay brick or storage heater bricks......or even cob (in a clay oven) it will all function in a similar fashion. Once the oven has been slowly cured (lots of small firings) you can then put some serious heat into the oven. When warming during the firing process carbon or ash will collect on the surface of the dome. Once the oven reaches a certain temperature (about 500c?) the soot will start leaving the surface on the top of the dome. This can clearly be seen when using fire-bricks (because of their yellow/buff colour. The dome will then clear itself of ash .....and you can see the line of ash descending to the bottom of the dome. Once the dome is clear of soot you know the oven has enough massed heat. You then need to push your fire to the side, clean the hearth and wait half an hour or so for the oven to amass and hold all that heat. I've mentioned this process to help you see that the lining of the oven is the brick itself......if that makes sense. You also mentioned earlier...with or without a door......a recess or a rebate is formed between internal and external arch when people want to use their oven for bread baking. You may be able to see the rebate in this pic of an oven I built for my boss...  it's created by making the entrance arch a little bigger than the internal arch. This rebate makes it easier to jam the door against when baking bread......It doesn't have to be built in as a piece of fire-rope tacked onto the outside of your door will seal the oven (I'm a brickie so I always create a rebate when I build an oven for other people). Terry |
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