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Post by cannyfradock on May 10, 2013 15:34:43 GMT
nixie
Love your nice neat workmanship. There are quite a few different methods of creating that thermal layer below the hearth, but I always go down the same route. The insulation blocks are easy to lay, are very light, only cost about a quid each and can be cut with a normal handsaw.......and they work.
Terry
p.s......no problems with posting links when referring to a product or company that you have used.
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nixie
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Post by nixie on May 10, 2013 15:58:01 GMT
nixie Love your nice neat workmanship. Thanks, there some clever use of camera angles there to hide the worst bits . The sins should be covered by the rendering layer in the end hopefully. The blocks were nice and easy to lay, I only broke one and that was because I didn't get the cement flat enough before placing the block and stressed it too much. Think it was reading yours posts on here that led me to use these and it sounded so much easier and cheaper then some of the other solutions (bottles, insulating board). I'm trying to decide at the moment if I'm going to use cement, clay/sand mix or just sand under the insulation and oven floor layers.
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Woody
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Post by Woody on May 10, 2013 19:33:37 GMT
Hi Nixie, I am also looking to source some clay on the Internet as I don't have a local supply. I gave the guy a call from the the website you mentioned above and told him I am building a pizza oven. He recommended I buy the fireclay, www.castreekilns.co.uk/fireclay-531-p.asp as it is better for high temperatures. What do other people think, would fireclay be better? Thanks, Woody
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nixie
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Post by nixie on May 13, 2013 8:43:39 GMT
I'm no expert but will try and explain my choice of the terracotta. First up was a post on the 'Clay Oven' site (author is a member on here now I think). This was written by another clay/kiln retailer and indicates that a eathernware clay like terracotta is suitable, see clayoven.wordpress.com/2009/04/08/11-clay-clay-clay/. Next up I read somewhere that fire clay really wasn't that special, its just clay that is extracted from near coal seems I think, it does have a high alumina (??) content though. I can't remember where I read this though so treat it as such. Finally from what I've read one of the reasons for using fireclay is that it behaved better in terms of shrinkage/expansion when used neat. As I'm still intending to cut my clay with sharp sand I didn't think this was an issue because as I understand it the mixing of sand improves the shrinkage/expansion properties. I came to the conclusion that fireclay may well be better when used neat, but that works out expensive (in the article I linked above the author suggests 15 12.5 kg bags! expensive. By cutting 2:1 with sand my 6 12.5 kg bags should make more than enough clay). I will repeat though that I'm not an expert and I might be way off the mark.
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nixie
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Post by nixie on May 13, 2013 10:34:36 GMT
Didn't have the time to do much over the weekend, however did manage to layout my template, get an idea about the arch, and test lay the thermal mass layer. The template laid over the base. Getting an idea of the arch size. Actual arch side will be 4 bricks high, however 1 of these is to make up the thermal layer thickness. Then we have 2 different layouts for the thermal mass to asses coverage. I think I'll be going with the second and maybe cutting the corners off a couple of the blocks to fill in some gaps (maybe). This layer is going to be bedded on sand I think with clay around the edge to hold it in place. The proper oven floor will be on top of this, again with a sand layer in the middle. The floor is going to extend over the bricks in the arch to make one large floor, though I'm going to leave a gap (probably filled with insulation block) between the thermal mass and arch bricks. I'm intending to make the sand form to include the door straight away, partially to save clay, and because I think it'll save time and give the arch, porch, dome interface a better bond. As I'll need an extra insulation block to make the thermal break between the thermal mass and arch sub floor I may use other bits of the block between the arch and dome. It appears from the laying out that the arch bricks will penetrated the outer layer of the dome, I'm going to move the chimney into the arch (shown behind arch on plans) and will probably be using a more rectangular block I found in B&Q (can't see on their website though) instead of the double wall flue pipe I was thinking of using. Next up is laying the final 4 blocks of insulation (just laid in place in the pics) and then as I'm using ready mix cement I'm going to lay the arch base and start up the sides of the arch.
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Post by cannyfradock on May 13, 2013 11:30:29 GMT
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nixie
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Post by nixie on May 13, 2013 11:42:47 GMT
Hi Terry, Yeap it does, not copying honest . What was the internal diameter on that build? Looking at your thread it does look like I might be able to get away with flue pipe as a chimney. There is more room than I thought.
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Post by cannyfradock on May 13, 2013 14:09:00 GMT
Nixie
I can't remember exactly but those storage heater bricks are 210mm x 195mm so I would have pushed the maximum width possible for 4 of those blocks laid length ways....= 840mm. ....I think it was about 700mm internal dimensions.
You mentioned copying.....please do!!!. This forum was initially set up to help wood-fired oven enthusiasts build "their own" oven. We tend to go on a bit saying "please post pics....we love pics" We must have 100's of picture diary's of Pompeii, Vault and Clay oven builds on this and our old reference forum and most people trudge through these picture diary's and save or "favourite" 1 or 2 builds which they can relate to when building their own......at the click of a button.
This is what we are all about.....sharing..... And it works!
Terry
p.s....don't forget those pics
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Post by nordberg on May 13, 2013 15:22:30 GMT
Following this thread with great interest... Need to order my clay soon
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Post by rivergirl on May 13, 2013 18:56:07 GMT
I made a huge sand castle and I formed the mouth piece around the door ( a big mistake as , as it dried it tightened around the door making it really difficult to remove ) If I ever build another one ( not counting the beehive I want to knock up) I would do a brick arch for the mouth. I built the outer of mine onto patio slabs . the idea being that people could loll near the oven rest drinks and plates etc !! the reality is that the cats are usually sleeping there
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nixie
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Post by nixie on May 13, 2013 19:20:13 GMT
I'll be happy if the cats sleep there, better than the softtop on my car! I'm planning a BBQ next to the oven and am going to use a couple of IKEA chopping boards as work space and drink area.
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Post by turkey on May 13, 2013 20:05:34 GMT
looking good, you are getting very close to being able to play with clay and start the oven proper.
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nixie
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Post by nixie on May 13, 2013 20:42:37 GMT
Thanks, really looking forward to getting it done and doing some cooking.
Just a thought has anyone premixed the clay/sand on one day, stored it, and then used it another day.
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nixie
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Post by nixie on May 20, 2013 9:00:37 GMT
More progress this weekend. The insulation layer is now complete. I've started on the arch and the sub floor is now laid onto sand (with a bit of left over cement securing the edges). The arch is positioned so that it buts up to the outer edge of the inner dome. It will be partially covered (10cm) by the insulation layer. I've hopefully got enough fire bricks to extend all the way to the front of the arch as shown in the trial layout. The sub floor is slightly lower than the arch floor though so am going to either have to use sand again to pack it out, or maybe a clay mix. I'll probably use clay slip to hold the fire bricks onto the arch floor as this area is more exposed to knocks. In the last photo you can see the insulation gap between the sub floor and arch. This I'm going to put insulation block into. There will still be a thermal bridge across the oven floor, but hopefully the gap will help as the floor bricks aren't so thick.. Still not decided on the chimney design. Need to think about that this make a former for the rest of the arch (first 2 bricks done free hand ).
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Post by turkey on May 20, 2013 10:13:24 GMT
cracking progress. I would say if you can you might want to consider laying the hearth fire bricks at 45 degrees. This does involve more cutting and is more work but when its laid it will help you use the oven.
If you have a slight lip on the bricks as they are the pizza peel will hit it and stop, with the bricks at 45 degrees the flat blade of the peel will slide over slight irregularities a lot easier.
Its a very minor thing and if you are tight with the bricks you have it might be too risky to do, and you do look like you have a very flat stable base so getting the hearth bricks all level should not be so difficult here, but thought it best to voice the idea before you are too committed only to decide you might prefer that later.
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