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Post by baileyhsi on Mar 13, 2013 21:00:58 GMT
So I made my foundation as big as I could with the space I have and I've come out with a width of 52". By my reckoning I need 3" gap to the edge, 3" vermecrete, 2" of thermal blanket and 4.5" fire brick on either side leaving me an oven diameter of 28" in the middle. Does this sound right?
Either way I'm well short of the silly size I was originally going for so will stick with a standard opening size for this project.
Working with this size oven what dimensions should I be looking at for the dome height, door height and door width? OBviously I'm still going for maximum door width if possible.
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Post by cannyfradock on Mar 13, 2013 21:50:35 GMT
Bailey By my reckoning you are still 1" short of your overall 52".....and you need a waterproof render to finish your dome. There is no need to leave a 3" gap at the edge. You can take the dome right to the very edge if you want so that will give you an extra 3" either side. Also, even though your footprint is 52" wide, you can make the slab wider if you want by using concrete lintels to overhang the walls.....or make a box shuttering to extend the walls. It's difficult to envisage your base as I'm not sure how much space you have when looking at your picture. The concrete slab can extend on one side only ....by as much as 6 or 8 " as long as you use re-bar. I'm not very good at tech drawing but I can knock up a detail of how to achieve this.....if you want. Your dome height should always be half the diameter of your oven. If you can "stretch" the slab so you can build an internal diameter of (sorry...back to metric)...90cm (roughly 3') then the height should be calculated to half it's diameter....45cm. The door height is 63% of the height of the oven....=28.35cm...or somewhere in that ballpark figure. I don't know of an equation for door width relating to dome width, but I recommend a 40cm ...or 16" door width for this size. As you want a maximum width of door opening size, you may be able to move the goalposts a little by making your dome more pear shaped than circular. The dome doesn't have to be an exact half circle or half cylinder....as long as the dome rings make a continuous ring, then you can make the dome oval if you want. Rado Hand of traditional.com has designed a similar oven. www.traditionaloven.com/pizza_wood_oven/pizza_oven_3.html Your options are still open. Terry
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Post by baileyhsi on Jul 15, 2013 18:13:30 GMT
Long time no see! Nearly four months ago I started but for one reason or another (kitchen ceiling broke, holidays, work, weather etc etc.) I haven't been able to carry on my work until now and I'm committed to getting a working oven by mid August. I got nearly two days work in over the weekend which means I managed to lay my lintels... ...before laying more blocks around the edge to house my ceylon blocks in the middle... Now I know it looks pretty wonky down the bottom left hand corner but I'm not too worried about that, I would say that one lesson I have learnt is not to assume that all building blocks bought from the same place at the same time are going to be exactly the same size! My maths have been thrown out more than once no when I've found a rogue block a couple of inches shorter than the rest. This added to my generally shonky work has made for some rough edges for sure but the base is sound I think. Next steps are to drop some sand on to the ceylon blocks before building the outer wall up another block and dropping bricks in the middle again before dropping more sand in and topping with vermicrete. Then I think I'll be ready for my hearth stone. I do think I'm going to chicken out on the pompei design and go for a barrel shaped design which I think will be easier for an unskilled man like me. Dimensions wise I have 135cm x 135 cm of space to play with and would still like to go for a large opening of 22", is this feasible? Also could an admin move this thread over to the correct forum section now I've made my mind up, sorry!
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Post by baileyhsi on Jul 15, 2013 20:03:08 GMT
OK so as I'm planning my next stage I have some questions...
What is the ideal ratio between width and length?
What is the ideal placing of the chimney in relation to the opening?
What is the ideal height in relation to the other dimensions? Most people just go for one or two bricks before the forming of the arch.
When in use do you get to use the full width of the oven with the fuel pushed to the back of the oven?
Also already changed my mind and will be going ceylon blocks then a layer of vermicrete then the red bricks then the hearth stone.
Unless someone tells me otherwise I'm going to go for...
24" internal width plus 2 walls at 4" each plus 2 thermal blankets at 4" each plus vermicrete and render sides at 4" each side giving me an external width of 48" with a couple of inches space on either side. Internal length should be 42" plus 4" wall plus 4" blanket plus 4" of vermicrete/render giving me an external length of 54".
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Post by baileyhsi on Jul 15, 2013 20:15:11 GMT
Sorry just going to carry on using this thread as a bit of a notepad for myself, am I right in thinking I should lay my fire bricks flat if I want a quicker warm up for cooking pizza?
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Post by baileyhsi on Aug 11, 2013 22:27:25 GMT
Right then, Base is now complete (photos to follow when im in front of my pc tmorrow) and just ordering my firebricks and designing the vault. Just a few questions if anybody has any advice?... - can you really get away with clay bricks for the vault roof? - roughly what weight of fire cement am I likely to go through? I've read 75 bricks = 25kg roughly? - any problem with internal dimensions of 100cm in length, 44cm in height, 61cm in width? then entrance 34cm in length, 30cm in height, 56 cm in width, flue set in the centre of the entrance? - any advantage of narrowing the opening? Is a shorter entrance essential? Don't forget I've switched allegiance to the barrel shaped design for simplicities sake Cheers
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Post by cannyfradock on Aug 14, 2013 20:57:27 GMT
Right then, Base is now complete (photos to follow when im in front of my pc tmorrow) and just ordering my firebricks and designing the vault. Just a few questions if anybody has any advice?... - can you really get away with clay bricks for the vault roof? - roughly what weight of fire cement am I likely to go through? I've read 75 bricks = 25kg roughly? - any problem with internal dimensions of 100cm in length, 44cm in height, 61cm in width? then entrance 34cm in length, 30cm in height, 56 cm in width, flue set in the centre of the entrance? - any advantage of narrowing the opening? Is a shorter entrance essential? Don't forget I've switched allegiance to the barrel shaped design for simplicities sake Cheers Bailey If you are going for clay bricks then choose a really dense or high quality clay brick. Old Victorian reclaimed reds are good....or new SOLID Staffordshire blues... or engineering bricks. Fire-cement can only be used to a maximum of 5mm ...otherwise it won't set. Wedge shaped or "trapazoid" cut bricks can be built with fire-cement. If you have mortar gaps...or "perps" larger than 5mm you have to use a refractory mortar. We use the "homebrew" mortar mix of sand, hydrated lime, cement and powdered fire-clay at a ratio of 6:1:1:1. If you can't get hold of powdered fire-clay then try to include hydrated lime (available at builders merchants or garden centers) . I am not experienced with a barrel type build but I believe the general specs apply.....dome height = half the diameter (or width in your case) the length can vary depending on how many loaves you want to bake in one batch. Your internal arch or opening should be in the ball park of 63% of your internal height. The width of the entrance is a question of debate but shouldn't be more than 70% of the width. The entrance arch is up to you. It has 2 main functions.........firstly it is built slightly larger than the internal entrance which creates a rebate for a door (essential in a Barrel/Vault oven as these ovens are mainly built for bread baking )...although they can be used as any other oven. The second function is to create a vent for the chimney within the entrance arch. If you get the % height of the internal opening correct and the vent is OUTSIDE the chamber, this will allow you to get the maximum efficiency out of your oven. Terry
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Post by baileyhsi on Aug 15, 2013 9:09:57 GMT
Thanks so much Terry! I can work on all those points no problem, just one question if I can't get the powdered fire clay (I think I can) then is at simple as just doubling the hydrated lime ratio?
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Post by minesamojito on Aug 15, 2013 10:43:47 GMT
Bailey, looking forward to seeing your first pizza would have to be a good gobble pizza? Terry is the right man to answer these questions as my build was slightly different, maybe one day I'll rebuild and go down the brick barrel route. Cheers Marcus
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Post by cannyfradock on Aug 15, 2013 13:54:08 GMT
Bailey
I've always managed to get powdered fire-clay on my builds so in all honesty I don't know the exact ratio of just sand, cement and lime. Taking into account that the cement and lime are the setting agents for the homebrew and the powdered fire-clay just adds to the thermal value, If I had to guess, I wouldn't double up on the lime. I would just use a ratio of 6:1:1. (The americans tend to use a ratio of 4:1:1:1 for their homebrew, but I think this is too rich for our fine sand so I use 6:1:1:1 to compensate)
Terry
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