cec
WFO Team Player
Posts: 160
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Post by cec on Apr 14, 2012 11:08:31 GMT
I will be doing the dome freehand and I'm going to do the same as you did on 1 of your builds , with some drain pipe in the center and some forms going round to form the arch .
What would the mix be for fondue cement , ie 2 / 1 , 3 / 1
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 14, 2012 15:40:20 GMT
had to start a bit today , i need to get 2 supporting walls up see pic Attachments:
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 14, 2012 15:43:04 GMT
but it started to rain so i had to make a heath robinson teepee , it did the job , now iv got the wall finnished i can start getting the base ready , the weather is ment to be ok tomorow so fingers crossed i can get done Attachments:
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 14, 2012 15:43:45 GMT
another pic Attachments:
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 15, 2012 11:57:51 GMT
2 questions
1 , am I right in thinking the height of my dome is half the diameter of the base plus thickness of fire buck floor ? .ie base is 1000 mm so 500 plus 50mm brick ?.
2 , do I leave a mortar joint on the inside or just butt them up ?
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Post by cannyfradock on Apr 15, 2012 12:46:22 GMT
Cec Just to uncomplicate my previous posts. Dome's are normally built using a form (like mine) or built free-hand, using a swivel type jig ...  (Charlie's build)... picasaweb.google.com/115426447285405371194/WoodFiredOven...to hold 1 brick in place before moving the jig and laying the next brick (some people lay 3/4 of the dome purely by hand until the brick and mortar "grab" or set (10/20 seconds)). Free-form uses the same Home-brew, 3:1:1:1 sand, lime, fire-clay and cement (opc).......except replace the ordinary (opc) cement with fondue.....or go 50/50 opc and fondue. Q 1......Yes. The internal dome height is half the diameter. (from finished cooking hearth to uppermost internal height. Once you know the internal height (50cm) you can work out the height of the entrance arch. = 63% of internal height = 315mm. Q 2....Unless you cut perfect trapazoid (angled) cuts, you will find it difficult to dry but the internal edge of the dome bricks. The gaps will become greater the further up the dome you go. Just try to keep the edges as close as poss. As long as you use the homebrew mix, it wont matter how large these gaps get. Terry |
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Post by turkey on Apr 15, 2012 13:36:10 GMT
using the swivel jig is easy for lower layers, I think for the upper layers can become a lot harder. Some folks use wood offcuts to support a set brick releasing the jig for the next brick.
another idea I have seen is once you get to the extreme angles get a yoga ball in the oven and inflate it some it fills the top hole as a form and use that for support when closing up. The only issue with a form is you cannot control the mortar on the inside of the oven, I think our perfectionist cousins over the pond frown on this and go for a full jig build.
I think I will jig and try to find a cheap ball / support for the last few rings.
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 15, 2012 17:46:21 GMT
I'm going to use a jig , the same as you used terry , tube in the middle and some bored going round ,
What is OPC ? Am I just been thick , I dont know what you mean by 50/50 OPC / fondue ,
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 15, 2012 19:25:28 GMT
imageshack.us/photo/my-images/543/soven6012.jpg/In pic is that opening the 63% it needs to be , I'm guessing inside measurements , And does the porch have to be 63% as well , oh and length of porch ? Oh sorry for all these stupid questions , but I'm like a sponge when I take on something new , I'm the same with everything
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Post by Terry Hardwood on Apr 16, 2012 8:50:17 GMT
What is OPC ? Am I just been thick , I dont know what you mean by 50/50 OPC / fondue , No, you are not thick friend. Sometimes 'experts' use technical terms instead of uncomplicated practical advice. OPC is Ordinary Portland Cement, or just Portland for short. But I have no idea why you would put melted cheese in a mortar mix.  |
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 16, 2012 17:08:15 GMT
But I have no idea why you would put melted cheese in a mortar mix. [/quote] ;D cement fondue  Iv just got my powdered clay and some very nice firebricks for a song , 12" x 4 1/2" x 3" for a 1 quid each  2 x clay £20 . So Iv now laided the base 2" x 2' x 3' slabs with thermolights on top . Total cost so far £45  I just need to get sum lime then Iv ready to start the dome . Oh just to add the place had 3 pallets full of theses bricks , so if anyone lives near Scunthorpe this is the place to go , the chap even said he would cast me a harth for £70 .he was so helpfull , It's called Trent refactorys Just to ask yet another question , do I use normal mortar or the home brew to fix the fire bricks Cheers |
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Post by turkey on Apr 16, 2012 17:16:06 GMT
to fix the initial layer of firebricks that will be the hearth you usually use a 1:1 mix of sand and fireclay .
then for the dome structure you would use homebrew.
also for your comment above on the oven hight, most folk lay the floor and extend under the dome, so the hight of the dome is simply the radius. However if you read my build diary you will see I am the last person to give advice here lol.
opc I expect is ordinary Portland cement.
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 16, 2012 17:24:02 GMT
to fix the initial layer of firebricks that will be the hearth you usually use a 1:1 mix of sand and fireclay . Not wet , if it's dry does it not make it hard to level it off ? . Is you diary on the old forum ? |
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Post by tonyb on Apr 17, 2012 10:56:18 GMT
Some use wet and some dry. Me,I used wet.
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cec
WFO Team Player
Posts: 160
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Post by cec on Apr 17, 2012 16:18:25 GMT
I think I will use it wet , I think it will make it easyer to level
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