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Post by spider44 on Jul 8, 2015 19:36:59 GMT
I am sorry Phil my reply did not post correctly I have replied again (PM) and apologise my message did not get through to you to explain what happened. The message should be there now please let me know if you don't receive it.
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Post by spider44 on Jul 8, 2015 19:51:50 GMT
I received the order from Kilnlinings today and started experimenting with the layout. I think a 40" diameter oven seems to sit nicely in the space available and leaves enough room for a reclaimed brick finish on nthe dome after the insulation layers. On the Forno Bravo plans they suggest an opening of between 19" and 20" for a 36" and a 42" oven respectively. My opening in the picture would only be 17.5" on the oven side but seems plenty big enough and allows a a landing about 18" wide or two bricks wide. I could easily increase the entrance size but not sure if it is needed? (Post script - this approach was subsequently not adopted and I have changed to using Half-Soldiers for the first ring see later posts but I'm keeping it here to help document my thinking and how it changes as I go along).
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Post by cobblerdave on Jul 8, 2015 21:42:15 GMT
G'day The width of the opening is determined by where the top of the opening meets the ever decreasing size of the dome. Put it to far forward and the opening width to small and the dome will turn out a teardrop shape. So it's inportant to have a side section to help you make sure the opening supports the underside of the dome. This then determines the width of the opening. It usually turns out roughly 1/2 the width of the oven size Regards Dave
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Post by spider44 on Jul 8, 2015 23:05:35 GMT
G'day The width of the opening is determined by where the top of the opening meets the ever decreasing size of the dome. Put it to far forward and the opening width to small and the dome will turn out a teardrop shape. Thanks Dave - your advice is very welcome. I didn't think of this! I know that the height of the opening should be 63% of the height of the oven. I'm aiming for an oven height of 20" for a diameter of 40". So the opening height should be 12.5" and now it makes sense that this will determine the width - Thank you!So it's inportant to have a side section to help you make sure the opening supports the underside of the dome. This then determines the width of the opening. It usually turns out roughly 1/2 the width of the oven sizeRegards Dave Not quite sure what you mean by a side section? Any chance you could elaborate? Thanks Patrick
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Post by spider44 on Jul 9, 2015 10:48:09 GMT
Have done a layout of the dome itself and getting a diameter around 40.5" and a height of 20.5" with the bricks as shown. I used my tile saw to cut a notch in one side then the bolster to half the bricks which worked really well. I experimented with the layout and feel happier without using a soldier * course. ( *Note that this shows a cross section of the intended dome without a soldier course and laying on the hearth directly. I subsequently changed this to include a half-brick soldier course separate from the hearth). I was able to lower the dome height to 18.5" and increase the diameter of the oven to 41" including a gap for expansion).
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Post by spider44 on Jul 9, 2015 11:20:20 GMT
Decided to experiment again with half soldiers for the first course and that works better I think. Now getting a lower dome height of 19" for a diameter of 41" and now the hearth sits inside the ring of soldiers rather than on top which is the other combination I have not tried. Decisions, Decisions!
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Post by cobblerdave on Jul 9, 2015 13:00:49 GMT
G'day Patrick Had a long shift today and had no chance to reply so it's a pleasant suprise to find that you'd done some research of your own. I'm a bit visual like you and once I " see it " I can understand it better. Just to throw another spanner in the works so to speak. The shape of the oven opening the mouth has a big bearing on how it fits. It can be square like mine( least prefered option trust me the angles are mind blowing). 1/2 round least easy to fit items through. Flattened arch shape, better access than the 1/2 round. And the straight sided with the flat arch in top like phils, which is probably the best option if your using a soldier course as it ties in better Regards dave
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Post by spider44 on Jul 9, 2015 16:34:38 GMT
Thois shows the state of play with the layout for the dome on what appears to be becoming a 41" Pompeii with a 18.5" high dome. I'm really enjoyed playing about with the bricks and experimenting with different approaches. I've laid first chain on top of what is in effect a cross section of my intended dome. I've included a bit of cardboard to show the small gap between the heart and the first soldier course. I've done the same with the entrance to the arch but am not happy with the shape yet and am going to play around. I'm getting 18.5" wide and about 11.5" high using a half-soldier course like on the dome itself. It is a failry small opening but fits in with the 63% rule quite well and exceeds the minimum recommended on the FB plans.
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Post by spider44 on Jul 15, 2015 17:24:02 GMT
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Post by chrisb on Jul 16, 2015 16:21:11 GMT
Hi Guys, quick question, I am following the same sort od design as above. What should my plinth thickness be? I am unsure to go with 3" or 4". Thanks
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phi1
valid member
Posts: 91
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Post by phi1 on Jul 16, 2015 16:34:00 GMT
Hi Guys, quick question, I am following the same sort od design as above. What should my plinth thickness be? I am unsure to go with 3" or 4". Thanks Chris I cast mine to 4 inches with rebar to strengthen it
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Post by chrisb on Jul 16, 2015 16:44:45 GMT
Yer I thought that would be the thickness, many thanks, 4" and 10mm rebar it is!
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Post by spider44 on Jul 20, 2015 21:35:40 GMT
Have hit a snag and wondered what others have found works? The mortar mixes I have tried to bed the fire bricks down on seem to go stiff very quickly even if wet. I'm finding it nigh on impossible to create a notched surface as suggested. I've tried with and without fireclay as follows.
Mix 1 - 6:1:1:1 Standard Homebrew with sharp Sand, Lime, Fireclay and portland cement.
Mix 2 - 4.1.1 Omitting the fireclay and applied.
Before the second mix I applied some oil to the surface of the fibreboard to help reduce it drying out the mortar without any noticeable difference.
I've now removed both mortars and having another think.
What about laying it on a dry mix I think I read that somewhere but what mixc would you recommend?
Thanks in advance.
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Post by oblertone on Jul 21, 2015 8:36:39 GMT
No personal experience but reading build threads it would appear that a dry sand bed is favourite; achieves a level surface yet allows removal of a stone/tile that becomes damaged in use. I cheated and used vermiculite board for a level base.
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