#11  
Old 10-09-2006, 08:42 PM
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I cut my bricks to make sure they were tight side to side, but did not cut them for a taper top to bottom. If they are tapered in both dimensions you want the short dimension inside (even if only tapered in one dimension the short side goes in). Tapering side to side makes sure the whole ring is locked. Tapering top to bottom just means you do not need to think about the angle of the joint and further minimizes mortar reducing the chance of the joints failing.

I don't think soldiers are necessary - I would bet they have designed these bricks to make a complete 39" arch - do they specify the dome height? Soldiers would raise the entire height of the dome. I would probably stay with the plans of the kit they are selling. It would be possible to make the oven less stable if you raise the dome on soldiers (although not really likely). I have a low dome (42" wide and 18" high) brick oven and have no problems using it for pizza and bread.

I think you are fortunate to have a cut brick option - still get to do it yourself but have the comfort of an engineered brick dome with tight joints.
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  #12  
Old 10-10-2006, 01:27 AM
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Default taper etc.

Hello Maver,

thanks for your comments. I'll have to ring the supplier tomorrow to see which way the taper goes - I'm sure they would have mentioned it if the bricks were tapered both ways...

Trouble is, they do NOT rpt NOT have any plans or instructions: the supervisor who developed this 'full cut dome' kit has since retired (and is living in the U.S., I'm told!), so you get a load of bricks and mortar and tiles, and you're on your own :-)

That's why I keep asking these dumb questions. You're probably right about leaving out the solder course - the kit deos NOT mention straight bricks, only arch bricks, most of them with the flatter taper, about a third with the deeper taper.

IF they taper along the 230 mm length (sorry, can't do imperial units offhand), that would mean the oven wall would be TWICE as thick as the 4.5in suggested elsewhere on your forum! That would produce too much thermal mass, I'd have thought... So I hope they taper across the 115 mm width, which would mean they will be laid in 4.5in wide courses. This also seems to account for the low number of actual bricks in the kit (63 of the flat taper, 33 of the steeper taper, plus some extras I've asked for). But perhaps I shall be told otherwise tomorrow by the supplier...

The quote I received also includes 2 sheets of Calsil for insulation under the 50 mm thick floor tiles, which are 230 x 230 mm each.

There is NO mention of how the opening would be set out - perhaps one just leaves out a certain number of blocks each course? Another question to my patient Darley interlocutor, Tonia Taylor...

I've been stuffing around with an old IntelliCAD program trying to creat virtual blocks of the dimensions listed, and then assembling them into a virtual dome - but tonight I've gone back to pen and paper :-)

Cheers!

Last edited by carioca; 10-11-2006 at 02:35 AM. Reason: typos, sorry
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  #13  
Old 10-10-2006, 07:26 AM
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Default tapering

OK, I was lazy and did not give that full attention. These sound like they are essentially full sized fire bricks tapered on the shortest (vertical) dimension - I bet you are right that it is along the 115mm width they are tapered. I'm a little surprised that the more aggressive taper (to 57mm) constitutes the lesser of the bricks. When I built my 42" low dome oven I had the taper going from more aggressive to less, so I used more bricks with aggressive angle to them (angle created by wood shims rather than pretapered bricks), although I started with 1/2 brick soldiers. With the way yours are tapered a split brick would make a fine soldier, probably with the 75mm on the inside.

You could assemble your oven with full size bricks but the 230mm length split in half would give you a rounder oven. You could then taper the upper rings yourself into trapezoids (no need on the lower 4 rings) to maintain a narrow vertical joint between the bricks. You can see this starting at row 5 of my oven dome picture here:

http://www.fornobravo.com/forum/atta...achmentid=1141

You can see that I tapered every other brick initially (to minimize cuts) until they were too close together, then tapered every one.

I think the vertical tapering is convenient and can ensure you end up with the proper dome profile but that making tight vertical seams (side to side) creates dome strength - but I'm no engineer. That's just a feel thing based on observations during my dome construction.
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Old 10-10-2006, 04:29 PM
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Default taper reviewed...

Hello Maver,

Thanks for your feedback, I'll definitely study your oven.

Meanwhile I just talked to a person at Darley Refractories. She confirmed that there is NO rpt NO written material covering the 'kit' which apparently was put together by a retired supervisor.

BUT: the taper runs across rpt across the width of the brick, i.e. one side of 230 mm is 75 mm high, the opposite side is 63 mm!

AND: the people who buy this stack of materials for a 'full cut dome' oven cut the 230 mm long brick in half to construct the arch - except for the first course, that uses the whole (but tapered) brick.

She said 90 per cent of the people who buy refractory bricks from the company to build ovens build DOMES!

Bye for now (I've got another attempt to coax our 13-y-o electric oven back to life before my wife blows her stack! We've been eating supermarket 'bread' for three weeks now...),

Carioca
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  #15  
Old 10-10-2006, 09:17 PM
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so the taper appears designed to help with creating tight seams in the vertical arch. I think it makes sense that the average oven maker would split the bricks in half. Making the cuts to form trapezoids is not much harder. I believe I used a 15 degree tilt to the skil saw. For the bricks near the top of the dome I tapered them both top to bottom and in to out.
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  #16  
Old 10-11-2006, 12:23 AM
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Default pregnant pause...

Hello Maver,

tks for ur reply. I've now decided, in view of the $A1500 quote - a third of it freight - to save up for a few months while I tackle the foundation...

At least I know WHERE I'll build (once I've figured out the details of post&beam footings:-)) Attached is a view of the 'virgin' site...

Cheers for now (I still have to look at your oven details but first I must bait a cat trap and then cook dinner for Bianca, my mate for the past 40-odd years - who also helped build and render the 'house' and 'shed'),

Carioca
Attached Thumbnails
several dumb questions, if I may...-img_0513.jpg  
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  #17  
Old 10-11-2006, 05:20 PM
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Default mag plans for a tunnel oven

Hello there,

my potential supplier of refractory bricks kindly sent me a magazine article (.pdf) that explains in very good detail how to build a tunnel-shaped oven...

I suppose that - mutatis mutandi - one can adapt the techniques to a circular dome oven (for which my supplier does NOT provide any instructions).

Anyway, I'll try posting the PDF file as an attachment.

TOO large by far!!!

Interested parties pls e-mail me direct for the 600KB file, sorry.

Cheers,

Carioca
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  #18  
Old 10-11-2006, 05:51 PM
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are the tunnel oven directions specific to the tapered bricks your vendor supplies? If they are, you could look at how they are laid out (how many for the arch and where they are placed) to develop an idea how that taper would apply to a dome.
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  #19  
Old 10-12-2006, 11:09 PM
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Yes Maver, they are using the tapered bricks from the supplier, after initially laying two courses of straight, i.e. non-tapered bricks...

I'll work it all out, in the end - perhaps by using a big beachball for support while arranging the bricks in a dome without any mortar to try it out :-)

Tks again, Carioca
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  #20  
Old 10-13-2006, 08:55 AM
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skip the beachball, just form an arc with the bricks laying on their side on a flat surface. This will show you how the vertical joints will fit. If you are using real bricks (or models with the brick's dimensions) allow a small gap for the mortar. Again, the profile of the tunnel oven could translate into the dome profile (a dome is an arch spun on the central vertical axis ), so you could use the plans of the tunnel oven engineers to determine how to lay out your dome. If it's a high arch and you want a lower dome, skip one or two courses of straight bricks.
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