How big should my dome be????

[cynon767]

Maybe I'm missing something, but I'm not sure I can see the advantage of a round-cornered square dome. It seems to me that you'd only be gaining a little extra floorspace for a lot of extra fancy brickwork squinching in the corners, and ending up with something that may not be quite as strong structurally. I'm not an engineer or an architect, but I've always been under the impression that the reason a barrel vault requires more reinforcement is the fact that the outward thrust is perpendicular to the wall; wouldn't a squared dome have many of the same problems?

[hulkiebear]

The design I am playing with at the moment, is basically a circular dome, split into 4 quarters, expanded out enough to fit an arch each way. As my slab is constructed and I am tight for space, gaining a couple of inchs is really important, and as the arch in between each quarter section can be constructed first and is a straight forward arch with no cutting, this will actually mean less fancy cuts! Also, I can construct each corner one at a time.

The barrel oven needs so much support because it has a shallow arch which pushs out, as the arch in my dome is still as good as a half circle, it will need alot less support, but this is not an issue, I will tie in a concrete sleeper at either end of the arch into the slab to prevent any outward force.

[Rastys]

It sound like you have it all sorted and now know where you are heading! Great stuff hulkiebear, go for it. I'll be keen to follow your progress.
A lot of people seem to believe that a perfectly symmetrical/spherical dome is going to reflect the heat back down to the floor like a lens manipulates light.
I have a different theory that the dome is merely a heat 'sponge' to absorb and then to emit heat within the oven to providing the cooked item with radiated heat from above rather than just from below (the hearth).
A round cornered square oven will give the biggest and most economical floor space that is available but not necessarily built with almost vertical walls and "squinched" as cynon767 suggests. Select maybe a 32" oven plan and put a couple of extra bricks in the width and length to fit you base.

[hulkiebear]

Thanks for the encouraging words Rasty, I have started a post in the Getting Started section, showing my progress on this project! I won't be explaning absolutely everything I do, so as not to bore anyone who reads it, as you guys are my only remaining audience that will take any interest(wife seems to be a bit bored of me talking about it!). But will be glad to answer any questions in detail!

I agree about the heat sponge thing too Rasty, I don't see how the dome can focus heat on one point, unless the food is in the very centre. Also, as there may not be a fire all of the time, heat will not be reflected from one point to another point, but will simply radiate from the dome, so I don't think my design will cause much difference from a true round dome,

I have starte with a 26" dome design, split the four corners and added an extra 8" in between. I think this will give me a similar oven floor area and volume to a 36", but will give me precious 2" to spare!

It may all work, but, we will see, interesting to say the least!

[cynon767]

Thanks for explaining that...I wasn't seeing it at first. It sounds like it will be very interesting... can't wait to see pics!

Although, I have to admit, it's still easier for me to visualize thinking of a 36" dome with the sides cut off... is that still incorrect?

[hulkiebear]

It's not quite a 36" dome with the sides cut off, but, for all intensive measurements, that is a close enough analagy. As you pointed out, if I just cut sides off, I will end up with all sorts of problems and tricky cuts to do.

If you can imagine that I build a single arch, (180 degrees) into directions(froming a cross from above) then fill the corners in with perfect quarter domes, thus still gaining the strength that a dome prevides.