Soldier on

[gregarious]

OK, newbie question regarding the dome shape and height. I have searched for this information and admit I may have just missed it.

I am building a 42 inch high-vault pompeii oven, and had anticipated an inside height of 21 inches (i.e. a hemisphere). I am debating weather to place the dome on the floor or around it. If I place it ON the floor, won't or shouldn't my oven height then be 21 inches PLUS the height of the soldier/first level? Or do people generally tilt the subsequent courses in such a way that the final height reaches 21 inches and the post-soldier level curve is a little steeper? I suspect the answer is the latter (curve the dome in to make the final height after the first level) but I would really love to hear from those of you who have placed the oven ON the floor-what did you do?! I am starting on the dome this coming weekend and would really appreciate the forum's insight.

[gdest]

Re: Soldier on

It shouldn't matter either way. It all depends upon the height of your first row. If you get the plans from the forno bravo site, this is explained. By the way the plans are free.

I too am planing on a 42" oven and what I am debating is if I want to add all the brick cutting to my plans if I put the floor on the inside of the dome or stack the dome on top of the floor.

[dmun]

Re: Soldier on

shouldn't my oven height then be 21 inches PLUS the height of the soldier/first level?

No. That would have your dome absurdly high for even a half brick soldier. Most people who use the soldier course angle the bricks on top to get a start on the angle.

For the record, I don't see the point of the soldier course anyway, whether it's on top of the floor or not.

[fxpose]

Re: Soldier on

For the record, I don't see the point of the soldier course anyway, whether it's on top of the floor or not.

I've been wondering about that myself. I plan on starting with half bricks like any other course on top of the oven floor.

[Neil2]

Re: Soldier on

For a 42 inch oven, I recommend a dome height of 85-90% of the radius = 18 1/4 inches or so. You want an elliptical dome, not a hemisphere.

The soldier course gives you a "straight wall" interior corner instead of a sharper angle. This leaves more usable floor area. If building on the hearth, start with a half brick soldier course then "catch up" to the ellipse in the first two or three courses. Something like this:

[gregarious]

Re: Soldier on

I appeciate all of your responses. I also really appreciate the free plans from FB and have read them through several times. The FB plans indicate a true hemisphere if a high vault oven is desired. So in my case it would be 21 inches high (or presumably less if I want) for a 42 inch oven. The use of fiberboard is vaguely discussed in the FB plans. For the first time builder it really doesn't seem like it will support the weight of the dome. I guess I will find out. The only really good diagram of this are the cross sections starting on page 15, and the scale in that diagram is wrong as the dome wall width cannot be as narrow as the diagram would imply, which unfortunately erodes my confidence in what the diagram portrays. If it isnt obvious that I have probably overthought this- it should be now! While there are some amazingly good oven builds outlined here- I ultimately have decided to follow the same architecture as the build by pizza bob- whose meticulous CAD drawings and elegant transition from dome to vent landing I have been pouring over, and recapitulating. His oven appears to be very cleanly laid out and I would love it if detailing like it or something similiar had been included with the Pompeii oven kit (which I did buy!). I will be placing the soldier level, cut at 20 degress inward tilt, around the cooking floor and the whole thing will rest on the supplied 2 inch fiberboard. Anyway thanks all for the great advice, and special thanks to pizza bob for sharing his oven build.

[dmun]

Re: Soldier on

For the first time builder it really doesn't seem like it will support the weight of the dome. I guess I will find out.

The insulation materials have tremendous compressive strength. They build entire HOUSES on top of insulation foam these days.

[jagizzi]

Re: Soldier on

You do realize that there is also a layer of concrete that is supporting the oven as well, right? it is not just the fiber board.

Just thought I would mention this, although I am sure you have seen that bit in the plans.

Jim

[gregarious]

Re: Soldier on

You do realize that there is also a layer of concrete that is supporting the oven as well, right? it is not just the fiber board.

Just thought I would mention this, although I am sure you have seen that bit in the plans.

Jim

On my oven, the base is contructed, the concrete hearth has been poured, the oven floor and fiberboard laid down, the soldier course and entryarches/vent have been completed and the dome completed up to the second course. The remainder of the dome awaits. So, yes...I do know that it rests on concrete. My statement/query about fiberboard was based on a hypothesis: that a soldier course may change the force vector of the dome to more outward than down (especially when the soldier level is cut at an angle, as I did). With a compressive material- like fiber board, IF the outer (free) edge of the fiberboard compresses more than the inner aspect, then the soldier course will have a tendency to bow out and weaken the dome. I probably do not understand the physics/structural engineering here well (maybe not at all), but it seemed like a reasonable question given the nature of fiberboard (ie seems to crumble when cut). IN any event- my die is cast as I am already well underway! Thanks for your responses.