Dome/Door height ratio with

[Khelifarami]

Re: Dome/Door height ratio with

Hi, I'm starting a 63" pizza oven and I'm wondering what will be the right height to cook exclusively pizza?
Thanks

[david s]

Re: Dome/Door height ratio with

http://pottery.about.com/od/temperat...p/tempclay.htm

This is the appropriate page to read on the link.

[dmun]

Re: Dome/Door height ratio with

My art ceramics background leads me to use the looser definition of being fired high enough to be insoluble in water

I've been requested to point out the clay isn't water soluble, in the way that sugar is. It will turn into a mud puddle in the presence of water, but not dissolve.

An explanation:

http://pottery.about.com/od/temperat...p/tempclay.htm

Thanks, David.

[david s]

Re: Dome/Door height ratio with

Next time you take a pee you may notice "vitrified China" on the toilet bowl. This is specified so the clay body is impervious, thus reducing the ability for little germies to harbour in the material.

[david s]

Re: Dome/Door height ratio with

No that is known as quartz inversion and occurs at a much lower temp (537 C) Vitrification is the silica in the clay body beginning to melt in company with fluxes like iron and lime, to render the clay body impervious to water, like impervious china toilet bowls, stoneware or porcelain.

[dmun]

Re: Dome/Door height ratio with

If the firebrick were fully vitrified it would be impervious to water, which they are not

We've had the "vitrified" discussion before. In a technical sense ceramics are vitrified if they are fired hot enough to be rendered glass-like and impervious to water. My art ceramics background leads me to use the looser definition of being fired high enough to be insoluble in water, what potters refer to as "bisque" ware, as opposed to "green" ware.

[Tscarborough]

Re: Dome/Door height ratio with

"If the firebrick were fully vitrified it would be impervious to water, which they are not."

Brick that are highly vitrified, such as Endicott brick still absorb water, although it is low compared to most.

[Lburou]

Re: Dome/Door height ratio with

OK, so is that flue area or flue diameter? I have a 8.5" door height (exactly 63% of the 13.5" dome height) but with a 17" width (to accommodate our 16" pizzas) equals almost exactly one square foot of door area (144.5"). With my 6" duratech s/s flue I have 18+" of flue area. So I'm ok?

I think you should be golden with those numbers

[brickie in oz]

Re: Dome/Door height ratio with

a broken brick that has been too quickly burnt, though pale on the surface, presents a darker central patch and con-centric rings of various shades of colour, due mainly to the different states of oxidation of the iron, and partly to the presence of unconsumed carbonaceous matter

Hmmm interesting, there are some bricks we lay as you describe and when cut with a brick saw actually smell like sewerage too.

[david s]

Re: Dome/Door height ratio with

Firebrick are still partially vitrified, cut one in half and you can see the depth of the process. For our application I don't think it is critical other than for appearances, because the cut end will certainly look different.

Here is a firebrick I just broke open. I had to adjust the contrast so you could easily see the difference.

If the firebrick were fully vitrified it would be impervious to water, which they are not.
A properly fired brick, uniform in colour throughout its mass, can only be obtained by slow progressive firing; a broken brick that has been too quickly burnt, though pale on the surface, presents a darker central patch and con-centric rings of various shades of colour, due mainly to the different states of oxidation of the iron, and partly to the presence of unconsumed carbonaceous matter; but the chemistry of this colour-variegation is not clearly under-stood. All Australian soils are high in iron content and this probably explains partly why firebricks are so expensive here.

[perks1018]

Re: Dome/Door height ratio with

Exactly, Lwood. The larger the oven, the greater the amount of "slop" available. In a small oven, you will be limited by the height of the door in relation to the dome, but the width only comes into play when figuring out the flue size needed. Roughly 10% of the area of the door opening is what your flue should be, and a little more is better.

OK, so is that flue area or flue diameter? I have a 8.5" door height (exactly 63% of the 13.5" dome height) but with a 17" width (to accommodate our 16" pizzas) equals almost exactly one square foot of door area (144.5"). With my 6" duratech s/s flue I have 18+" of flue area. So I'm ok?

[Lburou]

Final decision

I wanted to have closure in this thread in case a new person ever reads it....This is what we did:



We decided on a hemispherical dome. In the process, we elevated the height of the dome by two inches, allowing a taller door height for that Ferrel hog and a big turkey -not to mention that the higher the door opening, the greater penetration of light.

We raised the bottom of the dome gage two inches (as shown above) by anchoring the center brick (with the dome tool attached) in its permanent position and shimming it with a scrap of wood (and, the caster anchoring the dome gage raised the center point too). Take the brick out, remove the wood shim and place a new brick in the center and you have it all done.

You also see my version of Hendo's dome gage, it cost <$5.00 at Harbor freight. At some point, the dome gage won't be useful to you, you'll neet to support the chains with sticks, a pilates ball, or other means.

I made a one meter oven floor (39 1/4 inches). My final dome height was 21 5/8 inches (55 cm). That allows a door height of 13 3/4 inches (35 cm), which complies with the 63% rule. I chose the narrower door width of 18 3/4 inches (47.75 cm). (Note: the math is a lot easier in centimeters).

Thanks for all the input everyone.

P.S. Yes, I see the bond in some of my chains is not optimum. With a 'do-over' I'd not use a soldier course and have a lot better bond spacing :-/

[Lburou]

Re: Dome/Door height ratio with

Thanks for all your kind replies!

Since it doesn't matter, I may decide depending on my mood when the time comes....I will cut/break a few bricks and see what they look like, it may have a bearing on my mood at the time.

You guys rock

[Tscarborough]

Re: Dome/Door height ratio with

It is subtle, but yours are probably higher silica and lower fired.

[C5dad]

Re: Dome/Door height ratio with

That is weird - my firebrick is the same all the way through. Looks like companies are firing them differently now than in the past (Mine are circa 1911).

CW