Dome/Door height ratio with

[GianniFocaccia]

Re: Dome/Door height ratio with

I don't think it is critical, whichever way you go.

[Tscarborough]

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.

[GianniFocaccia]

Re: Dome/Door height ratio with

Thanks for the clarification, David. I seem to remember dmun stating that a brick's ability to withstand heat is greatest where the firing process was most effective. I guess there is a more accurate term for this surface property. Maybe TS would know.

[Lburou]

Re: Dome/Door height ratio with

That solves the issues for sure, I think I'll do that too....A very clean build! Thanks for the picture

I'm using used firebrick for the dome. I've read a couple posts where there was a recommendation as to where to put the cut side of the firebrick relative to the center of the dome. In my case, the cut side is likely to be the cleanest surface and best surviving edges....Why not put the cut surfaces toward the inside of the dome?

I went with the cut side in because I thought it looked the cleanest but now wish I'd put it facing out.
The way I understand it, as bricks originally fire, the outside surface of the brick is the most exposed to the firing heat and is the most vitrified.

I dont think fire bricks will be vitrified?

Modern house bricks are vitrified and are way harder and lots more brittle that fire bricks.

Vitrification is when the material actually begins to melt. Fire bricks are designed not to vitrify even at very high temps like 1500 C This means that there is no vitrification either on the surface or in the middle, it also means that a fire brick is really porous and therefore has a tendency to soak up moisture like a sponge.

So, what is the consensus here, cut face 'IN' or 'OUT'?
I'm flexible on this, just want to understand enough to have a reason whichever way I go.

[david s]

Re: Dome/Door height ratio with

Vitrification is when the material actually begins to melt. Fire bricks are designed not to vitrify even at very high temps like 1500 C This means that there is no vitrification either on the surface or in the middle, it also means that a fire brick is really porous and therefore has a tendency to soak up moisture like a sponge.

[brickie in oz]

Re: Dome/Door height ratio with

I dont think fire bricks will be vitrified?

Modern house bricks are vitrified and are way harder and lots more brittle that fire bricks.

[GianniFocaccia]

Re: Dome/Door height ratio with

Why not put the cut surfaces toward the inside of the dome?

I went with the cut side in because I thought it looked the cleanest but now wish I'd put it facing out. The way I understand it, as bricks originally fire, the outside surface of the brick is the most exposed to the firing heat and is the most vitrified.

[Lburou]

Re: Dome/Door height ratio with

I am not sure what a cantilevered dome is, but I did find an interesting construction method by a commercial oven manufacturer in Italy via their website. After constructing a very shallow brick dome, they lifted the entire mass via a crane and lowered it onto tall vertical soldiers. The perimeter edges matched up perfectly and appeared to place all of the thrust downward through the middle of the soldiers.



I copied Les and made the first two horizontal courses vertical prior angling the third course inwards.

John

That solves the issues for sure, I think I'll do that too....A very clean build! Thanks for the picture

I'm using used firebrick for the dome. I've read a couple posts where there was a recommendation as to where to put the cut side of the firebrick relative to the center of the dome. In my case, the cut side is likely to be the cleanest surface and best surviving edges....Why not put the cut surfaces toward the inside of the dome?

[GianniFocaccia]

Re: Dome/Door height ratio with

Without buttressing or the tension cable method, I think a low dome oven could possibly have structural issues placed upon the soldier course. If you choose not to use one of those two methods, I would consider cutting the soldier course nearly in half with a catliever angled top to get that dome into its turning as soon as possibly.

I am not sure what a cantilevered dome is, but I did find an interesting construction method by a commercial oven manufacturer in Italy via their website. After constructing a very shallow brick dome, they lifted the entire mass via a crane and lowered it onto tall vertical soldiers. The perimeter edges matched up perfectly and appeared to place all of the thrust downward through the middle of the soldiers.

The best solution seems to be Dmuns idea of removing the soldier course and simply using the same 1/2 cut bricks set horizontally just like the rest of the dome. You will lose a bit of height towards the outside walls, but considerable less stress on the side bricks and mortar

I copied Les and made the first two horizontal courses vertical prior to angling the third course inwards.

John

[shuboyje]

Re: Dome/Door height ratio with

I agree with everyone else that you certainly want to "buttress" the soldier course if it is going to be of significant height. I personally think stainless cable with all stainless hardware and angle iron to bridge the door is the easiest way for most people to go due to ease of both getting the materials and using them.

[stonylake]

Re: Dome/Door height ratio with

i have a 36" and as giannifoccaccia mentions earlier in the thread, the dome just ended up a couple of inches taller than i had planned. i built on a full soldier course with a cut taper 12" high door and a 21" dome, so the opening ratio is 57%. i had the gang over on NYEve, and we made 15 or 20 pizza's. i have a slight problem with smoke coming out of the doorway, it discolors my exterior arch tile, but i think (as Dino told me) that my chimney needs to be a bit higher. i'm currently at 24", and my oven is somewhat sunken in my back yard.

[lwood]

Re: Dome/Door height ratio with

I have a 60" low dome with the soldier course and no structural problems. The insulation layer seems to hold things together.

[brickie in oz]

Re: Dome/Door height ratio with

with a catliever angled top

OK youve lost me, what is it?

[RTflorida]

Re: Dome/Door height ratio with

Without buttressing or the tension cable method, I think a low dome oven could possibly have structural issues placed upon the soldier course. If you choose not to use one of those two methods, I would consider cutting the soldier course nearly in half with a catliever angled top to get that dome into its turning as soon as possibly.
The best solution seems to be Dmuns idea of removing the soldier course and simply using the same 1/2 cut bricks set horizontally just like the rest of the dome. You will lose a bit of height towards the outside walls, but considerable less stress on the side bricks and mortar

RT

[Lburou]

Re: Dome/Door height ratio with

No worries. Worst case scenario your oven collapses and you have to start over, so if you are confident with your design, my advice is to go for it.

That is a show stopper! I've seen several people do the soldier course, I guess they don't show the dome falling down

Thanks

Lburou,
For what it's worth, my oven dimensions are almost identical to what you are planning. After difficulty getting my soldiers to mortar together properly in 100F heat, I switched them out to horizontal courses. I feel better about eliminating the outward thrust the dome places on soldiers (thank you dmun and TS) and feel my dome is structurally more solid.
John

Thank you John, I'll look around for any pictures you have posted on this site, maybe that will clear my thinking

Leeb