Got these firebricks, how should I build a pizza oven with them?

[Fizz]

Well, I put one I've kept indoors for awhile in the stove , and it looks just about the same after firing yesterday...

Nice and clean... Doesn't smell of forest and moss any more....

Think I'll do it to all of them, in batches...

[Fizz]

Came up with another question, that I couldn't find an answer googling it..

Does anyone know if there's any risk in using my indoor fire place to clean the fire bricks? I have a stove that easily reaches the carbon burn off temperature, and could probably fit three or four bricks at a time... I usually fire it up every day during the winter...

The only issue I could think of is the water content in the bricks, but are there any other unknowns in the equation I'm missing?

[Fizz]

Point taken, if I think about it, even on a dome there is a long seam at each course. So I would do what works for you.

Thanks for your input!

I think I´m going to make use of the fact that the winter is long over here, I´m eager to get started and the kids are away for Christmas, and get some refractory cement and pre-make the arches! If I add a second layer of bricks with refractory mortar on top of the curved firebricks it has to be strong enough. Then a layer of LECA + cement, and then insulation.

[UtahBeehiver]

Point taken, if I think about it, even on a dome there is a long seam at each course. So I would do what works for you.

[Fizz]

Wont' you still have a long joint seam (circular) where each premade arch segment butts up to one another? Here is a pic from Tscar's build showing a staggered bond.

https://community.fornobravo.com/fil...photoid=279192

That's true, I didn't think about that joint... Is it better to have the longer joints lengthwise, as in the pic you linked to?

[UtahBeehiver]

Wont' you still have a long joint seam (circular) where each premade arch segment butts up to one another? Here is a pic from Tscar's build showing a staggered bond.

https://community.fornobravo.com/fil...photoid=279192

[Fizz]

It would be best to stagger the bond on the arch for strength and integrity. By pre-making the arches there will be a long seam at each joint of the pre-made arch unless I am not understanding what you are trying to do.

If I use 4 and a half brick,I can turn every other arch 180 degrees and have staggered joints? I got to learn the slang used, so I´m googling a lot of words now ... If you look at the third pic, of two mock-up arches, that´s a staggered joint, right?

[UtahBeehiver]

It would be best to stagger the bond on the arch for strength and integrity. By pre-making the arches there will be a long seam at each joint of the pre-made arch unless I am not understanding what you are trying to do.

[Fizz]

As far as not using mortar, this is more theoretical than practical. Refractory cement is designed for 1/8 inch joints or less. This cement helps fill in normal gaps that imperfect brick will have when laid together. It also has some glue factor as construction reaches higher up on the dome and the brick want to slide off the chain because of gravity. Refractory cement sets up during the curing fires and really bonds the brick together so you have a very stable unit. You mention curved cuts and this is another challenge as the blades we use are straight. You can't really cut a curve unless it is so gradual as to no be noticeable. You can grind a curve out, but this is challenging as well to get it perfect. Mortar is your friend, not the enemy.

When building a round structure with square brick, you have big joints in certain places and Refractory cement is not appropriate in these places. Refractory mortar can be used to fill in wider joints up to and even exceeding an inch in width. If you use square brick to build a sphere or dome, you will have some joints approaching 1 inch on the outside of the dome. Refractory mortar is different then refractory cement in that it has sand in the mix to give the mortar more substance to fill bigger gaps. It is still temperature stable and very handy when you get tired of making the perfect cut and realize that you are the only one who will ever see the joints on the inner arch where it meets the the wall chains.

Thanks for the input!

It´s winter here in Sweden, which means temperature ranges btw -4 to 40 F .... I´m thinking about starting to make separate arches indoors, to speed up the process when I start building the oven .. Making one "wood template" and using refractory cement to join 4 and a half curved brick to make 8-9 arches instead of building the entire vault on top of a larger template should save me some time ...

Do you think it´s a good idea?

[dakzaag]

As far as not using mortar, this is more theoretical than practical. Refractory cement is designed for 1/8 inch joints or less. This cement helps fill in normal gaps that imperfect brick will have when laid together. It also has some glue factor as construction reaches higher up on the dome and the brick want to slide off the chain because of gravity. Refractory cement sets up during the curing fires and really bonds the brick together so you have a very stable unit. You mention curved cuts and this is another challenge as the blades we use are straight. You can't really cut a curve unless it is so gradual as to no be noticeable. You can grind a curve out, but this is challenging as well to get it perfect. Mortar is your friend, not the enemy.

When building a round structure with square brick, you have big joints in certain places and Refractory cement is not appropriate in these places. Refractory mortar can be used to fill in wider joints up to and even exceeding an inch in width. If you use square brick to build a sphere or dome, you will have some joints approaching 1 inch on the outside of the dome. Refractory mortar is different then refractory cement in that it has sand in the mix to give the mortar more substance to fill bigger gaps. It is still temperature stable and very handy when you get tired of making the perfect cut and realize that you are the only one who will ever see the joints on the inner arch where it meets the the wall chains.

[Fizz]

I dont' know that there is any real advantage to building an oven with no mortar. It's more of a dream some builders have.

Check how the italians do it... https://youtu.be/sM9zteuE8UA

This is the oven that is in every pizzeria in Naples

I think I´ve watched every video available at Youtube (about oven building), except that one ..

Interesting use of metal in the oven, I guess the ring around the dome is pretty good when making the oven in two pieces, but I wonder how they make the door/opening work ..

I noticed that they used LECA to isolate the oven, that answered one of my questions, since vermiculite is somewhat hard to get by here in Sweden .. Precast LECA blocks are a staple when building walls etc. here in northern Europe!

[deejayoh]

I dont' know that there is any real advantage to building an oven with no mortar. It's more of a dream some builders have.

Check how the italians do it... https://youtu.be/sM9zteuE8UA

This is the oven that is in every pizzeria in Naples

[Fizz]

Nothing wrong with using common brick for mass, use refractory mortar since the temp will go up, although I doubt you will get over 550 F in the mass of the oven. Better to be safe. If you corbel the walls, think about cutting the projection of the brick off before you lay it and then the inside of the oven will look intentionally smooth.

Thanks for the input!

I´ve been reading about keeping the mortar btw the bricks to a minimum, and if I´m meticulous when cutting the curved bricks, I could probably assemble the entire vault without using any mortar between the bricks.. Is there any advantage in that? I guess I´d had to cover it in mortar and then add the second layer of bricks, would that be as strong?

[dakzaag]

Nothing wrong with using common brick for mass, use refractory mortar since the temp will go up, although I doubt you will get over 550 F in the mass of the oven. Better to be safe. If you corbel the walls, think about cutting the projection of the brick off before you lay it and then the inside of the oven will look intentionally smooth.

[Fizz]

UtahBeehiver thanks for the link! Truly impressive work from him...

@dakzaak studied his build thread, and got some really good input... Offsetting the vault from the opening seems to be a good way to utilize a smaller vault...

I was thinking of using some old regular bricks I have lying around to add mass to the oven... The curved bricks are two inches thick...