Need Advice

[Maverick]

Hi all
i need some expert advise
im a builder so I thought I build my own pizza oven
i formed a 42” diameter dome lathed and plastered the form
let it dr flipped it applied 2 layers of refractory insulation (2300f) then applied 3 coats of plaster over that
on thr front I built an 19” wide arched opening with brick and in the top indtalled a 4” double wall heater duct i then set this on a poured 4” concrete slab with rebar and expansion joints
i mortared around the prrimeter the set a row of brick veneer at the connection, my trial worked okay but i didnt get my temperature hot enough at only 425 the pizza cooked but took about 10mins
i cooked again today but got my fire good and hot at about 850 the pizzas cooked grest and quick, 2 problems, my concrete slab base cracked and a portion of my double wall pipe actually melted, I guess I should have read some forums first, any suggestions?i have room to install some fire brick over the concrete base if that would help, any suggestions on a proper flue pipe?
Thanks

[Gulf]

Hi Maverick,

Welcome to the forum. Not only will you need fire brick on the floor. The brick will need insulation separating it from the concrete. As for the pipe melting, aluminum is the only common piping material that I know of that melts at the relatively low temps that pizza ovens achieve. The double wall pipe that you used must have been designed for use as a vent. A stainless steel flue is what is mostly recommended.

[Maverick]

Thank you
could i use the 1-1/4” thick refractory bricks with the insulation sheet base?

[Gulf]

The thin bricks would probably be fine to save some space in your case (You did not menton the height of your door opening) . Ceramic fiber board is the best insulator per inch. Calcium Silicate board is pretty close behind it. 2" minimum is what is recommended for these insulators. From your description, I doubt that you can raise the dome to get insulation under it. It does not sound like that you have much thermal mass in the dome, so retained heat cooking is probably ouit of the picture.

I did not catch that you said "4" ......heater vent" in your op. I'm guessing that you had plenty of smoke that did not exit the "vent".on startup. 8" ss is what is recommended for a 42" dome.

It would help if you had some pics of the finished oven.

[Maverick]

Here is the oven, the 4" flue worked good until it collapsed from the heat, its only 20" though
Thanks

[Gulf]

If that pic was taken after you cleared the dome, it did perform well? With a 4" flue, I would have expected the face arch to be sooted up at the top. It appears that you have some height for your entry to work with in order to get a brick floor with some insulation underneath. Since you have to rework the flue anyway, it also appears that you could not let the pipe extend down into the entry. That would give you some more room.

[david s]

Hi all
i need some expert advise
im a builder so I thought I build my own pizza oven
i formed a 42” diameter dome lathed and plastered the form
let it dr flipped it applied 2 layers of refractory insulation (2300f) then applied 3 coats of plaster over that
on thr front I built an 19” wide arched opening with brick and in the top indtalled a 4” double wall heater duct i then set this on a poured 4” concrete slab with rebar and expansion joints
i mortared around the prrimeter the set a row of brick veneer at the connection, my trial worked okay but i didnt get my temperature hot enough at only 425 the pizza cooked but took about 10mins
i cooked again today but got my fire good and hot at about 850 the pizzas cooked grest and quick, 2 problems, my concrete slab base cracked and a portion of my double wall pipe actually melted, I guess I should have read some forums first, any suggestions?i have room to install some fire brick over the concrete base if that would help, any suggestions on a proper flue pipe?
Thanks

You need insulation between the concrete slab and the floor bricks

[Maverick]

Thanks appreciate all the input
I’ll keep you updated