Pizza Bob's 42" Build

[Dino_Pizza]

Excellent work Bob! I'm impressed you compounded on the 1st row. It's hard work but I love seeing the same width up and down on those vertical mortar joints. Humidity is great for the mortar, sorry you have to be in too Dino

[mrgweeto]

Rodney,
You're spot on when you said "my time" projects. Our wives wonder why we are so infatuated with the build especially when they see how tired and sweaty we are after 4+ hours of work after we get out of work. We tell them that this is for us. The difference is that we don't have to do it but want to do it. Not like redoing a bathroom (my next project). We start our enclosure today or tommorrw. I spent a couple of hours makeing a decorative flue topper which I will post tomorrow (forgot to take the camera home from work). Came out pretty good if I do say so myself.
Bob,
Nice clean looking work. We are going to have to change your name from Pizza Bob to Rembrandt Bob.
G

[pizza_bob]

Originally Posted by mrgweeto

Bob,
Nice clean looking work. We are going to have to change your name from Pizza Bob to Rembrandt Bob.
G

G,
Thanks. I like that - Rembrandt Bob. It's gonna take me longer than it has already taken me if I decide to taper all the dome bricks. Lets see when my patience runs out.

I had a question about the skim-coat on the dome exterior. I started applying it to the fist couple courses but I'm wondering what its purpose is. Any functional reason?

~Bob

[Rodneyf]

There is no reason at all for the "skim coat" and I only used the left over mortar each time to give the dome a uniform looking finish.

[stevensadler]

Bob

is it possible to get hold of a copy of your plans, in pdf, autocad wanting to start a oven, but not sure where to, if you could that would be fantastic. send to stevensadler@aol.com




I probably should have started my build thread earlier but better late than never...

I'm building a 42" Pompeii style oven. I'm a mechanical/design engineer (mostly medical instruments for surgery) and have never "buttered" a brick before. But I am Italian and must have it in my blood. I have recently become a first time father with the birth of my son Luciano. I'm a triplet (three boys) and 6'6" tall - so yes my cooking hearth will be approximately 50"

I have been obsessed with creating this design in my CAD software (SolidWorks) before I do anything outside. I am pouring my insulation layer today so I've been trying to stay one-step ahead on the computer design. I started laying-out the vent landing area and was looking for some advice.
I have been viewing exceloven's images to get sizes of certain areas of the oven by counting bricks. Has there been any advantages or disadvantages of having a 13.5 vent landing depth? The images below show a that depth and a vent opening that is 16.5" x 4.5". Will a vent opening of this size create too much ofa draw and contribute to problems retaining heat?
I thought exceloven's method of creating the "hard stop" for a door was great! I think I laid it out the same way. It ends-up being a 1" reveal that is created by offsetting the inner arch - very clean looking.
My hearth "sandwich" is 3.5" structural concrete w/rebar, 2.5" Foamglas under the oven and vent landing area, 4.5" of vermicrete at a ratio of 4:1 to provide some thermal mass and then the cooking floor bricks.

I look forward to the rest of this build and discussions with all in the group. I would never had been able to do this without this group.

Thank you in advance!

~Bob[/QUOTE]

[Dino_Pizza]

Hi Bob (and Rodney for this post),

Just to be sure everyone is on the same page, if by "skim coat" you mean the high-heat mortar you smear on the outside of the dome bricks while you build it, then that "cladding" is part of the ovens "mass". You have to decide how much extra mass you want just like you decide on the oven width and height. I wanted a 1/4" of extra mass added around the dome to 1) add mass that heats up and releases the btu's just like the fire brick, 2) gives you the feeling of somehow adding some structural integrity to the dome although it really doesn't but I suspect it might make the joints stronger if you add it to the outside of that joint while it's still moist. And 3) unfortunately it shows all the hairline cracks you'll get when you 1st fire up the oven but that's OK.

Some have added 1/2" of extra cladding, others barely a skim coat. Your oven will heat up faster without it, but with it, you retain more heat for longer cooking times and works better for bread baking.

You can add the cladding while you work on the rings to use up the extra mortar or go back after you're done make sure you have an even amount.

Happy WFO building, -Dino

[dinoforno]

Bob,

I am just curious why did you chose to add the vermiculite layer on top of the Foamglass?

If you have 2.5" and you look at some of the data on FoamGlass wouldn't it just be overkill.

[pizza_bob]

Originally Posted by dinoforno

I am just curious why did you chose to add the vermiculite layer on top of the Foamglass?

If you have 2.5" and you look at some of the data on FoamGlass wouldn't it just be overkill.

dinoforno,
I'm not sure if my reasons for adding 2.5" of vermiculite over the 2.5" of Foamglas are correct but...

Reason #1: Foamglas data does show it to be a super insulator and at first I was going to use 4" Foamglas as opposed to the 2.5". But I thought I would need more thermal mass under my hearth bricks. I went with a 5:1 ratio of vermiculite/Portland thinking that slightly more cement would give me some thermal mass that I am looking for and then the vermiculite and Foamglas will give me the insulation I wanted. I don't think you can "overkill" insulation anywhere on these ovens. If you can fit it and afford it the extra insulation will always help retain heat. I really don't want to keep "recharging" the cooking floor after every pizza. I was told by an oven builder who uses the Foamglas regularly to use 4" of Foamglas and pour 4" of cement over the Foamglas for thermal mass. I thought my heat-up times would take too long so didn't do that - I hope I don't come to regret that when my oven doesn't retain heat well.

Reason #2: Foamglas is very abrasive or gritty when rubbed against another piece of Foamglas or against bricks or concrete. The Foamglas blocks produce powdered or fine particles of glass when this happens. I did not want my hearth bricks resting directly on the Foamglas and risk glass particles coming up through gaps between bricks. I used fireclay/sand/water bed to lay/level hearth bricks but still wouldn't have felt comfortable laying them directly on Foamglas. The Foamglas is also not good with shock or impact. The tapping of the firebricks when leveling might have cracked the blocks too.
So the Foamglas has 2.5" of vermicrete on top of them and approximately 5" of vermicrete all around them. I basically encapsulated them in vermicrete - they shouldn't go anywhere now.

Regards,
Bob

[pizza_bob]

The Labor Day weekend allowed me some time to work on the oven.
I cut compond angles on the second course and mortared them in place. The time consuming part has been the transition from the course to the arch. Crazy looking brick(s) that tie the courses in with the arch. I don't see other ovens that needed to be tied-in so early?? I'm sure it's something I over-thought or screwed-up. I also had time to cut the compound angles on the third course and then dry stacked it to see where seams align (see aerial view below). I'll cut smaller bricks to avoid continuous seams. The bricks that tie the third course into the arch look even trickier than the previous. I'll attempt those cuts tomorrow.

~Bob

[Dino_Pizza]

Bob, your oven is looking great. The joints and brickwork is top notch. What is your final dome height? It looks like your oven will be a 42" low dome and that's great. Or maybe even though you are arching in (having to "tie" in to the arch in row 2 rather than 3 or 4) means your dome will be slightly lower than some. As long as you are on-course with your final dome height, your fine.