Pizza Bob's 42" Build

[Dino_Pizza]

Re: Pizza Bob's 42" Build

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.

[pizza_bob]

Re: Pizza Bob's 42" Build

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

[pizza_bob]

Re: Pizza Bob's 42" Build

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

[dinoforno]

Re: Pizza Bob's 42" Build

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.

[Dino_Pizza]

Re: Pizza Bob's 42" Build

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

[stevensadler]

Re: Pizza Bob's 42" Build

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]

[Rodneyf]

Re: Pizza Bob's 42" Build

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.

[pizza_bob]

Re: Pizza Bob's 42" Build

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

[mrgweeto]

Re: Pizza Bob's 42" Build

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

[Dino_Pizza]

Re: Pizza Bob's 42" Build

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

[pizza_bob]

Re: Pizza Bob's 42" Build

Thanks Rodney! I can only hope it goes quicker than it did this week.

I finally got some time this weekend to mortar the first course. I cut compond angles on the the bricks to minimize gaps and large mortar joints - I'm not sure if it was worth the headache but I think it came out okay. It was so HOT in Connecticut this weekend and I'm hoping it doesn't effect the curing of this course. I worked under a canopy so there was no direct sunlight but temps were in the 90's and humid - perhaps the humidity helps??
I also set-up the adjustable indispensible tool which wasn't neccessary for this course but did help maintain the circle and should help in the remaining courses. I also cut-out a template from particle board for the inner shape of the arch. I'll use that as I go to ensure I'm staying on track for a 19" dome height...

~Bob

[Rodneyf]

Re: Pizza Bob's 42" Build

It all looks good so far and you will be moving pretty quick from this point. I found I slowed down when I got closer to closing the dome and then once it is closed you will go ahead in leaps and bounds. I have been seen outside at 10pm with a miners light on my head working on cleaning the joints I have done that afternoon after work. Enjoy your build, I think that is why we are doing this after all. I am not sure it is all about the pizzas, some of us just need a project to give us "my time".

[pizza_bob]

Re: Pizza Bob's 42" Build

Guy,
Nice job with your build! The keystone looks great! Congrats on the first fire!

I had no time to do anything today. I pulled the form for the arch and that's it! I think it's time for a "stay-cation" in the back yard...
I need to clean-up mortar that oozed out of the arch joints tomorrow. Is it best to just chip-away at the oozed mortar? Now I move on to the second course of the dome - my indispensible tool will finally be tried out!

~Bob

[mrgweeto]

Re: Pizza Bob's 42" Build

Bob,
I think it looks great. the 5th bricks left and right as you pointed out have a slightly bigger joint. Except for you.......who cares. Remember that for most of us we are not masons. When you come over and see ours I'm sure you will be able to see some inperfections. Anyone that is gont to come over to see the finished procust will be in awe. I know because the few that have been following our progress are astounded at the oven. Most/all people have no clue. We went up a second flue today and ran out of brick so we are going to pick up the few more we need and look at some tiles for the hearth. We lit a few very small fires and I'll tell you that it is very impressive to not only see the draft working but to hear it going up the flue. One half piece of the front page of a news paper and you can feel the heat in the upper portion of the dome.
Don't beat yourself up with being dead nuts because you are working with a medium (mortar) that can't be exact. Very close but not withing 1000ths as you are use to. Your arch looks neat as a pin. Will send you some pix tomorrow
G

[pizza_bob]

Re: Pizza Bob's 42" Build

Mr. Gweeto,
Congratulations on finishing that dome and lighting that first fire! That's got to be a great feeling! I feel as if I'll never get there at the rate I'm going. Send some pix when you get a chance.

So my arch building skills need some improvement. Luckily this is the inner arch which is mostly out of sight. The dry stack arch looked so nice but to keep those mortar joints consistent was challenging! I ended-up soaking the bricks for a little bit to help make this process easier. I also drew lines on my wooden form that showed where each brick should be placed - on the inside of the arch. The problem was that there was no marking for the top side of the arch! I ended-up not spacing these properly and didn't notice it would be a problem until I got to the wider joints you see in the attched picture. I determined that I needed to go with this wider joint on each side in order to prevent a situation where the mortar joint gap at the top side of the arch was actually smaller than the gap at the inside of the arch. I called this a negative angle and the only way to eliminate it was to go with a thicker joint (1/4") in the two places shown. The other issue was...as I was working from left side towards the keystone and right side towards the keystone, the bricks started to skew. The left side was skewing out towards the front of the oven while the right side was skewing towards the back. I again didn't notice until the last few bricks so had to make a noticable adjust (a step) to correct it. Most of this won't be seen but the 1" door reveal will have a slight step in it and the door will not sit flush against the reveal. I ended-up buttering both ides of the keystone before placing and it needed to be lightly tapped into place. I purposely hurried to get the last 4 bricks in place so when I tapped the keystone the mortar joints of these last four brciks would flow while I tapped the keystone in. It seemed to work well - as the keystone was tapped into position the joints around the keystone and the last 4 bricks had mortar pushing out slightly. I'm not sure if I should have been tapping that keystone in place but it seemed like a good thing to do at the time. How do you know if your tapping the keystone too hard??? I didn't see any cracks or separation in of the other joints but now I worry that this arch will have residual stresses from the tapping of the keystone. It seems really strong though! I wonder if I can remove the forms tomorrow???
Overall...I' m okay with how it came out. I don't mind the joints being slightly larger in two place but I am not satisfied with the skewing of the bricks. If you look at the picture you can not notice it because the mismatch is "in and out" of the screen. The bricks to the left of the keystone have a small step coming out at you and the bricks on the right have small step going into the screen. Again...most of this will be hidden/covered- up but will it make it more difficult for me to create the vent area arch??
I'll work on the second course today - so I finally get to try out my indispensible tool!

~Bob