Pizza Bob's 42" Build

[pizza_bob]

Re: Pizza Bob's 42" Build

Hello Dave T.,
I am just south of Waterbury in Oxford - small world! I thought of using the Super-Isol but went with 2.5" thick FoamGlas encapsulated under 3.5" of vermicrete. I really believe heat loss through the floor is a huge problem for cooking multiple pizzas.

Dave W.,
Thanks and welcome back yourself! Hurry up and finish the honey-do-list so you can finish off that oven! I'm looking forward to seeing more pix...

Dino,
I completed 8 courses (if you count the soldier course). I have about four - five more courses to go! Then I need to do the inner arch and flue transition and then the outer arch. I apologize for never answering your Bernoulli equation question...The software can determine effects of a tapered flue and provide numbers for acceleration, pressure, temperature and velocity changes. It really is a great program and I will use it to finalize the flue design. I'll share results if you're interested.

Ciao,
Bob

[pizza_bob]

Re: Pizza Bob's 42" Build

When did others building a 42" oven start to use bricks cut in 1/3's? I am on the 8th course and decided to change from 1/2 bricks to 1/3's. I'm still cutting compound angles on all the bricks. It was nice to cut and mortar only 14 bricks for the 7th course but now with 1/3's I am back up to 24 bricks.... I cut the bricks and will probably mortar them in this week. Also...I haven't used my indispensible tool since course three but think I might need some type of form for these last few courses. I haven't used or needed a form because I mix the HeatStop50 to a consistency that requires me to hold the brick in place for approximately 30 seconds and then move on to the next.
Just wondering what others have done...

[pizza_bob]

Re: Pizza Bob's 42" Build

Memorial Day is the time to remember what our soldiers did and do for us - THANKS!
But it's also the day I finally started working on the pizza oven again! I have been so busy with work that I just haven't had time to get out there. I really wanted to be posting pictures of the first pizza party by Memorial Day but it didn't happen.
Anyway...I decided to change my mind from 1/3 bricks back to 1/2 bricks for the eigth course. I cut all the compound angles on the 1/3 length bricks and started mortaring them in place. What I found was that it was difficult to keep the circular alignment of the course. There was no room for error. If I skewed the brick slightly, the next brick would start to create a smaller circle. Difficult to explain but it was driving me nutz! So I decided to go back to 1/2 bricks and everything seemed to fall in to place just fine. I still haven't used any forms or the indispensible tool . The HeatStop 50 seems to set after one minute of holding the bricks in place - even though they're almost vertical. I'm quite certain the warm dry temperatures here in CT helped too! It looks like I have three more courses to go and then the keystone! Here are some pictures of yesterday's work...

[Dino_Pizza]

Re: Pizza Bob's 42" Build

Looks great Bob. Don't worry, you are on-track:

-Yes, it's maddening that the circle seems to default to getting tighter than you want. It is hard to explain but those side angles are easy to cut too sharp.

-Yes, I also found that after going to 1/3rd cuts, suddenly going back to 1/2 bricks made it work (then it's back to 1/3rds and 1/4's and narrower )

What is your dome/keystone top height looking to be? It looks from your pics that your next course may be quite an angle to flatten out the top. Your brick work looks great btw.

-Dino

[dbhansen]

Re: Pizza Bob's 42" Build

Lookin' good, Bob! Almost there. Keep an eye on those grout lines near the top; it looks like you have the grout lines lined up in a few places, across rows. Might lead to some unnecessary cracking (or so I've been told).

[pizza_bob]

Re: Pizza Bob's 42" Build

Dino,
Thanks for the compliments. The dome height will be 19". I have a wooden template that is 19" tall. I constantly check the height and the courses fall in-line to be 19". I dry stacked bricks along the top of this wooden height gage and the angles look like they will stay the same as the spacing that I have been using. Unless something changes drastically I should be close to the 19". Check out the attached pictures I took at course number four. I just completed course number eight so I have three courses to go and then the keystone! I dry stack on top of this height gage on every course and it seems as if I should be alight with the spacing shown. What do you think?

dbhansen,
Thanks. I have been getting "lazy" with the staggering of mortar joints - I hope this doesn't come back to bite me in the *ss!

[Dino_Pizza]

Re: Pizza Bob's 42" Build

Yup, your gauge looks good. It's so hard to not let those mortar joints line up. You're concentrating on so many things at once. You'll be over the arch in no time.

[pizza_bob]

Re: Pizza Bob's 42" Build

I completed another course and finally had to get my head inside the "belly of the beast" to clean joints. As I finished the ninth course the skies opened-up and started pouring leaving me little time to clean the joints. I was out there in thunder and lightening just prior to the rain trying to finish up. It was difficult for me to get into this oven - probably because I am 6' 6" tall! I kinda' wish I never got in there because I saw something I wish I hadn't! I noticed a crack in the mortar joint between course #4 and course #5! It's a very fine crack along the top of row #4 brick and bottom of row #5 brick. It runs along the circumference for a couple bricks. I haven't done any curing fires yet and a crack already??? I tried to keep a minimal mortar joint, as you can see in the picture, between top and bottom of bricks. I was so disheartened when I saw this crack! I think it might have happened over the winter when temps hovered around zero degress for weeks! I might have had some water in the masonry and it froze. What else would it be??? I'm not exactly sure what to do now but I don't believe I have many options...

[John K]

Re: Pizza Bob's 42" Build

I noticed a crack in the mortar joint between course #4 and course #5! It's a very fine crack along the top of row #4 brick and bottom of row #5 brick. It runs along the circumference for a couple bricks. I'm not exactly sure what to do now but I don't believe I have many options...

Firstly your oven is coming along great Bob so keep up the great work. I like the fact that your are keeping the WFO clean as you go and all your joints are consistent!

In relation to the crack I am sorry to hear. I had a similar issue but was lucky enough I had not laid the next row and was able to repair it easily.

Not sure how big your mortar line is but are you able to grind out an inch or two of the mortar on both the front and back (if the crack is straight through) and point it with mortar? I am not an expert but this will definitely reduce any future risk.

Possible one of the more talented builders on this forum can confirm or suggest a better solution.

Anyway good luck and keep up the good work

regards

[pizza_bob]

Re: Pizza Bob's 42" Build

John,

Thanks for the advice and the compliments about my build.
The joints are so thin on the inside of the dome. I have been trying to maintain an almost edge-to-edge contact in between courses. Perhaps this is where I Went wrong??? The joint tapers back to almost 1/2" on the outside of the dome but the crack doesn't come to the outside. I'm hoping it's just a surface crack that doesn't go any deeper than what I can see. I'll probably try to point it up and let it be. I didn't think I would get by without any cracks in the dome but before the curing fires...ugh!

I checked out your build and I must say very impressive.

I'll post how I make out with this.

Thanks again!

~Bob

[DaveW]

Re: Pizza Bob's 42" Build

You call that a crack?! I'll show you a crack! I honestly don't think I would have even noticed that in our oven. Your bricks look tapered so I think every joint could crack all the way through and the dome would still stand.
I wouldn't even touch it.

Looks great!
Dave

[Dino_Pizza]

Re: Pizza Bob's 42" Build

The dome looks great Bob. Good job keeping it clean. I had a couple similar, very short cracks like that too. I attributed it to some combination of not soaking that brick enough (or too much), having my mortar too wet (or too dry) the day was too dry (or too humid) and any combination of those 3. Your crack may have happened early and you didn't notice it separated as it dried.

Either way: as Dave said, leave it. It's down low and has the weight of the dome on it. You can add slightly more than the recommended 1/4" cladding of mortar to the outside of that joint as I did. I think we all get lots of those kind of separation in small spots and we can't even see them most of the time. The brick is still mortared properly and will do it's job.

Very fine looking brick work and dome, you should be proud.

-Dino

[pizza_bob]

Re: Pizza Bob's 42" Build

Thanks Dino and Dave!

Dino,
You mentioned the exterior cladding. I plan on doing the sheetmetal framing with cement board enclosure. Then I'll finish the exterior off with New England field stone to match my surroundings. Should I still plan on putting cladding around the exterior of the dome? I thought it would just get wrapped with 2" or 3" of cermaic blanket and then loose vermiculite. Is the cladding a must?

Dave,
If this was the only crack I had after curing the oven then I wouldn't be too concerned. But I haven't done any curing fires yet. I'm gonna take your advice, leave it and keep an eye on it when curing.

Thanks Guys,
Bob

[gbohnstedt]

Re: Pizza Bob's 42" Build

Bob,

I'm at almost the same point you are and I'm fascinated to see what your calculations come out to be when you optimize your vent and landing area. My landing area flares much more than most, 22" wide at the opening and 36" wide at the front, so I'm worried about capturing all the outgoing smoke.

I had planned on a wide, deep vent like Dino's 8x20 or so, but I wonder if transitioning to an 8" round at the chimney makes any difference than transitioning to a 8x13 clay liner. Will resorting to only 50 square inches of chimney create a lower pressure in the stack than 104 square inches? You'd think that there should be some difference in the two.

Greg

[Dino_Pizza]

Re: Pizza Bob's 42" Build

Is the cladding a must?

No Bob, cladding is definitely NOT needed. I just assumed you would. I would just put it along your 1-2 joints (outside) that have the minor crack showing on the inside. Cladding in my opinion is not needed, and the danger is it's hard to apply at 1/4" and easy to overdo which just cost more money in mortar, time and more wood to load the oven (unless you want more mass). But, it makes me feel better 'cuz it "smoothes" and evens the look of my ugly dome exterior even though it gets covered in insulation.

Greg: I know of at least 2 others that cut the 8x13 clay pipe diagonally in half, flipped and re-mortared to create a constricted flu vent. I'm sure others just went straight up. Constricting certainly will cause an upward draft. So will length. Maybe others might know if will make a difference.

-Dino