Pizza History in the Hammer Continues

[Ope-dog]

Hey Baza, .. I am in the same boat up here in the NW... time seems to be a bigger culprit than $$ on this build. Go figure. lol. Firewood is definitely on my "every-weekend-list," however I'm hoping that the HF canopy I picked up this past weekend will provide enough cover to allow me to work through the winter months on the build. I got the counter top poured this past weekend so hopefully next weekend I can get some moisture barrier down and start getting the base lined up.

Question for you.. what did you use to cut your CalSi board with? Maybe you mentioned it and I missed it? (You supplied great pics in post #44.. and mentioned cutting the board but didn't see what you used..?)

Excited to get going! Bricks and fireclay to be procured this week, although it will most likely be a few weeks before I actually get to cutting and setting..

[Baza]

Hello Forno Friends!

Well, sad to say I'm going in to HIBERNATION! (sigh)
With all the support of Mongo to envision and understand the vent - I just don't have the time. Thanks Mongo! This will be put to use in Spring!

Weather and time getting away from me, ran out of brick (but happily another builder reached out from this forum who is building nearby and was making a trip to get some more supplies for his build and offered to pick up the brick for me! Awesome people on this Forum!). SO, I'll stack and store the extra brick, tarp and tie down the dome, pull down the tent low and hope all is dry and ready to finish in the Spring - for a summer of cooking and enjoyment!

So, no builds for me this weekend, but definitely went to find fuel for the fire!
Neighbour was cutting down some Ash trees at his church and offered the wood to me for my labour!!! HECK YEAH!

So, Valerio and I spent the morning stocking up on some fantastic and dry Ash hardwood - a good day in spite of no build!
At 87 - he's a machine!

All the best friends ... looking forward to following your builds!!
Barry

[Baza]

Chris inPA - thank you for sharing your picture and experience! This is very helpful to consider - and it reinforces, not only Mongo's 8x8 approach (minimum) but this reflection is helpful to us all.
I'm sure that amazing oven you built is churning out good food - but the lived experience of your build decisions is most welcome!

I will be having a go at it this weekend - the flared entry may be a game time decision ... but still leaning this way
WONDERING - does flaring a landing/vent area invite more cool air? Should it be more of a tunnel to trap warm air?

Also - hoping my research on Duravent flanges holds in that the plate is 12" square?

Thanks again for sharing your learning and experiences friends!
Barry

[Chris inPA]

This is my throat from below looking up. I wish I would have done an 8 inch chimney stack and not a 6". Opening up the throat like this does give me more square inches than the 6" id pipe. However, it wasn't enough. I get a lot of smoke out the front. Enough that my bricks are black.

[Baza]

AH! I see!!!
Right - so the beautiful sculpting you did on the throat brick actually widened the throat in the vent to make a smoother transition of smoke TO the chimney.
Makes sense.

I read somewhere that lighting a fire under the chimney (even burning paper/pine cones) even IN the chimney briefly heats it up so the cold air in it doesn't wrestle and push out the warm air trying to come up it!?
Sounds like it makes sense.

Last question I have before the outward flare of the opening.
I noticed, Mongo, that you used full and half bricks the length of your vent ... as such 13.5" ... you've stated this before.
You also noted that you didn't flare the opening but have a wider reveal.

My question lies in the potential loss of vent length if I flare it ... the angle of the flare from 22" at the door to 25" at the mouth will have to be compensated for in the heat break cuts at the mouth of the dome.
As such - this slight angle has the potential to pull the length of the vent in more than a non-flared opening.
in fact - it makes the lip-design you shared harder to do.

in my head it suggest the 1/2 brick cuts around the throat will be cut again to 2.5" at the dome opening arch and about 2" at the vent opening arch ...
The 2.5" cut at the mouth of the dome would be made smaller again by the need to flare at the sides - compromising the lip. no?

Too much thinking perhaps - any thoughts?
Barry

[mongota]

That's one of the reasons I flared the opening of my chimney throat, to increase the initial opening size help coax a more laminar flow of exhaust gas up the throat and into the chimney flue.

The underside of my square throat is flared out for a larger opening, it's roughly 10" square, of 100 sq inches.
The actual dimensions of the throat at the top (square sides, without the flare) is about 8" square, or 64 sq inches.
My chimney pipe is an 8" ID round, or about 50 sq inches.

That stepped approach from larger to smaller (100>64>50) seems to work well on my oven.

I do get a bit of smoke coming out of the front arch when initially starting my fires on the landing floor, right under the throat and just inches from the front arch. Once the fire is burning, most everything goes up the chimney. My chimney is a 4' tall length of double-walled pipe. Once the fire is burning well and I move it back on to the dome floor, I get zero smoke out of the front.

[Baza]

Chris inPA - thank you so much for sharing your build pics here! This is very interesting and I certainly don't blame you for riffing of Mongo's idea! It's good stuff!
I feel like I'm headed in the direction of both you and he ... though I am intrigued with your comment above that you would have preferred a wider throat instead of building one the same size as your chimney (as Mongo did) ... why is that?
Barry

[Chris inPA]

Insulting tape

[Chris inPA]

Between the arches immediately before insulation.

[Chris inPA]

mongota I loved your ideas of separating the inner and outer arch with a section of rope. I copied your idea using tape, so far it looks like it worked well.

[Chris inPA]

Baza I did a 6" chimney with a corresponding throat. If I could change 1 thing about my build, that would be it. I should have made my throat more generous.

[mongota]

Here's a photo of my vent throat from below, from the floor of the tunnel looking up through the chimney pipe.

The square opening is the ~8" square in my tunnel arch.

You can see how that square 8" opening in the tunnel arch transitions to a ~8" round hole, that 8" round hole is in the transition bricks that sit atop the tunnel arch, my chimney anchor plate is secured to those transition bricks.

And you can see the 8" round stub pipe on the bottom of the chimney anchor plate, and how it nestles inside that ~8" round hole.

[Baza]

THAT

IS

AMAZING!!

mongota Thank you for taking the time to not only answer my questions but visually support the answers with mark-ups of the photos!
This makes a GREAT DEAL OF SENSE - as your replies always do for folks you support!

So an 8" square throat leading up to an 8" chimney pipe stub - got it!
Some have a larger opening - not sure if it gathers more smoke for the chimney - but reading that your draw is good - then I'm convinced!

Thank you again, Mongo!
Barry

[mongota]

Barry, See my marked up attached photos...as you know, these details can be done in myriad ways. This is what worked for me...

Photo #1: Cutting the brick as shown afforded me a 1-3/4" reveal on the inside of the dome arch. The outward offset of the tunnel bricks is the combination of the 1-1/4" lip of brick and the 1/2" thickness of the ceramic fiber rope. My landing tunnel is not flared, and to minimize the likelihood of my thick insulated door catching the inside walls of the tunnel when placing or removing it, I went with a large 1-3/4" reveal.

Yes, there is a bead of RTV silicon in that gap, roughly indicated by the red circle in the photo. I applied that bead as I mortared those bricks in place.

Photo #2: 8" x 8" square. When I later installed bricks on top of the tunnel to create a flat surface for my chimney anchor plate, I cut a ~8" round in those transition bricks to accept the ~8" round pipe stub coming off the bottom of the chimney anchor plate. The chimney draws quite well.

Photo #3: Same bead as the one indicated in Photo #1. The bead was applied about 1/4"-3/8" back so when the bricks were set and the bead slightly compressed, RTV squeeze out on to the face of the arch bricks would not be a factor.

[Baza]

UtahBeehiver mongota I really need some insight on your builds!

I'm ready to build the vent and have some questions - they are in the pics attached (you both should recognize them!) - essentially I'd like to learn a few things about your heat-break approaches (ie/ touching/not-touching) and the throat size for your chimney vents.

Can you please have a look and consider your wisdom in light of these questions?

Humbly
Barry