Tapir Force Steps up to the plate!

[Tapir Force]

Re: Tapir Force Steps up to the plate!

Today, I got caught back up on the opening to the oven. I had enough of my 15"x12"x2" firebricks, I decided to cut the layers to the entry that would include a reveal as so many have suggested. I cut 4 of the blocks per each side, but by the time I mortared and placed my arch, the opening exceeded the 60% of the inside height of the dome rule. I took a layer off and that brought the height to 6" before the beginning of the entry arch. The ratio went back to within the proper range so that I do not lose too much heat. I am going on a trip for a few days, but will try to mortar in the front tomorrow before I leave. Next week I should get to setting the tiers.

[Tapir Force]

Re: Tapir Force Steps up to the plate!

Today, I cut back my firebrick floor. Ding, dong the wick is dead! I then proceded to mix up some more vermiculite concrete and poured the insulating mix around the floor where the firebrick had been. I believe I have solved the problem and I will start cutting my first and second tiers.

Dino,

I was thinking about a 21" dome. I have read much about both types and find that the arguments for both shapes are compelling. But since I can't make a choice based on the merits, I think the full arch looks a bit more ancient to me. I am all about old.

[Dino_Pizza]

Re: Tapir Force Steps up to the plate!

Filling in with loose vermiculite is the way to go, wish I'd a done that. And it's good to here your going to "modify" your floor that extends beyond the soldiers. You might as well do the extra work now for a good working oven.

What's your final dome height going to be? Are you planing on a half-sphere at 21" or a squished elliptical a bit lower, like 19" ? With your soldier course already at that angle, your 1st row or 2 may need none to little tapering .

It's looking,
Cheers, Dino

[stoveup]

Re: Tapir Force Steps up to the plate!

Right - you have the insulation underneath covered and, if I understand your modification to the subfloor, it will allow you to insulate down to the vermicrete slab so your oven can be completely wrapped by an insulating layer. That's the ticket.

Keep on keepin' on!

[Tapir Force]

Re: Tapir Force Steps up to the plate!

Stoveup,

There is a 3.5"reinforced concrete floor. On top of that is a 3.5 inch slab of vermiculite and Portland cement insulating layer. Then there is a layer of 12"x15"x2" firebrick floor on top of the insulating layer. Then the oven floor and soldiers. I am modifying the 12"x15"x2" firebrick floor as it turns out that it will probably wick off too much heat in its present configuration. Thanks for looking in!

[stoveup]

Re: Tapir Force Steps up to the plate!

Tapir,

That's a great start. I can't see it in the photos so I'll ask - is there insulation below the oven floor and the soldier course?

[Tapir Force]

Re: Tapir Force Steps up to the plate!

Here are my soldiers standing around waiting for me to repair my design flaw of taking the firebrick subfloor too far beyond the perimeter of the dome.

As I am working on this project, I am doing it with an audience of four parrots in outdoor flights and two scratch and dent rescue dogs. They seem highly amused as begin taking this apart to repair my floor.

[Tapir Force]

Re: Tapir Force Steps up to the plate!

Dino Pizza,

The dome gives me about 2.5" for my insulation on the outside of my soldiers. But I intend on using concrete board on the outside of the enclosure and filling with loose vermiculite. That gives me an addition 3.5"on each side. I did something similar on my gasification boiler and although temperatures are not as high (never over 200℉) the insulating properties are amazing. I have looked at a lot of your posts. Your kind words mean a lot.

Robert

[Tapir Force]

Re: Tapir Force Steps up to the plate!

This is of course why I signed up to share my build on this forum. I will in fact be trimming back my perfectly flat, uncommonly neat, and lovingly placed floor. As some have noted, I am going at this thing with fervor. I have some big greenhouse projects in front of me and I want this thing (at least the dome part) done fairly soon. But of course, as I have already demonstrated, I am proficient at bonehead moves, so I must not go too fast and keep my pictures coming so that the masons on this site can help me to learn humility.

[GianniFocaccia]

Re: Tapir Force Steps up to the plate!

Ha! No way a screen name can compare to a warm-blooded red head named Lugina!
If I had a do-over I think I'd pick a screen name that was easy and real short, like: Mo Betta or something.

Practically speaking, cost of the firebricks aside, each time you fire your oven you will be heating 'external dome floor' that you can't use, except as a Quasimodo heat sink. Further, this wing-like structure, while nicely insulated may act as a cooling fin, spreading out the exposed cooling area instead of neatly tucked under the oven itself. I believe the rate of heat loss may exceed the conduction of stored energy back into the dome as usable heat. Of course I'm not a heat-transfer specialist like my late father-in-law was, but I did stay in Holiday Inn once.
John

[Lburou]

Re: Tapir Force Steps up to the plate!

Robert

Uncommonly good start!

I get your point about the sub floor not touching anything to transmit heat, but I see no value added to extending the sub floor out that far, in fact I agree with the guy with that Italian name

Its not too late, consider reigning the sub floor in a bit and I think you will be better in the long run for cooking temperatures 72 hours out from cooking pizza.

[Dino_Pizza]

Re: Tapir Force Steps up to the plate!

Nice build Robert. Congratulations on starting and ah...well, almost finishing . You've been going quite fast and that's good. Enjoy every minute of it.

My 42" was on a block stand and framed with steel studs too. I see your stand is 4 cmu wide and 4.5 deep. I was a 1/2 cmu bigger on both dimensions. 4.5 - 18" blocks deep is fine, especially if you have a slightly cantilevered counter or don't need a deep one. With 4 blocks wide though, you'll have to squeeze the insulation blanket in b/c I only had 2 inches to spare and mine was wider.

I like your finished blocks on the stand. I guess they are some sort of split face? (not sure the terminology) but they look good. A 20 deg cut on the soldier is fine if a tad old-school. People are having an easier time doing it like John did but no worries, a taller soldier course work fine.

Good job on the herringbone floor too. Keep up the good work and the pics to look at,
-Dino

[Tapir Force]

Re: Tapir Force Steps up to the plate!

Gianni Focaccia,

My goodness, with a name like that you must be a direct descendent of the Roman God of Pizza. Thank you for your remarks and opinions. Of course I am most interested in your remark about the firebrick floor. The slab rests in its entirety on Vermiculite and Portland cement. It goes out to what will be steel studs for framing and have a heat break of high temperature insulation blanket before touching anything. All of the dome will be blanketed and then the entire void in the remaining cavity will be filled with vermiculite. I see some designs where the dome sits on a larger pad of 4.5x2.5x9 firebrick and as you suggest, I suspect it does pull some heat, but if that gets hot, and then does not touch a wall or a large uninsulated slab, is it a substantial loss? I am still at a point where I can cut part of it away to reduce the loss, I just don't know how to figure if the loss is manageable or not. I guess I got to rolling and found that slab on a slab to be very neat and flat. But it isn't about neat and flat. It's about cooking.

On a side note, when I was an undergrad I dated a girl from the North of Italy named Lugina Andraghetti. She had deep red hair and a charming accent. I thought I would never meet anyone with a name more Italian sounding than hers. But now I have met you.

[GianniFocaccia]

Re: Tapir Force Steps up to the plate!

Great start on your project, Robert. Four pallets for $7! Are you kidding? Do you know what those would be worth 'down under'? I'm guessing you'll have plans for a second oven before you're finished with the first one.

FWIW, you may want to consider modifying your firebrick sub-floor. I'm a proponent of extra mass under the oven, but your floor extends out past the perimeter of the dome and will certainly wick heat away during and more importantly, after firing.

As far as Doug's suggestion, I may be wrong here, but I think he meant to make the first two courses horizontal, not vertical. I tried soldiers but couldn't get them to bond worth a damn in 100F heat. So I went to horizontal courses and never looked back. I decided to remove the angle from my already-cut soldiers and ended up with a 5" deep first course. I went with a 4.75" second course and 4.5" courses from there on up.

John

[Tapir Force]

Re: Tapir Force Steps up to the plate!

Karangi,

I had already cut my soldiers on a 20 degree angle by the time I got your post earlier. I would like to see some pictures of what you were discussing even though I already made the cuts. Always interested in different methods.

Robert