Exterior Dome Construction

[Bandrasco]

Re: Exterior Dome Construction

I have a question around the fire brick. Is there any reason I shouldn't use the cut edge to face in wards vs factory edge? My cut edge is sharp, clean, no crumbled edges, no saw blade marks,etc. The factory edges are somewhat less then desirable in a good percentage of them.

Thanks everyone,

[Bandrasco]

Re: Exterior Dome Construction

Thanks RT,

The Vermicrete mix went better than expected; maybe because it doesn't weigh 80 lbs like every other bag I seem to pick up. Since I have so much concrete left (more of those 80lb bastards) I decided to do the insulation just under the area of the floor but went out at least 4" past each side of the floor/wall edge and then I'll poor the rest to the edge with concrete.

With my tile contracting background it was difficult for me not to just treat the vermiculite like screed mud and pack the heck out of it but I didn't read anywhere that that would be a good thing. I would guess it may compress the vermiculite causing it to be more of a thermal mass than an insulator..... So I went with the oatmeal texture which by the way caused a very long discussion with me and my daughter around the proper consistency of oatmeal taking a good 30 minutes out of my build time but wouldn't pass up any time or conversation with her since, as she states, "I'm 15, you can actually learn something from me you know"... Lord help us

Today I'm going to do more work on my arch layout, too many ideas, trying not to reinvent the arch.

Thanks agaun RT,

BTW, what part of Tampa do you live in?

[RTflorida]

Re: Exterior Dome Construction

Give the vermicrete a week...it tends to hold its moisture a while and will be spongy for the first few days....don't worry, IT WILL set up and hold without problems, its just wierd stuff - like thick oatmeal.

RT

[Bandrasco]

Re: Exterior Dome Construction

THE HEARTH IS POURED!!! I managed to get 27 80 lb bags of cement mixed and poured in an hour and a half. I have it covered ready for the HUGE amount of rain thats supposed to hit us in the next hour or so. Vermiculite going in late tomorrow night or early Saturday morning.

Whats a good amount of time to wait until I start on my floor? I have read so many build threads I'm seeing double.

Thanks everyone, and oh yeah....GO RAYS!!!!!

[Bandrasco]

Re: Exterior Dome Construction

Thanks Jim,

If I were to have a pizza party with the expectation of cooking 20-30 pizzas would the extra mass be useful? Also if I was to cook a turkey or a hunk of beast would the extra mass be beneficial?

Thanks for the insight, this forum is great.

[CanuckJim]

Re: Exterior Dome Construction

The major benefit of stacking the floor bricks on edge is increased mass. This will mean that you can in effect store more heat for more bakes in succession without refiring, but it also means that your firing times will be increased. If you plan to do multiple bakes, it's the way to go. If you want quicker heat ups for pizza, lay them flat.

Jim

[Bandrasco]

Re: Exterior Dome Construction

Thanks again.

BTW, just previewed your photo album, great looking oven so far! I plan on having the same type of entry with the wider front. It will allow more people to see the fire while entertaining along with making it easier to get things in and out. Are you finished with your oven yet?

Also, how did you post your pictures? Did you post them as-you-went, or all at one time? Should I post them on this thread or start another?

Sorry for the thousand questions,

[mfiore]

Re: Exterior Dome Construction

Tell me about it. Cutting bricks in 30 degree weather is not fun.

I'm not sure about the vermiculite. I did not use it for my build, using a FB insulating board instead (it's worth looking into).

From what I've seen with other builds, there doesn't seem to be a need to wait. People have put the vermicu-crete down immediately after the concrete. They can cure at the same time.

[Bandrasco]

Re: Exterior Dome Construction

Thanks Mfiore,

I took pics of every step along the way, I just didn't know if I shoyld post it to this thread or start another?

I read a bit more on thermal mass and you're probably right. I do plan on cooking just about anything I can fit in the door way but I'm sure pizzas, bread, and some type of meat over coals will be the most common.

Looks like a rainy day in sunny FL today and tomorrow but Saturday we are having a bitter cold front; all the way down to the 50's in the morning! Not sure what to do. Kidding, grew up in the beautiful city of Chicago, IL. Although I miss the people I absolutely do not miss the weather.

Knowing me I'll have a tarp up after work mixing cement and getting the hearth poored.

What do you think about the Vermiculite poor (or push I should say)? How long after I poor the cement for the hearth can I get that on?

Thank you again for the speedy reply!

[mfiore]

Re: Exterior Dome Construction

What, no photos? We are suckers for photos.

Sounds like you are well on your way. Looks like you've accomplished in one weekend what it took me 3 months to do!

More thermal mass is not necessarily great. It depends on what you are planning to use your oven for. If it is too thick, sure it will have more retained heat (eventually), but will take longer to heat up and use more firewood in the process. I think these big, thick, high mass ovens are best suited for commercial use where multiple bakes are planned, with daily firings.

Just my opinion.

[Bandrasco]

Re: Exterior Dome Construction

Ok everyone, I started! This last Saturday I made my final decision on location (luckily I already had a very thick sound slab in place), I placed and leveled out my first course of blocks, and then Sunday I ran the entire base, angle iron, holes drilled for rebar, bond coated the interior and exterior (it drove me nuts dry stacking them even though I knew I was going to fill them with concrete). I also moved the screen enclosure door, transplanted shrubs, etc (long weekend!). Monday night I cut my rebar, filled the holes with cement that had rebar, and then last night I cut and welded the rest of my rebar for the hearth. I know I could have wire tied it but hey, I never pass up the chance to break out the welder. Tonight I placed all my form boards in place and hopefully tomorrow I can poor my 4" of concrete hearth.

How long should I wait until I put down my vermiculite/portland mix? I am lucky enough to be in the stone business and was able to get a super deal on 5000psi Sakrete that will set in 24 hrs. Not that I'm in a hurry but I'd like to keep on schedule and start setting my floor this weekend. Too soon?

My fire bricks are cut, laid out, ready to go. Well the floor and the first course is any way. Speaking of the floor I had another question. Is it even worth thinking about laying the floor bricks on the side (2.25" length wise vs. flat on the 4" side length wise in an effort to gain more thermal mass? It doubles the bricks on the floor but I got a deal on them and believe I have more than enough. If it will in fact make a significant difference I'll make the change now. It will also allow me to fun the first course full brick without getting too high and then use the cut halfs there on up. Any thoughts on that one?

Thanks everyone, great forum

[Bandrasco]

Re: Exterior Dome Construction

I've seen many of you use a pc of steel with a hinge atached dead center of the floor using it as an angle/height guide. This appears to be a fantastic solution to the possibility of an out of round dome as you go up. I'd like to hear the forum's input on this technique.

Thanks again everyone, this is getting exciting!

[Bandrasco]

Re: Exterior Dome Construction

Thanks Dave,

This forum is loaded with skilled craftsman, great ideas, fantastic photos,and so much creativity that I could not sleep last night! I was looking at brick angles, mortar mixes, hearth designs, floor insulation at 3:55am...Yikes! There are so many ways to create a great looking oven along with being totally functional. I started my shopping list and think I'm going to pick up my bricks tomorrow. I really want to get a grasp on the cuts so don't have to stress about it later on... I'm sure that's going to come anyway .

Thanks again,

[asudavew]

Re: Exterior Dome Construction

I have an inch of therm blanket, followed by dry vermiculite --- 6 inches on the bottom 8-9 inches at the apex of the dome.

I followed that with and inch of mortar, then stucco.

It will get a bit warm to the touch on the outside.....But that's usually the next day.

Dave

[dmun]

Re: Exterior Dome Construction

If properly insulated does the outer dome get very warm?

I have a layer of the refractory blanket, and a bunch of vermiculite concrete on top of that, hard to tell how much because it's inside an enclosure. The outer arch gets hot from the radiant heat, but the other parts of the enclosure are hardly warm to the touch.