dmun's 36" geodesic oven part II

[dmun]

This post continues the construction of my oven - Part one was in the pompeii thread, and last year's masonry season ended with the oven built and the enclosure built up above the dome.

So: Spring is here, the birds are singing, the flowers are blooming,



and it's time to get back to work.

I first used refractory mortar to attach the two halves of the refractory flue tile funnel together:



I need to offset the flue to make room for the things that are going in above the oven, so the funnel gets tilted back and to the right:



Measuring the amount of bottom tilt needed to make the right side vertical.

[dmun]

Building the fire brick transition

Last year I had completed the dome, and the side walls of the entry. I started brick cutting by raising the side walls up above the dome, and squaring up the hole.



Another view:



This piece of luan is the shape of the bottom of the funnel

[dmun]

Re: dmun's 36" geodesic oven part II

The bricks cut to match the angles of the top of the geodesic dome were really wierd:



The pieces of flooring clamped to the dome are to keep the dry assembled bricks from sliding off the dome as I fit the pieces.

Each of these bricks had multiple cuts at compound angles:



The slope fitted:

[dmun]

Re: dmun's 36" geodesic oven part II

Here's a couple more views of the assembled brick vent:



The downhill brick has a notch to help allign the vent.

Here's a view with the template in place:



The next job is to take it all apart and mortar the bricks in place.

[dmun]

Re: dmun's 36" geodesic oven part II

So, today's first job was to mortar the brick vent transition in with heat-stop.



This view shows clearly that the back of the vent support is built on top of the oven. This may be a bit "squirrel tail-ish" to be ideal, but space in my enclosure is limited



Here's a pic from underneath, showing the two adjecent arches, and the rectanguar opening for the vent.

[dmun]

Re: dmun's 36" geodesic oven part II

Last year I had made a decorative frieze in the basket weave pattern, and one of this spring's jobs was to mortar it together. Doing it freehand wasn't at all successful, so I had an idea. I put the pieces upright in a frame the size I wanted:



I put dry type S mortar mix between the cracks about half way up, and sprayed it with water mist as i did:



A day later it had set up well, although it was sandy on the surface, from washing down the portland with the mist. I mortared it with conventionally mixed mortar. Here's the frieze setting in position before mortaring it in:

[christo]

Re: dmun's 36" geodesic oven part II

Wow! The freize looks awesome. Nice job.

The pics you posted in the photo gallery really show how nice this looks.

Christo

[Xabia Jim]

Re: dmun's 36" geodesic oven part II

Very nice work Dave....from the dome to the freizework and the keystone

an original work of art!

Congrats!

[CanuckJim]

Re: dmun's 36" geodesic oven part II

Dave,

Immediately quit your regular job and travel around the country building ovens. You've done a splendid job. Patience, I understand, is a virtue; one which I lack to the degree you have it. Well done.

Jim

[james]

Re: dmun's 36" geodesic oven part II

David,

Congratulations. Well done. Thanks for all of the time you put into documenting your work so that we could all benefit from both your work and your knowledge. We all appreciate it.

Now, let's get cooking! From concrete dust to pizza flour dust.
James

[dmun]

Re: dmun's 36" geodesic oven part II

Here's the view of the oven enclosure at the current height, almost at the top of the brick section:



You will note that there is an aluminum brick vent installed on the top right. This is a nice little unit the size of a brick that is made for this specific purpose. Here is a blurry view of the inside of same:



An overall view, with maker:

[dmun]

Re: dmun's 36" geodesic oven part II

The final brick layer is in the form of what I was calling dentils, until I did a bit of research. Dentils are on the angled part of a gable, and in classical architecture were intended to refer to the protruding lath that roofing was nailed to in rustic structures. Horizontal bumps mimic the ends of joists, and are called corbels:



Here's what the dry assembled bricks look like, without their decorative angle cuts:



I can't mortar them in yet, because I need access to the inside to build the chimney supports, and insulate the oven.

[dmun]

Re: dmun's 36" geodesic oven part II

Last weekend I built four tapered cast concrete supports in the exterior part of the oven enclosure, with rebar crossing between them. These will support a re-inforced concrete slab at the top of the masonry section, at the level of the corbeling, that supports the exterior masonry of the story-and-a-half high masonry chimney enclosure.

The reason for this is so that the considerable weight of the chimney will not bear directly down on the dome, but be supported by the slab under the oven, and the foundation underneath.

Here's a picture of the wood forms for the rear supports:



You can see the completed supports with their rebar connector in front.

This is a view of the form from the inside, showing the bent rebar loop going down into the leg:



This is a top view, showing the mis-placed rebar touching the flue tile:

[dmun]

Re: dmun's 36" geodesic oven part II

The smoke chamber for the rumford fireplace is bigger than the one for the oven, both at the top and the bottom. It is made of two pieces of 8 by 12 inch flue tile:



The cut pieces line up like this (notice they tilt back):



Here are the two sections heat-stop mortared together:



Notice the two slots cut in the bottom. These are for the hinge bearings of the fireplace damper. Here's the damper blank in position:



My design for this damper didn't take into account the fact that the smoke chamber tapers upward. I had to laboriously cut angles in the damper with the angle grinder, after the welding was done. Note the wrench in the photo, the shaft is squared on the end, and will have a decorative external damper handle, rather than those nasty arrangements where you have to reach up a sooty fireplace throat to close the damper.

[dmun]

Re: dmun's 36" geodesic oven part II

The oven smoke funnel was mortared in place on it's prepared tilted stand:



Now the internal opening around the dome was crudely enclosed with scrap wood:



This was in preparation for the insulating of the oven. Here's the wool blanket shoved around the oven:



Warning to oven builders. This stuff is seriously nasty. Worse than fiberglass. Wear gloves, long sleeves, and a face mask. I'm still itching.

In this picture you get a glimpse of the tops of the chimney supports and rebar. I had to cut the rebar in the front, because it ended up in a place that conflicted with the chimney path.

I then filled all the cavities with perlite concrete, up to the level of the cut arch in the concrete block wall. This should give me about four inches of addtional insulation above my blanket: