Flying Saucer

[Neil2]

First - dig the holes. I used a hand held post hole digger to go down about 4ft. The last foot was tough going and I rented an electric jackhammer with a long bit to loosen it up. This "pile" system would also work if you are worried about getting below the frost zone in clay clay-till soils. Next I supported a couple of 3/8 re bar in the holes and pored in concrete. The part that will be underground does not need the carboard tube forms (unless the soil is really granular or sandy and keeps caving in). The carboard tube forms are readily available at your local lumber yard or builders supply. After pouring the tubes, I bent the rebar and formed up a 5/8 in plywood platform to support the 4in structural slab pour. The last photo show it ready for the concrete. The circular shape is achived uisng strips of lighweight pegboard lined with tech tape curved against blocks screwed to the plywood. The ash drop opening is formed with a peice of 4in pcv pipe wired down. Note: always try to use round shapes, avoid square "inside corners", for openings in structural slabs.

[Ken524]

Re: Flying Saucer

Excellent pics! Keep 'em coming. That's a really neat project.

[Neil2]

Re: Flying Saucer

After pouring the 4 in structural slab, I "climbed" the form up a couble of inches to support an inner ring to act as a form for the 5 in insulating layer. This is 6 parts vermiculite, 6 parts perlite and 1 part normal portland cement. The second photo shows the forms off and the hearth layer on top of the insulating layer. Next I started the dome. I found I could go up about 4 courses without internal support. The last photo shows how I used screws for spacers to hold the angle until the mortar set. The angle changes a bit for each course so I used 1 1/4 in screws, 1 in screws etc as needed. The mortar is refractory mortar. This was buttered on for about the first 1/3 of the brick on the inside tight joints. When I used refractory mortar for the wider part of the joint I found it shrunk and cracked when setting so for the outside wider part of the joint I used a mix of 1 part refractory mortar to 3 parts sand. This may actually be stronger than the neat mortar for the wider joints.

[jengineer]

Re: Flying Saucer

love the foundation - taking an basic design and making changes to it to make it your own. Nice evolution

[Neil2]

Re: Flying Saucer

Thanks Ken,Jr
The remainder of the dome was built on styrafoam supports. This was a tip I picked up from this forum and it worked great. When I started, I rented a proper masonary saw with water bath to do the bulk cutting into 2/3, 1/2. and 1/3 bricks. Did all the cutting in a couple of hours. As you move up above the 4th course or so, you have to start doing a "bevel" cut on each brick to keep the inside joints as tight as possible. I did this using an ordinary chop saw with a masonary blade. I soaked the bricks in water for 1/2 hr so that the blade was "wet cutting". If you cut dry bricks the blade will wear out fairly quickly. In the second photo you can see a bundle of cheap chopsticks which I used to bridge between the styrafoam supports as needed to hold the bricks as I worked up. I took my time, doing a couple of courses at a time and letting the mortar set up overnight before doing the next two courses. Last photo is me inserting the keystone set.

[fullback66]

Re: Flying Saucer

Everyday that I look at this forum someone impresses me. Great work Neil. That is a very unique design.
fb66

Send more pictures.

[Frances]

Re: Flying Saucer

I like it, too!

How on earth do you make a heavy thing like a brick oven look as if it is floating? It looks really good.

[Neil2]

Re: Flying Saucer

Thanks all.

The hardest part to figure out for me, was the opening and lintel. I actually tried a couple of different things before hitting on the one I used. It is hard to describe clearly. Basically you will need two lenghts of angle iron - I used sections of the "T bar" reinforcing you can find at lumber yards. Because my entry is tapered the two pieces are of unequal lenth. The innner one goes in while building the dome and supports the dome. the outer one helps supports the vent. Outside of the vent, I formed up and poured a layer of the vermiculite/perlite insulation. Note the pale white bricks. These are lightweight insulating brick I got from a potter (potters are a good resource for materials and techniques). These form a thermal break for the outer lintel which is poured rienforced concrete. The aim was to keep the opening fairly shallow so I didn't have to reach in a long way to tend the fire and food.

[Acoma]

Re: Flying Saucer

I got an idea, why not the FB olympics? Who can make the fastest oven with best character and draw of smoke? Maybe relay teams? One to 3 members per country?

[Neil2]

Re: Flying Saucer

The first photo is of the 2 in poured reinforced concrete "belt" that holds it all together. This extends up to the height of the first soldier course. The second photo shows the screeding frame for the 5 in thick vermiculite/perlite/cement insulation layer. The final finish is two coatings of acrylic stucco painted on. The third photo is the concrete table. I set the height of this level with the hearth floor at 43 1/2 inches. My wife wanted it high enough so she would not need to bend down to see in. (I have a 5ft 4in wife - if you were issued a different size one you may need to adjust the height.) The table is 1- 1 /2 inch concrete, poured with a little green conc dye added. It was then ground smooth and polished. I set it tangent to the oven at about a 45 degree angle to the door. This allows you to get near the opening without reaching over a table and still provides a convenient working surface. The last photo is a shot of inside of the brickwork (before cleanup and firing).

[fullback66]

Re: Flying Saucer

neil,
What is the process of polishing the concrete? That looks really good. I would like to give it a try.
fb66

p.s. do you have a door?

[Hendo]

Re: Flying Saucer

The first photo is of the 2 in poured reinforced concrete "belt" that holds it all together. This extends up to the height of the first soldier course.

Neil,

Do you have any photos of the detail? I?m interested in the reinforcing & formwork etc.

I?ve been thinking about pouring some buttressing like this, but using an insulating castable refractory as I don?t want to add any more thermal mass to my oven. Johnrbek (offline since May) went down this route for his ?true Neopolitan Pizza Oven? ? see http://www.fornobravo.com/forum/f8/f...oven-1453.html and Low Dome Neapolitan Oven Update - Dome Construction. Photo Gallery by John Bek at pbase.com

Nice looking oven!

Cheers, Paul.

[Neil2]

Re: Flying Saucer

Fullback66

Here are some pictures of the door. It started out as a damaged aluminum road sign. By pure luck it was exactly the right height to fit the inside lintel. Since my door opening is tapered, I simply bent back "wings" to match the taper. Forms a failrly tight opening. The bent wings also also it to stand up so I don't have to prop it against something when it is not in the door. The second photo is looking down on the top edge. I used some leftover aluminum channel from my soffit redo, pop riveted these top and bottom. The insulation is the type that is used to insulate electric ovens. A heating supply place will probably carry it or you can stop by your local dump/recyclers and fish out a piece from an old stove. The temperature gauge is from an old barbecue . It only goes to 700 f but is useful when you are baking bread or slow cooking a roast. The handle is a Marshaltown trowel handle - this is not connected directly to the face ( it burned when I did this). I formed a sort of "stand off" bracket out of plumbers strapping.

[Neil2]

Re: Flying Saucer

Paul


"I’ve been thinking about pouring some buttressing like this, but using an insulating castable refractory as I don’t want to add any more thermal mass to my oven."

Try it. One thing about pouring (and then grinding) is that you can get pretty much any shape you want.

I did two pours for the opening. The first was a vermiculite/perlite/portland cement mix. Although this is not a refractory (because of the use of portland cement) it is fully contained by the second pour and the shell so that when it breaks down it will stay in place. Here are a few more photos - I hope they help.

[Neil2]

Re: Flying Saucer

fb66


"What is the process of polishing the concrete? That looks really good. I would like to give it a try."


This could take a whole thread by itself. Concrete countertops are suprisingly easy to make - they just take a lot of hours grinding and polishing. Very simply:
-Pour concrete. 1 1/2 inch thick. Use the bags of pre mix - they tend to have a more vairied stone colour than crush. Add some concrete dye if you want. Put in some inserts for tie downs and pot hangers.
- Let set 3 days. Shape edge and grind off surface layer exposing and cutting into the aggregate. Use a 5 in angle grinder with a diamond cup grinder. Do this all wet.
- Keep wet and let set another 20 days. Now sart in on the wet polishing. You can get a set of 4 in diamond pollish pads (the 4 in pads will work fine on your 5 in angle grinder). A 50 grit-100-200-500-1000-3000 grit set will work. Note this is very messy. You can get almost a mirror shine without any coating or covering. Totally food safe and heat resistant.