Florida Igloo

[dmun]

Re: Florida Igloo

Lets see. The squirrel tail was an American colonial bake oven that had the vent go out the back of the oven and curve back over the oven ceiling and up the front. It had the theoretical advantage of using the hot flue gases to add heat to the dome, but of course it works in the opposite direction once the fire's out and it works to cool the oven with air drawn out through the flue. In addition it has all the problems with the vent in the oven, bad air circulation, etc.

It's not a very well thought out design, because the oven opening is in the back of the firebox of a cooking fireplace. Hair on fire? asks Superior Clay, who hosts this image.

Now a lot of Italian ovens, particularly low dome Naples style ovens vent out through the top of the dome, for aesthetic reasons, like these, at A Mano in Ridgewood NJ:



Now if your oven is freestanding and you don't need to mess with building code, you are free to curve the flue back that sharply from the entrance. If you need to comply with building code, you need to do two thirty degree angles to achieve the center exit. I think the less sharp angles will give you better draw: the reason for the 30 degree limit in building code is that is the sharpest angle you can get a cleaning brush through.

In any event, I'd isolate your angled flue from your dome with a mound of vermiculite concrete. This will keep your dome uniformly hot, and support your offset flue as well.

[RTflorida]

Re: Florida Igloo

I knew dmun would come through with good info...thanks David.

This note is for those who become obsessed and overly concerned about dome cracks...
Look closely at the photo of A Mano in dmun's post. That is a pretty sizeable crack running from the hearth to vent, obviously this is a commercial setting that sees continuous fires and thousands of pizzas.....note - no yellow caution tape and the kitchen has not been turned back into a construction zone over a dome crack. My point is (as stated many, many times by many forum members) ALL OVENS CRACK OR WILL CRACK and it does not pose a problem unless you didn't follow the basics of dome building. If for no other reason, this is a GREAT photo example.

RT

[mstang1988]

Re: Florida Igloo

Starting my formwork now for the hearth. The arch will be a little tricky, but I my Idea is to attach a curved ripped plywood to a 2?x4? every 18?, then run 1?x2? strips perpendicular on the curved plywood at 6? to 8? on center. A thin 1/8? sheet of Luan plywood could be wrapped onto this arch and still support the weight of the wet concrete. It may look a little like overkill, but I?ve seen the disaster of a form failure before an I didn?t want to see it here.

Lee

I was looking at doing a similar design (arch underneath the hearth containing a standalone smoker). I was curious as to how you are going to lay your bricks etc. In my mind was thinking I might use forms and build the smoker with firebricks and leave the forms there after construction (in an arch), lay a layer of insulating cement, then lay they hearth for the oven and insulating layer etc. Is this similar to your plans? If not how are you planning on laying it? Do do you see any problems with my plans?

Btw, it's looking great! Can't wait to get started on mine!

[leemc]

Re: Florida Igloo

Mstang

I don't plan on having the offsett firebox as part of the oven build. My main idea is to provide a conduit at this stage from the outside into the oven chamber. Basically I am going to use one of the unfilled block cells and a blockout in the structural hearth. It hopefully will be more clear once I post my pictures of the hearth pour shortly. My thought is to just use a large terra-cotta planter with a lid on it and some holes drilled in it for the fire box. I would have to rig some sort of duct from the top over to the oven stand and into the conduit. This was I can just bring it out when I plan to smoke something in the oven and put it away when I am not.

Seems like it should work but we will see...

Lee

[leemc]

Re: Florida Igloo

Poured the structural hearth a couple of weekends ago and I have attached pics below. A few comments:

- I forgot to take pictures of the final completed form before I poured. I did some relief on the front of the form that will remain exposed just for decorative purposes. That was the first section I covered in concrete when I started pouring so I had to take a picture of the form after I stripped it.

- I used three bags of sand mix concrete right at the exposed face trying to reduce any honeycombs and to help give a smooth uniform look when I rubbed the concrete after I stripped it. I stripped the form the morning after the pour and just used a wet sponge to rub it and it came out with a nice stucco like texture.

- I did the pour monolithically with a block out for the hearth insulation which is a little different than most here who do a second pour around the insulation layer or insulation blockout.

- You can see the blockout I made with 2x4's nailed together and stuck into the hollow block cell and an angle to get the smoker flue into the insulation layer. When the concrete set up for a few hours I just tapped the block loose and pulled it out leaving a nice flue into the masonry cell.

- I suggest getting some help for this stage from some spry kid like I did with my coworker Matt - you can just spot him in one picture through the concrete dust in front of the mixer. I rewarded him with a handle of Absolut vodka and the promise of a few pizzas in the near future.

[leemc]

Re: Florida Igloo

I could only upload five pics at a time - here are the other ones.

Also bought my Perlite from the local nursery - they had coarse which I understand is better. Hope to insulate my hearth this weekend.

Lee

[Les]

Re: Florida Igloo

Awesome work Lee! This is going to be fun to watch. What is the hole on the right hand side for?

Les...

[DrakeRemoray]

Re: Florida Igloo

Nice work, you are the form-master!

[james]

Re: Florida Igloo

Ooooooo. I like that. Great forms and very well done concrete. Bravo.
James

[larrya1049]

Re: Florida Igloo

Wow I don't feel so bad about moving so slow on my build now. I'm picking up many useful ideas that I can incorporate in my design. Great job Lee!

[RTflorida]

Re: Florida Igloo

Looks like we have a cheater in our midst Lee, you've done this before, RIGHT? Really, Really great concrete form work.
Everyone, another raising of the bar.....we need to keep an eye on this one.

Keep those photos coming, let us know how we can help (although you certainly don't appear to need it).

RT

[RTflorida]

Re: Florida Igloo

Les, I'm guessing that is an ash chute...looks to be on the front side (outside of the entry).....or one of those infamous FL sinkholes.

RT

[Archena]

Re: Florida Igloo

Gesundheit!

[RTflorida]

Re: Florida Igloo

OK, after looking at the pics 3 times and reading this thread again from the beginning....not an ash chute, it IS on the right side. Must be part of the offset smoker mentioned early on.

RT

[leemc]

Re: Florida Igloo

Thanks for the compliments - although I'm not a form carpenter, I am in construction and spent 8 years out in the field so I have seen my share of it. It actually was pretty easy. I just cut some 3/4" plywood for the body of the two side insets and then wrapped the edges with some quarter round trim. The middle oval was a different story. I could not get a good accurate cut from plywood using a jig saw so I ended up buying an poplar oval rossette piece of trim from a lumber supply store here that specializes in trim and doors. I ordered it out of a catalog of wood stair parts our of all places.

Three things you want to make sure you do though if you want to try something like this:

- Make sure you oil your forms.
- Tap your forms with a hammer (or vibrate the concrete)right after you get the concrete against the form to make sure you consolidate it and get any air out.
- When in doubt over strengthen your formwork. Wet concrete puts a lot of pressure on the forms and form failure can be a real mess to fix.

RT - you are right that hole is part of my offset smoker experiment. The flue will be from the fire box on the side of the stand into the empty masonry cell, through the hole in the hearth you see in the picture, into the insulation layer where I plan to extend the flue horizontally into the inner dome. If it doesn't work well - I will just seal it up - but if it works good then I might build a permanent offset fire box there on the side of the oven stand in the future.