Collapsible form

[james]

I rec'd a series of photos the other day that were interesting for a couple of reasons. First, the oven has a really nice pure-brick finish that looks great. Also, the builder used collapsible forms to keep a consistent inward curve.

Take a look at:

http://fornobravo.com/pizza_oven_pho...ouisiana1.html

James

[Keith Oertli]

That is a good way to keep your curve consistent.

In his picture he shows 4 vanes on his form. I do the same thing except I use a single vane.

I find exact center for the dome and mark it. I then rotate the vane around the the center as I lay each brick.this lets me stay very accurate with my chains.

K.O.

[james]

I was thinking of using a stiff foam board that I could break out at the last minute.
James

[ColonelCorn76]

The multiple vanes allows the form to be more stable I would think than a single vane. Very nice solution. How do they collapse out?

Using foam board (2" insulation board) would make a very nice form and is easily broken out when the time comes to pull it from the oven. The board is usually available in 2' widths so it wouldn't be a problem to do up to a 48" oven without having to pin a couple of boards together.

This is similar to my sand form concept (using a dowel in the center with an arch curved vane to smooth the sand pile into the proper shape before beginning the arch). All of these forms will make the construction a bit easier as the builder won't need to rely on the mortar to hold the bricks to the ring while building. Be easier on the upper reaches too where until the last one is in, it doesn't lock and you need a helper or a form to keep the rings in place.

Elegant.

Jim

[Marcel]

Last courses of the dome have many different approaches

(M) Dear Luis,

(M) I have ready of many different ways to support the dome during construction. Each method seems to have it's adherants.

(M) You, Luis "build the dome using 16 polystyrene vanes in place of 4 like our friend jcdup did"

(M) Some like Keith, below

[QUOTE=Keith Oertli]"That is a good way to keep your curve consistent.

In his picture he shows 4 vanes on his form. I do the same thing except I use a single vane."


(K.O.) I find exact center for the dome and mark it. I then rotate the vane around the the center as I lay each brick.this lets me stay very accurate with my chains."

================================================== =====

(M) I did a Search on this Forum for "Vanes" and found so many entries that I couldn't read them all. I have read a view, expressed I believe by either Jim, or James, that having fewer vanes allows the builder to see inside the dome as s/he builds. Fewer vanes may also allow for an easier rotation, but many vanes provide stability. I don't know where to find a middle ground ???

(M) I hope to pour the foundation slab tomorrow so I am too far away to make any intelligent suggestion. But after reading all these views I do have a question:

(M) If I use a "Lazy Susan" (a plate that rotates on a bearing ring) and choose one that will pass through the neck-entry of the "igloo", would it be significantly easier to rotate the vanes whether I use 1, 4 or 16 vanes ? _____

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(M) At "Jerry's", my Home Center, they offer a denser foam board. It is not solid insulation. It is pink and about twice the cost of the white styrene but still only $6 for a 4x8 sheet. Unless I hear from more experienced builders that using this material is a mistake, I plan to use it. I figure that if I go with fewer vanes (probably 4?) that the pink foam will be less likely to break during construction. Comments? ______

Thanks,

Marcel

[paulages]

marcel,
personally i think the 16 vane method works great, though indeed you cannot clean as easily as you work. the major advantage--and the point where it is hardest to clean--is when you get to the top, and you already have forms in place when gravity takes over. i'm a bit of a perfectionist, and so i was annoyed at the random bits of mortar hanging into the dome in the top after i pulled my forms out, but i just tapped the excess loose with a hammer before i fired it and you know, you'd never know the difference.

[PizzaMan]

I'd use Paul's multivane, or the wire loops

I just finished my oven and didn't have the advantage of all of Paul's great ideas ahead of time. I set the few few rows with only the single vane as a guide for the curvature of the dome and they looked great. Of course, when I realized I would need some sort of support as I began to "turn the corner" moving upward, it was too late to place the nice one Paul had been using. (He was about two days behind me on the build, I think.)

At any rate, I had to be a little more creative than I wanted to and came up with a similar solution, though not as pretty. I'm happy to say that it all held and I am a happy man!

One suggestion for those in the building process: Take the time to use a masonry blade on an angle grinder, and start tapering the edges of the bricks at the point that the gaps begin to open up on the inside surfaces. I began doing it on about row 6, which really closed up the gaps and made for a cleaner, smoother and stronger dome. I would definitely have begun it earlier.

Good luck to you, and enjoy!

Michael
aka PizzaMan

[paulages]

great advice about tapering the edges! on row 10 or so, i actually trapezoided (just randomly cutting actually) every brick, and they fit together really snuggly. if you are using a 10" wet saw, i would go a little bit further and use a bit of jim's engineering (in another thread), and cut every brick like that. the gaps really open up towards the top, and those last few triangular keystones are really kind of a pain in the ass. it would be nice for it to just close in properly at the top, but would require a bit of thought to execute.

[PizzaMan]

Tight fit is worth it

I was very careful with the last several pieces. I wanted them to be very snug as they would be the final sources of strength.

I surprised myself by cutting them so carefully that I could not fit any mortar between the last 6 or 7 pieces. When I had a 12" circle open at the top I careful cut them like puzzle pieces to dry fit, then ended up tapping them in carefully together into playce with the rubber mallet. It was simply too close to fit any other way. Then I forced a little morter into the small joints on top.

I immediately removed the support vanes, to make sure I fixed it before any mud stiffened up. I found it was strong and tight enough to put significant pressure on the top of the dome without anything budging.

I was a happy man!

Michael

[Marcel]

Humor in a jugular vane with Lazy Susan

#12

(M) A few weeks ago I posted the following question but got no input regarding the "Lazy Susan""


"(M) If I use a "Lazy Susan" (a plate that rotates on a bearing ring) and choose one that will pass through the neck-entry of the "igloo", would it be significantly easier to rotate the vanes whether I use 1, 4 or 16 vanes ? _____"

(M) Now that I've read some more posts I am begining to doubt that I could usefully employ the 12" diameter "Lazy Susan" for my 42" dome (except perhaps if I used only one (1) vane) and I'm reluctant to do that despite the success of one builder with that approach.

(M) Am I wasting my time even considering a Lazy Susan for turning the vanes during the construction of the dome? ___

Thanks,

Ciao,

Marcel

[paulages]

the multi-vaned styrofoam board method works great, and i would reccomend it. now worries about gravity until you get that last piece in.

[arevalo53anos]

Styrofoam is a good ideia!

Hi, friends
How my pictures showed in older threads, the multi polystirene vanes (styrofoam) not only made a great work as were inexpensive and truly easy to work with.
The 1? Styrofoam board is sufficiently strong to let you to hammer the bricks to be adjusted in place.
BTW, the use of a alluminium sheet when the brick rows overcome the half height of the dome let you to do the mortar work without be worried about cleaning the inner dome.
The mortar that pass over the brick spaces is pressed against the alluminium sheet and form a thin mortar pellicle that is not a problem to worry with. Mine is there since the first fire (20-30 pizza parties and going).
And if you enjoy VPN, you could rework your Styrofoam model to a lower ellipse too!
Luis

[Marcel]

Basalt mini columns as a horizontal hide for angle iron

#13

(M) Luis, your work looks terrific. I'm at the point of laying the cooking floor. I will soon be ready to start the actual dome.

Fred di Napoli wrote in a previous post:

(F) "
I was able to find a neat tool called the "Angle-iZe! Axed Master ' at Home Depot for about $10. It comes with a CD that has programs for determing the dimensions of bricks for various types of arches."

(M) I have ordered such a template and will pick it up on Friday.
================================================== ========
(M) QUESTION: Luis, it appears that you used angle iron to support your arch entry bricks. Is that correct? ____

(M) If it is correct, then did you also put a piece of wood in a horizontal position to hide that angle iron? ___

(M) In English we call such a horizontal support a "Lintel" ("header" if in house construction). I doubt if many on this forum have seen mini Basalt rock columns but they are unusual in that they are of natural rock, very hard, and can be as long as 22".

(M) I am considering using the angle iron but adding the Baslat column as a decorative "lintel" in front.

ANSWER ____ Is this a reasonable consideration? ____

(M) Below should follow a picture of some Basalt Lintels from Turkey:

================================================== =========

(M) Luis, Paul wrote that the multi-vane approach worked well for him. You seem to agree. I will most probably use that system as well. Next follows a question about a metal "Lazy Susan". You may not know that expression in your country. It describes a plate the rotates on ball bearings.

(M) Can you answer the next question for me, Luis?



#12

(M) A few weeks ago I posted the following question but got no input regarding the "Lazy Susan""


"(M) If I use a "Lazy Susan" (a plate that rotates on a bearing ring) and choose one that will pass through the neck-entry of the "igloo", would it be significantly easier to rotate the vanes whether I use 1, 4 or 16 vanes ? _____"

(M) Now that I've read some more posts I am begining to doubt that I could usefully employ the 12" diameter "Lazy Susan" for my 42" dome (except perhaps if I used only one (1) vane) and I'm reluctant to do that despite the success of one builder with that approach.

(M) Am I wasting my time even considering a Lazy Susan for turning the vanes during the construction of the dome? ___

Thanks,

Ciao,

Marcel

[img]images/buttons/edit.gif[/img]

[arevalo53anos]

Marcel:

Thanks, my gluttony digestive apparel deserve it ?lol
Yes, I used a lintel to support the entry bricks.
No, it is not hidden. When the chimney area was constructed, the arch of this entry partially cover the lintel, still it is apparent.
I am not an expert in this matter, but I feel that if I could make the oven again I could think to build an arch as dome entry (just because two arches seem more ?elegant? for my vision).
As you are thinking to add a Basalt column as a decoration but use an structural iron lintel I am not seeing problems. Just worried as this could affect the chimney and landing area.
I decided to use the Styrofoam forms after a lot of searches of the possible methods to make a dome. I love it. Is an easy work and is plenty of opportunities to quickly change your dome shape at any time during the dome building. And the ellipse only needs a piece of chord, a pen and a cutter to be finished.
And you could use more/less than 16 vanes, just adjust to your needs. You could, even, easily construct a solid body with bonded vanes!
Then, why you are going to rotate this ?equipment?
I am suspect to said, but go with it and forget your ?friend? Susan ?lol
Have a nice work !

Luis

[Marcel]

Solid body with bonded veins.

#15

(M) Thank you Luis for your detailed reply to my questions.

(M) Although this entry is to thank Luis, anyone who feels inclined to comment I hope will contribute. ________

<snip>

Luis wrote:

(L) As you are thinking to add a Basalt column as a decoration but use an structural iron lintel I am not seeing problems. Just worried as this could affect the chimney and landing area.

(M) Do you mean the support for the chimney &/or landing areas may be weakened?

<snip>

(L) And you could use more/less than 16 vanes, just adjust to your needs. You could, even, easily construct a solid body with bonded vanes!

(M) I suspect that a solid body may be a bit difficult to break out after completion? ___

(L) Then, why you are going to rotate this ?equipment?

(M) I had hoped to use only 4 vanes so that I could see my progress. But 4 vanes would not support the bricks during construction *unless* the vanes could be moved. That was the idea of "going to rotate this ?equipment?". I had the hope that the bricks would not stick to the styrofoam but I imagine that is an unrealisitc hope? _____

(L) I am suspect to said, but go with it and forget your ?friend? Susan ?lol
Have a nice work !

(M) Luis, I may try it anyway. If the vanes stick, then I will stop trying to turn them. I only need to be aware that the added height of the "Lazy Susan" will change the height of my dome. But from what I've read by James and Jim, a higher dome (up to a point) will increase strength.

Ciao,

Marcel

Luis [img]images/buttons/quote.gif[/img]