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[jcdup]

Rotating the vanes

Hi Marcel,

I built my oven using two vanes which I rotated to get the angle of the lower bricks correct. Only near the top did I actually use them to support the bricks.

I did not try to, but I do not think that you will be able to rotate the vanes at all if once you use them to support the bricks, regardless of whether you use the Lazy Suzan or not. The bricks resting on the styrofoam creates quite a bit of friction which, in my opinion, makes rotating difficult, if not impossible.

I think that If you want to use the vanes to support your bricks at the lower levels, you will have to leave the vanes static and not rotate them. For this a larger number of vanes will work better.

Hope this helps.

Johann

[Marcel]

Lazy Susan is "no simpler"

#18

(M) Thank you, Johann, for your input. It supports my intuition and suggests my impulse to use a Lazy Susan would indeed be an exercise in futility.

(M) Johann, I would like to see images of your work. Do you have postings on this forum? ________

Ciao,

Marcel

[arevalo53anos]

Marcel:

I learn too much from this group and I borrow many of the ideas and solutions by others used/developed.
I am so grateful to all that I am the person that needs to said thanks.
Regarding your first question I mean that you have the dome built with refractory brick and mortar with similar characteristics. The entry has an iron lintel that has a different temperature/dilatation coefficient, as has the Basalt column. The chimney area is normally made with common bricks which have another temperature coefficient. And this three different ?systems? need to be concatenated just at the entry level (when the fire is growing, you have nearly the highest temperatures there).
In using only a lintel, this is rested over the two ?soldier? columns and opened at the sides. The row of refractory bricks over it is self supported (horizontally) since is a sphere/dome row, allowing some movements of the lintel.
You need to think how will be your Basalt arrangement with and without lintel to have minimum problems with dilatation.

Styrofoam. You could said to your dog that his bone is hidden in the center of the dome, he will take count of the work! Lol. May be he will come a pizza fanatic too!!!

I am with Johann comments. When I work with the 16 vanes model, I used a hammer to make the necessary adjusts to complete the rows. By friction/contact will be hard to rotate the vanes after two or three rows (when the bricks are arranged in angle).

Higher dome increments strength until the perfect sphere (semi-sphere) that is when the forces are equally distributed.
Thinking in construct a new dome, it is possible that I would to do it lower than I have now (today approximately 40? diameter 18? high). More VPN style. Even is ok like it is.

Luis

[Marcel]

"concatenated" is a Sunday word ;-)

#19

(M) Dear Luis,

It is always a special pleasure to read the posts of this forum's members from other countries. They have such special, charming ways of phrasing things yet they almost always get their messages across as intended. You have outdone yourself though with the use of "concatenated". That is a word I needed to look up!

(M) I am not intent on using the Basalt Lintel "Come Hell or High Water". But I thought it might be a possibility. You seem to have some concern about it's coefficient of expansion in relation to other dissimilar materials.

(M) You are not expected to reply to this post, though your input, or that of other members, is always welcome. But I probably have not thought this through very carefully so I should try to clarify: The Basalt column would be in conjunction with a steel angle iron. It is strictly an aesthetic device, though because of it's strength it could also be structural. I simply wanted to hide the angle iron in an attractive way. But if you &/or others tell me that this is too problematic, I will give it up along with my girl friend, Lazy Susan. ;-)
Besides, I would like to try an arch, especially if I can find, or make, rounded edge bricks! Then there would be no iron, and no Basalt lintel.

(M) Luis, you wrote, in part:

(L) "Styrofoam. You could said to your dog that his bone is hidden in the center of the dome, he will take count of the work! Lol. May be he will come a pizza fanatic too!!!"

(M) I am sorry to say that I missed your joke :-( Perhaps you were thinking that I like hot dogs?

(M) But your suggestion of hiding something in the dome brought to mind a story that a friend relayed to me this morning about "Il Duomo" , a famous dome in Italy:

(M) The story goes that the city fathers were wondering how to support this huge dome during construction. One suggestion was that they pack tons of raw sand as a support. The added element was to be pieces of gold! The pieces of gold were to provide an incentive for the villagers to empty the sand while looking for the gold. They gave up on the idea. I would, too. If you've poured sand at the beach you know it forms a ^ not a hemisphere.

(M) What is "VPN style"?

Ciao,

Marcel

[paulages]

i had a french roomate for a while, and he was constantly using english words i had bever heard of. same with an old german friend. i read quite a bit, too. says something about our education system maybe? ...or maybe just that concatenated is just too hard to say.

marcel,
if you are thinking of using a lintel, why use angle iron at all? wouldn't a lintel do the job structurally by itself? by the way, i believe my brick supplier here in portland has solid refractory lintels. wouldn't look as nice as basalt, and you wouldn't be able to say that your oven contains a piece of the cascade range, but it sure would work nicely.

[Marcel]

"A Piece of the Cascade Range"

#20

(M) Paul wrote:

(P) " marcel,
if you are thinking of using a lintel, why use angle iron at all?

(M) Why, indeed?

(P) wouldn't a lintel do the job structurally by itself?

(M) Dunno; I never arm wrestled a lintel.

(P) by the way, i believe my brick supplier here in portland has solid refractory lintels. wouldn't look as nice as basalt, and you wouldn't be able to say that your oven contains a piece of the cascade range, but it sure would work nicely.

(M) Plus it would give me an opportunity to see if you had started on your roof yet ;-)

Concatenatedly Yours,

Marcel

[jcdup]

Hi Marcel,

(M) Johann, I would like to see images of your work. Do you have postings on this forum?

Yes. My oven's photos are under the thread "Pompeii oven in South Africa" in the Brick Oven Photos (http://www.fornobravo.com/forum/showthread.php?t=220)

Cheers

Johann

[dmun]

Linear expansion of materials

From Machinery's Handbook 20th edition:

Values are per unit, per degree F:

Wrought iron:
.00000661

Cast iron:
.00000655

(no value given for Stainless Steel)

Granite (and presumably other ignious stones like basalt):
.0000044

Concrete:
.0000080

Brick:
.0000030

Slate:
.0000058

Sandstone:
.0000065

Pine:
.0000028

What do we learn from this? If mortar expands more than twice as much as the bricks it holds together it's no wonder that masonry walls fall apart. On the other hand, there's still a bunch standing from the time of the Romans.

My guess is that freezing water in wet masonry is the cause of most masonry failure.

[tdibratt]

Styrofoam Vanes - Good Idea

I can speak to Paul's vane idea as well. I used it and had about 6-8 of them. It worked great. Since I did not have the entire hearth covered I was able to rotate the vanes silightly left or right as I set my bricks and used my fingers to smooth out any mortar that may have entered into the underside of the dome. When I was done, there wasn't much cleaning or pointing to do.

Regards

[Marcel]

There's "brick" and "firebrick"

#21

(M) David wrote:

(D) "What do we learn from this? If mortar expands more than twice as much as the bricks it holds together it's no wonder that masonry walls fall apart. On the other hand, there's still a bunch standing from the time of the Romans.

(D) My guess is that freezing water in wet masonry is the cause of most masonry failure."

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

(M) What else we learn from this is the importance of using mortar with the closest coefficient of expansion to that of the material it bonds, i.e., refractory mortar.

(M) I suspect that in the time of the Romans there were no firebricks with precise % of Alumina and Silica. I also suspect that even their "normal" non heated masonry walls were made of brick that was probably more porous and consequently less strong than the bricks of today.

(M) I agree with David's guess that freezing water in wet masonry is the cause of most masonry failure but to support our guess we'd have to try to eliminate the material variables and then compare the failure rates of masonry used in equatorial South America with that in frost zones. This would have to exclude "dry fit" masonry, of course. It would probably be a very unreliable study since the materials are so different as well as the ages of the masonry work. Enough!

[paulages]

what's the expansion rate of a pot of lentils? and marcel, i don't know if we're close enough yet to be concetenated.

[Marcel]

Collapse of the Forum

#22

(M) Paul wrought:

(P) "what's the expansion rate of a pot of lentils?"

(M) What's the expansion rate of pot?

(M) "Collapse of the Forum"

Chow,

Marcel

[paulages]

lentils really expand your mind, man...

and now back to the scheduled program.

[Robert Musa]

What do we learn from this? If mortar expands more than twice as much as the bricks it holds together it's no wonder that masonry walls fall apart. On the other hand, there's still a bunch standing from the time of the Romans.

My guess is that freezing water in wet masonry is the cause of most masonry failure.

imho, the mortar really doesn't contribute much to holding the oven together. gravity, on the other hand, doesn't change with the temps we are talking about. from a practical standpoint i think we are really talking about bricks slipping into the oven (they'll never slip outward).

the downward and lateral pressure of the bricks above and adjacent, in most cases will be sufficient (barring volcano or earthquake) to hold the brick in place. i think its interesting that if for one reason or another a brick is no longer subject to the downward and lateral pressures of its neighbor bricks, because of shifting bricks or crumbling of mortar then, at that point, the brick is no longer contributing to the overall structural stability of the dome. or to put it another way, the bricks with the greatest likelihood of slipping into the chamber are those bricks which are contributing least to the structural stability of the dome. i take comfort in this thought.

as i was placing the top courses of bricks on my oven, it was fairly clear as to which bricks were going to be potential problem children. they'll try to slip in as you lay them. those bricks, i cut into a squat pie shape to eliminate any chance of slipping in.

[arevalo53anos]

Friends/Marcel:

Luckily, you are in a great group, which use your birth language (or, at least the one that you are habituate to).
The other countries members have his ?charming?, but his headache too? 8>}
My birth language is Spanish, living in a Portuguese language city and my work forces me to understand French, Italian and English, of course.
Let?s your imagination flight and think in translate BTW, IMHO, AKA or simply bro (from brother). And ours is Latin root, not Germanic one, auch! Thanks God we have Sony and WB by here. Or then, VPN (that in Italian language means Vera Pizza Napoletana!!!)
Ok, sorry because I use an old/not normally used word, I just try to be as clear as possible (and the opposite was obtained) (Murphy, perhaps?).
And even you do not catch the dog joke!!! I tried to say that the Styrofoam is too easy to work as it is to break. You could remove it from the dome using your fingers (or your dog fore-foots). By static charges, the dog will look as a snow ball! Lol
The VPN style is a kind of pizza (and pizza certificate too) that do not permit other thing that flour, water and yeast in his dough, is cooked in high temperature ovens and has little topping. (You could google)
I hope this message do not carry concatenated problems at this time.

Luis