Basalt the material made in hell.

[brickie in oz]

Basalt the material made in hell.

I am about to embark on a pull down and redo of an oven so I have started to look for materials for the new oven.

In Melbourne we have copious amounts of Bluestone (basalt) so I thought Id give it a test to see if it could withstand the immense heat generated by a wood fired oven, with the hope of using it instead of fire bricks..

So far the results are encouraging.
Lit the fire in the current oven and put in a lump of basalt at start up to replicate typical oven firings.

The basalt reached a glowing point of 760 degrees c and seemed to handle the heat ok without spalling.

The cool down will be the real test, cracking isnt the real issue, its spalling and spitting lumps of basalt into your pizza that is.

[david s]

Re: Basalt the material made in hell.

We've recently returned from France, Italy UK etc. and have seen many really old ovens in castles that had their domes made from rocks mortared together. The type of rock and the type of mortar I couldn't tell but it looked like they must have done a lot of cooking and they've held together.

[Wiley]

Re: Basalt the material made in hell.

Basalt is also known as "traprock". Do a Google search (traprock basalt wood fired ovens) and one of the entries will be my thread "Steel Dome Oven". Basalt is what I used as the heat reservoir/heat sink in my WFO. It's been used for a long long time in WFOs. Probably as good as firebrick for our applications.

I used 1/4 minus crushed basalt with calcium aluminate cement. I made up some test pieces from left over material. I suspect one could use it as a "castable" mix, but that is only a suspicion as I never bothered to do serious testing. Around here the stuff is quite inexpensive $13/yd loaded in one's trailer.

Hope this helps,
Wiley

[dmun]

Re: Basalt the material made in hell.

In Melbourne we have copious amounts of Bluestone (basalt)

In the nations divided by a common tongue department, in the states bluestone is a sedimentary rock like slate that would be entirely unsuited to use with direct flame.



I imagine basalt would work fine, being cooled lava. I can't imagine it's easy to cut.

[brickie in oz]

Re: Basalt the material made in hell.

Basalt is easier than brick to cut with a diamond saw.
Ive cut 1" deep around basalt rocks and one tap with a chisel and they slit in two.

[Lburou]

Re: Basalt the material made in hell.

Basalt the material made in hell.

I am about to embark on a pull down and redo of an oven so I have started to look for materials for the new oven.

In Melbourne we have copious amounts of Bluestone (basalt) so I thought Id give it a test to see if it could withstand the immense heat generated by a wood fired oven, with the hope of using it instead of fire bricks..

So far the results are encouraging.
Lit the fire in the current oven and put in a lump of basalt at start up to replicate typical oven firings.

The basalt reached a glowing point of 760 degrees c and seemed to handle the heat ok without spalling.

The cool down will be the real test, cracking isnt the real issue, its spalling and spitting lumps of basalt into your pizza that is.

OK, how many heat/cool cycles will you need to feel good about using it in an oven?

[brickie in oz]

Re: Basalt the material made in hell.

OK, how many heat/cool cycles will you need to feel good about using it in an oven?

Im undecided as to risk the stone in direct contact with the heat and flames as I found some small shards of stone in the oven this morning.

They might stop after a few firings, who knows?

[Nic The Landscaper]

Re: Basalt the material made in hell.

An even easier way to cut basalt is with a stone and block guillotine. In the States small hand operated ones can be cheaply rented from stone yards.

[brickie in oz]

Re: Basalt the material made in hell.

I tried my guillotine it wouldnt cut it?

[v12spirit]

Re: Basalt the material made in hell.

Basalt is also known as "traprock". Do a Google search (traprock basalt wood fired ovens) and one of the entries will be my thread "Steel Dome Oven". Basalt is what I used as the heat reservoir/heat sink in my WFO. It's been used for a long long time in WFOs. Probably as good as firebrick for our applications.

I used 1/4 minus crushed basalt with calcium aluminate cement. I made up some test pieces from left over material. I suspect one could use it as a "castable" mix, but that is only a suspicion as I never bothered to do serious testing. Around here the stuff is quite inexpensive $13/yd loaded in one's trailer.

Hope this helps,
Wiley

Hi wiley,
is constructing the whole oven with Basalt rocks better than mixing crushed basalt with concrete like you did?

[Wiley]

Re: Basalt the material made in hell.

v12spirit,
Here's a link to my first post at Forno Bravo. In that post I included a photo of an WFO built of basalt. A quick look shows large gaps between the pieces of basalt that were filled with (I suspect) common type 2 portland cement/concrete/mortar. The issue I would see with using solid pieces would be shaping the pieces to fit closely together. IMHO it is easier and more efficient to use a crushed material which one can use in a concrete which can easily be shaped and formed.

Using a smaller aggregate wherein the sand is of the same material as the larger pieces makes for a more uniform material which might lessen possible issues of unequal expansion/contraction when heating and cooling.

http://www.fornobravo.com/forum/f3/h...html#post28063

Hope this helps,
Wiley

[stonecutter]

Re: Basalt the material made in hell.

v12spirit,
Here's a link to my first post at Forno Bravo. In that post I included a photo of an WFO built of basalt. A quick look shows large gaps between the pieces of basalt that were filled with (I suspect) common type 2 portland cement/concrete/mortar. The issue I would see with using solid pieces would be shaping the pieces to fit closely together. IMHO it is easier and more efficient to use a crushed material which one can use in a concrete which can easily be shaped and formed.

Using a smaller aggregate wherein the sand is of the same material as the larger pieces makes for a more uniform material which might lessen possible issues of unequal expansion/contraction when heating and cooling.

http://www.fornobravo.com/forum/f3/h...html#post28063

Hope this helps,
Wiley

So, I see that the surround is made of stone, but is the oven itself made of Basalt? I would very much like to see any other pictures you have of this oven.

I have been in the planning stages of building an all stone oven, the obvious choice would be soapstone. After reading many research papers about thermal conductivity of stone, I am seeing that Basalt may be a viable option. As expected, using a different material comes with its own parameters, but that is the fun part...figuring out how to make it functional without it being too tedious.

I know one thing about building with Basalt from experience....it is a chisel breaking, saw blade wearing, hard lifting stone to work with.

[Wiley]

Re: Basalt the material made in hell.

Hi Stonecutter,
The photos were taken using a small pocket Kodak 110 camera and when I took them I had no idea that I would some 30 years hence be building my own WFO. As such I did not take the same photos regarding detail etc. that I would today. That being said I have looked closely at the originals and IMHO the interior of the oven was bricks as was the hearth.

The story I was told (and remember so please bear with me as this was a while ago) was that the WFO was rebuilt by the artist Paul Gauguin in return for booze money. He was depicted to me as a man of very meager means who often traded his carvings (I remember seeing a carved gunstock that I was told was traded to pay for a drinking debt, worth fortunes today but then...not so much) and worked as a day laborer for drinking money. The WFO was originally built sometime previous and had fallen in. It was built by tightly packing bricks over a sand dome and covering the bricks by basalt chips and rock so as to fill the voids between the bricks and this in turn covered by larger pieces. Whether portland type cement was used in the construction of the actual dome I do not know. When one was finished with the overfill one hand dug out the sand. I remember smoke drifting up thru the top of the structure when it was fired besides flowing out the front. No chimney. The arch was quite low/shallow. I do not know anything about whether insulation was used in the dome but suspect not.

Although the Marquesas Islands are volcanic island I do not remember seeing any pumice in my wanderings there. I spent almost 6 months in the Marquesas's in 1977, Another few weeks in 1978 and an additional almost three months in 1983. The reason I was shy a full six months and three months was I had to sail to Tahiti to renew my visas before the six and three months were up. It was a good time to be young, single and a bit adventurous.

Hope this helps,
Wiley

[Tscarborough]

Re: Basalt the material made in hell.

In that time period and area, it was almost certainly not portland cement, but natural cement, that is lime.

[v12spirit]

Re: Basalt the material made in hell.

So, I see that the surround is made of stone, but is the oven itself made of Basalt? I would very much like to see any other pictures you have of this oven.

I have been in the planning stages of building an all stone oven, the obvious choice would be soapstone. After reading many research papers about thermal conductivity of stone, I am seeing that Basalt may be a viable option. As expected, using a different material comes with its own parameters, but that is the fun part...figuring out how to make it functional without it being too tedious.

I know one thing about building with Basalt from experience....it is a chisel breaking, saw blade wearing, hard lifting stone to work with.

I am planning to build an outdoor oven and still wondering why Basalt is not used in constructing the oven itself!!