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masuzzu 10-06-2008 05:28 PM

moist clay
 
Does anyone have any knoweledge or experience with moist clay(available at art suplies). Can it be used to level bricks or as brick mortar?
according to the info on the label ,clay withstands 1200 degrees.
Thanks in advance!

nissanneill 10-07-2008 02:14 AM

Re: moist clay
 
masuzzu,
you would be much better off to use a dry fine sand or fireclay to level and bed in your hearth bricks rather than a wet sticky clay. Even using fine (portland cement consistency) fireclay to level my bricks, it required patience and determination to get them right. Trying to do this with a stiff clay would almost be impossible.
Whatever you use will add a little to your thermal mass.

Neill

dmun 10-07-2008 03:32 AM

Re: moist clay
 
Frances built her oven with fireclay based mortar (no portland). It seemed to work out fine. It may not be strong enough to build self supporting arches, but for the mortar for the dome it's a proven method.

Fireclay has some refractory properties. It's also cheaper than clays used in pottery, particularly prepared wet clays.

Wood fired oven workshops 10-07-2008 06:34 AM

Re: moist clay
 
Hi Mazussa,
I've been using clay for kilns, and more recently for ovens, for the last 40 years and you should not dismiss the refractory properties of this abundant material.
The secret is to not have too much 'plastic' clay in the mix.
In my workshops we build satisfactory, and perfectly working ovens, from equal parts of plastic clay, sand, and stone dust with perhaps the addition of 5% cement.
My former university students [ANU] built numerous kilns with such a mix and wood fired stoneware and porcelain ceramics to 1300 degrees centigrade with great success.
As a binder for bricks there is no trouble at the low temperaturers of, say 700 degrees C, and the mix is successful as a stand alone dome for a wood fired oven.
You may like to see a short video of building a 'clay' oven on www.au.lifestyle.yahoo.com/better-homes-gardens then click on DIY and go to the 3rd page where you will see a photo of an oven.
Be aware that there is an enormous difference in clays and something labelled as 'Fireclay' may be satisfactory in bonding bricks together but hopeless when it comes to binding a mix for forming a dome.
I use, and urge my workshop participants to dig their own, natural clay [see test on the Better Homes and Garden web site pattern sheet] rather than buy prepared bagged clay.
I'm sure the manufacturers would have a heart attack to see you adding aggregrates that they have taken the trouble to remove, at some expense.
Natural clay mixes have been used for centuries as oven building material and in my country, Australia, termites nests have been 'reconstituted' to build, perfectly satisfactory, pioneer bread ovens.
The ants have a mix of clay and aggregrate about perfect for an oven.
The only consideration in making an adobe, or clay based oven, is that it is not weather proof and needs to be protected from the elements.
Other than that if the proportions are the same it performs very much like its high tech, equivalent.

jengineer 10-07-2008 09:45 AM

Re: moist clay
 
Link above will not work go to my next post to get the corect link

stevepreece 10-08-2008 03:19 PM

Re: moist clay
 
I had issues getting to it too.
You need to to surf to it.
go to yahoo austarlia.... dot com dot au (sorry can't post links)
then use the menus to get there as below
"lifestyle"
scroll down and select "better homes and gardens" from the big green "YAHOO!7 LIFESTYLE:" box

do a search for "oven". There are two ovens there one is brick others is clay.

Hope that helps.

jengineer 10-08-2008 03:34 PM

Re: moist clay Missing links
 
here are the links for those interested...

Pattern Sheet Pattern Sheet
As for this design we would recommend that you modify the entrance way to get the vent outside of the dome, bring it forward.

Pizza oven ala Alan Scott 2004
Yikes this one is old and I am sure that it has already been posted on either this site or the earlier yahoo version of FB - that dates me.

dmun 10-08-2008 03:55 PM

Re: moist clay
 
Oh Good Lord, not this again:

Quote:

Lay a bed of decomposed granite (what we would call stone dust) to the level of the top of the blocks. Pack this down well until this is hard. Avoid using sand because it tends to shift and not pack down well. The function of the thick bed is to absorb the heat while the oven is heating up, and returns the heat to the oven once the fire is out... Once the granite has been packed tightly into the well, spread and level a 10-15mm thick layer of brickie's sand over the surface as a level bed for the oven floor...
Not a TRACE of insulation under the floor. You can forget about pizza with this thing. And isn't Australia an arid country without vast forests to combust? Wood must be scarce and expensive.

And this mess was on Television, so many will take it as gospel.

And the flue in the dome? Don't get me started. Don't even bother to download this PDF.

asudavew 10-08-2008 04:44 PM

Re: moist clay
 
Quote:

Originally Posted by dmun (Post 42404)
Oh Good Lord, not this again:



Not a TRACE of insulation under the floor. You can forget about pizza with this thing. And isn't Australia an arid country without vast forests to combust? Wood must be scarce and expensive.

And this mess was on Television, so many will take it as gospel.

And the flue in the dome? Don't get me started. Don't even bother to download this PDF.

You should be used it by now! ;) Hopefully the faithful and determined know better! ( And the people who actually read through the plans and this site.)

Wood fired oven workshops 10-08-2008 08:10 PM

Re: moist clay
 
Perhaps dmun would be not be so adamant if he could see the quality of the pizzas [and breads and roasts] that the 'mess' produces.
t is true there is no insulation immediately under the floor tiles - it is 200mm below a 'heat bank', effectively making the floor 240mm. thick. And that's the intention - to retain adequate heat within the 'floor' for long, sometimes overnight roasts and casseroles.
Exit gases are controlled by a metal slide over the chimney which acts as a damper, giving fine heat control.
This low tech. oven is one of 2 ovens built during the workshop - the other being a conventional, quality refractory structure of castable or brick.
It gives participants the experience of building two ovens at the cost extremities [with the low tech. oven costing next to nothing] and numerous participants have gone on to build their own and are totally satisfied.
Oh, and it uses very little timber to heat it up.


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