pizza oven becomes a kiln

[UtahBeehiver]

Re: pizza oven becomes a kiln

David,

Very good, I was a fine arts major then got married and had to make a living and went it Engineering, the complete opposite side of the brain. Always was hoping to get back into pottery after I retired. Would be interested in seeing some of your work.

[Greenman]

Re: pizza oven becomes a kiln

An interesting kiln can be found at Nob Creek in Byfield, it is a massive wood fired thing that must be 8 metres long (at least) and when fully fired looks like a fire breathing dragon at night. Worth a look if you are passing through Rockhampton/Yepoon way. They do some repetitive stuff but a lot of bespoke pieces.

I have an interesting pitcher that is made from the local clay that has some small stone pieces in it and it is one of those things that bring a little joy each time I spot it.

Nob Creek Pottery - How to find us

Worth a look. The rustic studio and area generally do not reflect the polished website but their work is excellent.

[david s]

Re: pizza oven becomes a kiln

David,

Very good, I was a fine arts major then got married and had to make a living and went it Engineering, the complete opposite side of the brain. Always was hoping to get back into pottery after I retired. Would be interested in seeing some of your work.

Russell,

Here are a few examples of my work.The small figures are part of a set of chess pieces based on the Gulf War.
The last pic shows how I have sealed around the flue pipe incorporating a vent to the insulation space.

Dave

I've shown you mine, now you show me yours.

[UtahBeehiver]

Re: pizza oven becomes a kiln

David,

Nice use of oxides and glazes and combining hand with wheel thrown work. So here are a few of mine. I do not have many left since I gave many away. These are circa 1970s work, abt the last time I did pottery. Everywhere I travel I away am always on the lookout for local potters I can pick a piece to add to my collection.

[Les]

Re: pizza oven becomes a kiln

There was a member on this forum (haven't heard from him in a while) but he was doing some pretty cool stuff related to us. Check out link #17

http://www.fornobravo.com/forum/f35/pieceapizzapiepottery-input-requested-1971.html

[UtahBeehiver]

Re: pizza oven becomes a kiln

Thanks for the ceramic pizza slice link Les, my pottery interest was a love for the arts, sadly I found I could not support a family on it so I became an Engineer with an artistic flair!!!! Still 40 years later I appreciate good pottery.

[david s]

Re: pizza oven becomes a kiln

David,

Nice use of oxides and glazes and combining hand with wheel thrown work. So here are a few of mine. I do not have many left since I gave many away. These are circa 1970s work, abt the last time I did pottery. Everywhere I travel I away am always on the lookout for local potters I can pick a piece to add to my collection.

Nice work Russell. We also buy the odd piece on our travels. We're taking the first two weeks of Jan to ski in Japan and also to visit Kyoto, will pick up some pots there.

Les those pizza slices look interesting, very crunchy.

[david s]

Re: pizza oven becomes a kiln

Did a little more on the kiln (first coat of render), before we leave for Japan, primarily to ski, but have also arranged to visit a ceramic artist potter in Kyoto too, should be fun, can"t wait to get away from this oppressive tropical heat.
Plan to reduce the intake port area for hopefully, more efficiency.

[UtahBeehiver]

Re: pizza oven becomes a kiln

Almost there, are you going to do some test bisque fires first? I was the kiln tender, so got to stay up all hours of the night tending the kiln. Best part though was I loaded the kiln and my pieces went in the prime areas of the kiln . Have fun skiing in Japan, you will have to come to Utah sometime and ski of the best powder in the world.

[david s]

Re: pizza oven becomes a kiln

I have done one bisque firing with only four things in the kiln. It should fire better when fully loaded,but that will have to wait until we get back.
Japan powder pretty perfect for me, the snow is so dry you can't make a snowball properly. Their snow comes from Siberia. For us it's only a seven hour flight almost due north so only one hour time difference, but the legendary Utah sounds amazing too.

[david s]

Re: pizza oven becomes a kiln

Finally got around to finishing the kiln. I fitted it with a double stainless flue (inside 5" diam outside 6" diam) Pics show burner set up, pyrometer and door panels sealed up.
I still wanted to proceed really slowly (100 C/Hr) as it was a bisque firing and render coatings only finished about a month ago. The firing took ten and a half hours to reach 1040 C. and performed extremely well, using less than a 9Kg bottle of gas. Have yet to weigh the bottle to make final calculation of gas consumption. May make some minor adjustments to intake port diam. and burner position in relation to port.
I'm a bit embarrassed about how long this has taken, but the truth is that I don't really need it as the few pieces that I need to fire on an ongoing basis I can get fired elsewhere.

[david s]

Re: pizza oven becomes a kiln

I weighed my now finally empty gas bottle and have calculated that the kiln used 6.5kg of gas to fire to 1040 C
In $AU that is $17.60 I'm reasonably happy.

[v12spirit]

Re: pizza oven becomes a kiln

Congratulations on finishing the 7th kiln and the efficient performance achieved. Glad to hear about the economic fuel consumption.
Questions:
1- why were you seeking a lightweight castable? And what is the "rice" in your brew?? And what is the advantage of crushed firebricks over sand in that brew?
2- I'm new actually to the downdraft design, but do you fire the kiln with the door panels tightly sealed? Wondering about the way the kiln is vented and how air circulates if so..
3- could you tell about the performance adjustments you have done if any?
4- are the rest of the kilns gas fired and are they that efficient in fuel?
5- is the downdraft design what allows the kiln to reach that temperature? And is there anything special in your brew to withstand that heat and can it be applied for pizza ovens?

[david s]

Re: pizza oven becomes a kiln

Congratulations on finishing the 7th kiln and the efficient performance achieved. Glad to hear about the economic fuel consumption.
Questions:
1- why were you seeking a lightweight castable? And what is the "rice" in your brew?? And what is the advantage of crushed firebricks over sand in that brew?
2- I'm new actually to the downdraft design, but do you fire the kiln with the door panels tightly sealed? Wondering about the way the kiln is vented and how air circulates if so..
3- could you tell about the performance adjustments you have done if any?
4- are the rest of the kilns gas fired and are they that efficient in fuel?
5- is the downdraft design what allows the kiln to reach that temperature? And is there anything special in your brew to withstand that heat and can it be applied for pizza ovens?

1. When firing a kiln energy is expended in heating thermal mass. The wares, props and shelves inside the kiln are the thermal mass, so it's a waste of energy having floor and walls made of a high density refractory. Most modern kilns are made with IFB's for the floor and a hot-face ceramic blanket for the ceiling and walls.I did not use rice in my brew, but I did try using it in some earlier tests and found it unsatisfactory. I used 50/50, by volume, rice and castable refractory, also tried the same thing with sawdust. The idea is that they burn away and you are left with air spaces. Neither was satisfactory and left me with a crumbly product once dry. Crushed insulating firebrick 50/50 worked pretty well though so I went with that.The advantage of crushed firebrick over sand is that it will withstand the high temperature, whereas sand can have a tendency to turn into glass in the presence of fluxes at high temperatures. This is not an issue with an oven because we don't get the temperature anywhere near those of a kiln.
2.yes the kiln is fired with the door completely sealed.
3.I have adjusted the intake port to restrict the inflow of air. I can also restrict the airflow by the sliding damper at the base of the flue.
4. All the kilns I have built were fired with gas except one wood fired kiln. efficiency is very dependent on the material used. A dense brick kiln probably has hundreds of times more thermal mass than the wares contained in a firing, hence fuel consumption is very high.IFB's are much better and ceramic blanket better again. I have built kilns using mud brick, solid red house bricks, dense firebricks, IFB's and now this cast one.the lighter the material the better the fuel economy.
5. Yes, nearly all stoneware (1200 C+) kilns are downdraft, it utilizes all of the flame. Also being able to control the chamber atmosphere is what also helps achieve higher temperatures. A small simple updraft kiln I made many years ago, for ceramic jewelery, from dense firebrick was woefully inefficient, but being so small it didn't really matter.
Yes there are plenty of things in my brew that allow it to be serviceable for higher temperatures, but most of these are simply not required for an oven that only goes to around 500 C.

[v12spirit]

Re: pizza oven becomes a kiln

Thanks for the details. So did using crushed firebricks make the brew noticeably lighter? or you were making a compromise of weight reduction versus strength so that you eventually chose 35 mm walls?