FrancescoAletheia Posted November 1, 2014 Report Share Posted November 1, 2014 Hi, Im Francesco and I im love with this site! I am a graduated sculptor, i studied at the Academy of Fine Arts in Sicily and i am wandering around the pottery world since one year... I usually fire my figurative sculptures in an electric kiln of a friend of mine and obviously im really satisfied about the quality of the final pieces. However im thinking about going to the next step and start to fire my own pieces. It would be a enormous joy to follow them from the beginning to the end and to be in control of the procedure. To start i was thinking about something like this: http://3.bp.blogspot.com/_d0wnvWS1pnY/TGOBogYPuBI/AAAAAAAAAo0/Sy7RM9z_aKc/s1600/002.JPG I think its perfect for my "bozzetti" and "modelli", it s very easy to build and cheap too! My only dilemma is: what kind of gas tank will i need? How many liters of propane/butane do i need for a good terracotta firing? In Italy the retailers standardised your options: 10 liters, 15 liters, 25 liters. What do you suggest? Thank you in advance! Link to comment Share on other sites More sharing options...
oldlady Posted November 1, 2014 Report Share Posted November 1, 2014 hello, and welcome. the picture you sent is of a raku kiln. are you planning to use it for raku? if so, you might want to put a metal lid with a sturdy handle on the top so the kiln can be easily and safely lifted off the pots when they are ready to be reduced. Link to comment Share on other sites More sharing options...
Benzine Posted November 1, 2014 Report Share Posted November 1, 2014 I have a similar style kiln, I use for Raku firing. They are relatively cheap and easy to build. As Old Lady asked, is Raku, what you intend to use it for? Such a kiln isn't efficient for anything else, as they don't retain heat well at all. So a standard glaze firing would burn through a lot of gas, literally. A bisque firing would be almost out of the question. If you are interested in Raku, there are a lot of knowledgeable posters here, including Marcia, who is the Empress of Raku... Or what ever title she prefers... Link to comment Share on other sites More sharing options...
bciskepottery Posted November 1, 2014 Report Share Posted November 1, 2014 What would be helpful is knowing what firing temperature you use for your sculpture, whether you fire it with or without glaze, whether it is for indoors or outdoors, type of clay and firing range of the clay, etc. The kiln you sent the link to could work, or it could not . . . but it is hard to say without knowing the other information that is missing. And, for the kiln pictured, you could use a single tank (some use the size folks use for a bar-b-que grill other use larger tanks depending on number of pieces to be fired, length of firing, etc.) or multiple tanks "daisy-chained" together. Link to comment Share on other sites More sharing options...
FrancescoAletheia Posted November 1, 2014 Author Report Share Posted November 1, 2014 You re right, that is for raku firing. I thought it was good for clayfire (terracotta) too. Usually i fired it a little below 1000° Celsius. I dreamed of firing two pieces together, i d want to build something like that, but with only two holes, one for the burner at the bottom and one for the smoke at the the top of the lid. Id want to use a barrel instead of the wire fencing; if you tell me it will reduce the heat loss, i ll double the amount of fiber blanket. Why it is not good for terracotta? What do you propose? Link to comment Share on other sites More sharing options...
Benzine Posted November 1, 2014 Report Share Posted November 1, 2014 Raku kilns, are just not efficient for standard firings. They are designed to heat and cool quickly, so the insulation only has to be good enough to retain that heat for a short amount of time. Standard kilns are made to hold the heat over a longer time period. If you do plan to use this as a primary kiln, I would recommend finding an old electric kiln and converting it to fire with gas. There are a lot of old, unwanted kilns out there. In many cases, people are happy to let you have them. And there are plenty of resources that show you how to both convert and fire such a kiln. For the Raku process, you need a clay that can withstand thermal show. Usually any mid to high fire groggy clay will work. I've never used terra cotta, but I don't believe it would work. Link to comment Share on other sites More sharing options...
FrancescoAletheia Posted November 1, 2014 Author Report Share Posted November 1, 2014 Ok i get it! You re right, i think there are tons of old electric kiln out there ready to be "converted". I will start my research as soon as possible and i will let you know. Now i think i understand what kind of kilni need for terracotta, only one question remains: how many liters of propane will i need for firing? I would like to find one of the size of the picture that i posted here, something like this: 1 x 0,80 x 0,50 meter. Link to comment Share on other sites More sharing options...
Benzine Posted November 1, 2014 Report Share Posted November 1, 2014 The tank I used, is just a twenty pound tank, like you'd use on a gas grill. It lasts me several firings. For something that takes longer, you'd probably want a hundred pound tank, or at least several smaller tanks chained together. Link to comment Share on other sites More sharing options...
FrancescoAletheia Posted November 1, 2014 Author Report Share Posted November 1, 2014 Okay first time i ll buy the 25 kg tank (55 pounds) just to be safe. Considering im a newbie, i will need a thermometer too, i dont have the "temperature eye" yet, but its the first skill id love to acquire! Any other suggestion? Do you think that an old converted electric kiln + gas propane is the cheapest way of firing? Link to comment Share on other sites More sharing options...
Benzine Posted November 1, 2014 Report Share Posted November 1, 2014 I can't say propane is the cheapest, especially with fluctuating costs. Electric is cheap and easy. But if you want to go gas, propane is good. In terms of figuring the temp, you'll want a thermocouple and pyrometer, and some Cones. The Cones will be a must, if you are doing traditional firings, and will need to figure out, if things are receiving the appropriate amount of heat, over a period of time (heat work). Link to comment Share on other sites More sharing options...
FrancescoAletheia Posted November 1, 2014 Author Report Share Posted November 1, 2014 I think i have some translation issue... what is a cone? Do you think it is cheapest to do with an electric kiln? Normally what is the electric cost for you for every single terracotta firing? Link to comment Share on other sites More sharing options...
Benzine Posted November 1, 2014 Report Share Posted November 1, 2014 No translation issue. A Cone refers to a pyrometric cone. It's what ceramicists use to monitor their kiln temperature. They look like this They are manufactured item, that is designed to melt and bend over, once they've received the appropriate amount of heat work. The diagram above shows the standard set up. You have multiple cones. One that melts before your final temp, one that melts at your temp, and finally, one that melts above your temp. That way you know if the kiln over or under fires. Some electric kilns have "Cone Sitters". It's a device, where you set your firing cone, and when it melts, it shuts off the kiln. I know electric is really efficient, which is one reason a lot of potters use it. Is it the cheapest? I don't know enough to say for sure. I'm also no expert on total firing cost. I do no, especially for low fire, it's nothing much at all. There are more knowledgeable people than myself here. I'll let them comment. Link to comment Share on other sites More sharing options...
oldlady Posted November 2, 2014 Report Share Posted November 2, 2014 francesco, what country are you living in and is it where you plan to build your kiln? Link to comment Share on other sites More sharing options...
FrancescoAletheia Posted November 2, 2014 Author Report Share Posted November 2, 2014 Thank you for the cones lesson, i met this kind of device only once in my life during a lost wax casting. I live and work in Italy. Link to comment Share on other sites More sharing options...
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