Thursday, July 31, 2008
Tuesday, July 29, 2008
Before the flood of 2008 this was a nice concrete slab about 10 feet by 20 feet. After an hour and a half of shoveling, in 90 degree heat, I uncovered the now unlevel and cracked slab.
I was hoping to start laying cinder block and fire brick as soon as I unearthed the slab--Surprise, Surprise! Now I have to level the pad and I'm not sure how to do it. Should I use sand, should I use dirt, gravel? Best source to get this question answered, or at least get some great advice, is WoodKiln on Google Groups. This is a fantastic site for people interested in wood fired ceramics.
I came across this group by accident and joined the same day. After posting an introduction to the group I also asked for some advice about the kiln I was building and questions about the firebrick I wanted to use. Within a day several people welcomed me to the group and I had a lot of great information about my kiln and the firebrick I planned on using.
I was also steered to a site called The Potters Shop which is a great site for books on pottery. I was told to get the book "Laid Back Wood Firing" written by Steve Harrison. In this book he has the plans and how to's about building and firing the kiln that I am planning on building. I plan on ordering the book today and can't wait to start reading it.
Friday, July 25, 2008
Thursday, July 24, 2008
Front wall measurements are 36 inches wide by 25 inches tall. The interior of the firebox is 27 inches wide and I'm thinking of making it 22.5 inches deep.
Of the many diagrams of this type of firebox, most of them show the firebox door just above the mouse hole. For this kiln I am going to put it on the side of the firebox.
As for the firebox lid I was thinking about just using kiln shelves and kaowool fiber but now I'm thinking about using a cast iron hinged door from an old furnace. I'm not sure how I'll do it yet but I'd like to glue or attach soft insulated firebrick to the underside of the door. I think I'm also going to use 3/4 inch rebar rods instead of the hobs to hold up the wood.
I'm not sure what I'm going to do about the throat arch yet. I suppose the best route to go is use arch brick and then some castable refractory to square it off. But that costs money. Will have to ask some questions but I'm wondering if an arch is a neccesity. Maybey I can just use my standard bricks and build a square opening.
I'll be using Low Duty Hard Fire Brick that measure 9 inches by 4.5 inches by 2.5 inches. These are relatively inexpensive and I can buy them locally at a building supply company. Only problem is they only sell full brick and split brick. I'll pick up about 150 more brick next week so I can finish the fire box.
If all goes well I'll get the rest of my firebrick next week and finish the firebox on the weekend.
Tuesday, July 22, 2008
Yes, from this small pile of bricks I'm building a small wood-fired kiln. In this pile is approximately 50 hard fire brick, 75 red common brick, and some pavers and some other crappy brick I can't use.
I am still short of materials though. I need 8 cinderblock, which I am going to use as a base to build the kiln on. Bringing the kiln up off the ground makes stoking the kiln easier on the back and knees. Also I've been told that the kiln will heat up faster, as the ground won't be sucking up all the heat.
I also need some sort of smoke stack which I am going to use as a chimney. I am thinking about a 4-foot section of cast iron pipe which will be inserted into a square sleeve of red common brick. It would also be nice to buy about 20 more hard fire brick. I can buy them locally for $1.39 per brick.
Other materials I have on hand that I'll be using are 10 insulated soft brick, some kiln shelves for the top of the kiln, and some kaowool fiber.
I'm building this in back of my studio on a concrete slab. The area is covered with a coregated tin roof. The 6-inch layer of mud and sand is a gift from the flood which I haven't yet shoveled and hauled away yet.
Stay tuned for pictures of the evolving kiln.
Thursday, July 17, 2008
"Wood-fired Ceramics, Contemporary Practices" by Coll Minogue and Robert Sanderson. Here is an excerpt from the inside cover. "In Wood-fired Ceramics, Coll Minogue and Robert Sanderson briefly describe the development of the main types of wood-fired kilns used by today's potters. They then present the aesthetic aims, working practices and kilns of an international group of artists. Kiln-firing logs, clay, glaze and slip recipes, and kiln plans are also included. The work by over 60 artists, which illustrates the text, is representative of the diversity of styles in contemporary wood-fired ceramics. An Awesome book.
Anyway, I gotta build one of the kilns illustrated in this book. It is called a "long throat Bourry kiln" . Sandy Lockwood uses one and hers is based on a design by Stephan Harrison. The link I'm posting is actually Andrew Stewart's kiln but good photos of this type of kiln. I need to get some brick so I can start building.
Another book I recieved is "Ceramics of Picasso" by Georges Ramie. I've never been a big fan of Picasso's paintings but I'm really impressed by his pottery. Maybey I just think his artwork is better suited for pottery rather than canvas. Anyway, this book has 223 fantastic color illustrations.
Another neat item I came across is a product called Cerafiber Wet Pack. This might have a lot of kiln building and kiln repair applications. My friend John works with furnaces and boilers and he is the one who suggested it. It is a needled refractory fiber blanket that is packaged in a moist form. The flexible sheets can be easily cut and can be custom molded in complex shapes to a required size, shape and thickness. When the product dries, a hard rigid surface is created. Its refractory limit is 2400F. I contacted a company in Milwaukee, Wisconsin named Fire Brick Engineers Co. Price is $44.00 for a 2 foot by 3 foot sheet, one inch thick. Seems a bit spendy but it might have a lot of applications. When I get some extra money I'm going to have to get some and see what I can do with it. Better get going. Will try to post some more Raku glaze recipes tomorrow.
Tuesday, July 15, 2008
Alkaline Blue Raku Glaze
Frit 3110 70
Gerstley Borate 5
Soda Ash 10
Copper Carbonate 3
Friday, July 11, 2008
I'm pretty excited about this new kiln building experiment. My original Raku Wood Burning Kiln, based on Nesrin Durin's design, was loosely assembled (and I mean LOOSELY). I'm going to tighten everything up and change it into a downdraft kiln consisting of four main components--the firebox, the stack area, the damper, and the chimney.
If all goes according to plan here is how it is going to work. Wood is stoked into the firebox through the stoke hole and placed on a grate to burn. The flame and heat will naturally rise and circulate throughout the interior of the kiln. The construction of this type of kiln will force the flame back downward to be exhausted at the bottom of the kiln and up through chimney, which in my case is a piece of stove pipe about 4-5 feet tall. A mix of firebrick and red common brick will be used to construct the main part of the kiln.
I'm going to load my pots from the top opening of the kiln onto the kiln shelf, and then use kiln shelves to seal up the top. I'm also going to use a piece of kiln shelf, as a makeshift door, to seal up the stoke hole when I'm not adding fuel to the fire.
I haven't thought about peek holes yet, and pyrometers cost money. So.... I'll just wait and see how things go.
Thursday, July 10, 2008
Wednesday, July 09, 2008
Beads Raku Glaze Recipe
Magnesium Carbonate 31.25
Gerstley Borate 31.25
Black Widow Raku Glaze Recipe
Gerstley Borate 80
Nepheline Syenite 20
Black Copper Oxide 71.7