I am in the process of making my own insulating firebrick at about 1/8th the price of manufactured ones. I have the formula worked out and will be using some local Idaho fireclay for the bricks.
Currently I am building a brick press that will press the bricks to the size I want using the damp powder method. The press is base on the CINVA ram press designed for blocks used in construction in third world countries in the late 1950’s. I am resizing the chamber and adjusting the other mechanical pieces to work with the new size. When I get it all worked out and tested I will probably sell ready made plans for others who want to do it themselves.
I am currently looking at building a deairing pug mill based on the design in the Harry Davis book “The Potters Alternative“. I have to say the more I read about him the more I realize he had the same basic attitude about pottery that I do. I had been making pottery for a couple years when he started his Peru project and would have loved to have been there.
Back to the pug mill, I am going to use what is available to me and modify the design accordingly and will post my progress here. Yesterday I priced scrap metal, custom cutting and visited with an old friend who is somewhat of a “Yankee Machinist” , blacksmith and metal worker. He is 88 years old he still works in his shop every day. He said he is not up to helping build the pug mill but will allow me to use his tools (most of them he made) and give adivce. He put together the jolley arm I use based on the plans from the same book and yesterday I gave him some finished plates made with it.
It turns out there isn’t any such thing as 8″ ID thin wall pipe, Harry made his own pipe and his directions are based on that size. I can hower get 8″ OD thin wall pipe and this changes the internal diameter of the pug mill by 1/4″ and all internal parts will need to be resized. Also, I can get the pieces cut at a local steel recycling place with a plasma cutter for $100 an hour and if laid out correctly all the pieces could be cut to size in an hour. So the process begins. My reason for doing this is mainly financial, a new manufactured deairing pug mill costs in the neighborhood of $5000 and I think I can build one for a tenth that price.
Here are some pics of the order for the bookstore. These items are in the bisque stage (first firing) and will be glazed and fired again to a much higher temperature. I want to note that the only items made with the jiggering process are the plates, everything else it hand thrown on the wheel. The teapots are also part of the order but the French Butter Dishes and the Rice Bowls are not, they are just inventory pieces for the web site and the upcoming farmers market.
I took some pictures of the process and am posting them as promised. In order to carve the bats the same I use a contour tool that I purchased at Home Depot for about $8.00. It is made with a lot of small wires held in place with tension and is much more accurate that the other type available made with plastic. I also use this as a guide for making the template that goes on the jolley. I draw the contour on a piece of red oak and then draw another contour with the foot. I then cut out the template and bevel the leading edge, drilling holes to mount it on the jolley. I use wood rather than metal because I can make one quite quickly, if I find myself making tons of the same plate I can always make a steel template at a later time.
The next step is to mount the template on the jolley and set the thickness, I use a couple of Palm Pilot styli placed on the jig and then tighten the bolts (not pictured). I roll out a slab on the slab roller thicker than I want the finished piece and cut it to approximate size. It can be slightly smaller in diameter than the finished piece and will expand when compressed that way there is less waste in the jiggering process.
The finished jiggered plates setting up until they release from the plaster.  Â
The other side after being removed. They will be placed on their rims to dry.Â
Due to the large amount of table space required to dry the jiggered plates the next step in this process will be to build some racks that will allow me to work with many more plates at a time in less space. I am looking at building something between a bat rack and a ware rack that would hold the plaster bats vertical with space between each for drying and storing with shelves above to hold the jiggered plates until they set up. Once they have set up I will move them to a ware rack that I am building with about three inches between shelves. In an area about 6.25 square feet I will be able to dry anywhere from 80-120 plates (depending on size) safely and still have room in my studio to do other work. As a potter I have to wear many hats and it is time to put on the welding hat. I will make the racks with 1″ tubular steel and angle iron with plywood shelves.
I am making the saucers to go with all of the cups and thought I would describe and show the process a little. I have made a jigger using this system http://www.pspottery.com/jiggering_plate_molds.html. I cast the bats and then carve them to the shape I want using a profile or contour tool to match the shape. I am currently designing a better way to make bats for this system that will not involve carving or placing the shape in clay in the mold before casting. I will make posts showing how to do this at a later time. I only use this method for plates, everything else I do is thrown on the wheel. The arm that holds the shape for the back of the plate is called a “jolley” and the bat is called the “jigger” so the whole system is a “jolley jigger”. This system of making plates has been around for 100’s of years. I will post some pictures of the process later today or tomorrow.
Here are some pictures of the cappuccino cup and saucer in the “green†state (unfired). There will still be more shrinkage during the firings. Click on the thumbnail pictures to see a higher resolution version in a new window.
I recieved an order from a local used bookstore who is opening up a coffee house and pastry shop in conjunction with their “Fine Books” collectibles, first editions, etc.. They want 16 oz, 12 oz, 8 oz, 6 oz, and 3 oz cups and mugs with a saucer that will work with all sizes. The three largest sizes are no problem since I already make cups in those sizes but the smaller two require developing a new product. The first to be designed is the 6 oz cappuccino cups (traditional size) and I researched to see what is traditional.
