bny got a reaction from yappystudent in Using Small "Test" Kilns as Only Kiln
I have two of the Paragon Caldera kilns with Orton digital controllers.
They will run on a standard household circuit. It would be better to have a dedicated circuit installed with the most heaviest gauge copper wiring allowed by code. I tried running mine on an outdoor patio outlet distant from the panel, but this did not work well. Any energy that is not being dissipated inside the kiln, is being dissipated by the house wiring, and who knows how hot that is getting. I now run it on a garage outlet, which is the closest outlet to the panel. It will not run well on even the heaviest gauge extension cord; it must be plugged directly into the outlet.
If you are having a new circuit installed, it might as well be 220V, which gives you a wider choice of kilns for cone 10.
I am partially satisfied with these Paragon units with one notable exception: mine will make 2300 F only for around 6 firings. Both degraded to be reluctant to make even 2200 F in any reasonable amount of time. I replaced the elements in one, and the replacement elements also made only around 6 firings at 2300 F. The time to reach 2300 F increases with each firing.
My work is technical (small wares dry-pressed from powder). I do not use a cone schedule, and instead typically run the kiln at full rate to the target temperature, with a designated hold time at that temperature. My most pleasing and technically best results come from a feldspar+kaolin composition that requires 2300 F.
I have had to compromise the composition by removing kaolin, adding an organic or sodium silicate binder to replace the binding function of the kaolin, then adding one or another type of frit to get the firing temperature down to 1900-2150 F. This does not give a pure nearly translucent white result, but it is good enough to investigate most other aspects of the process. This without having to deal with sharp fragments of brittle used elements, and abuse of the delicate firebrick. Replacing elements in the close quarters of the Caldera, is not a pleasant process.
It is possible that the Caldera would have a longer element life at higher temperatures, if it were on a lower resistance dedicated circuit.
bny got a reaction from newmatt in Diy Dry Pressed Ceramic Tile?
I was beginning to wonder if I might be the only person experimenting with dry pressing on a personal craft scale.
My interest has been in reconstructing aspects of the process by which china buttons and beads were manufactured from circa 1847 until the mid-1900s. (Prosser process.)
Starting point: 73% G-200 feldspar, 23% EPK. Mix the dry powders, weigh out a portion and moisten with a spray bottle to 6-9% water by weight then grind in a mortar.
I press in a cheap Harbor Freight arbor press, no hydraulics. My typical ware is around 3/4" diameter. I use an ordinary oilite bronze bushing as a sleeve, and dies either improvised from hardware or machined from copper or bronze rod slugs or cast in epoxy by transfer molding from an original object.
The pressed wares can be handled with some care. I sometimes hand drill holes with e.g. #51 drill held in the fingers. Also I smooth off pressing ridges and flaws by rubbing carefully with fingers. Fire at 2350 F at kiln's full rate of rise, hold maybe 20 minutes. They come out quite white.
My little 120V test kiln elements only make 2350 a few times so I often add 3124 frit to get more survivable firing temperatures.
Exploring one reported variant of the old process, I eliminate the EPK entirely, using G-200 and 3124, and add an organic binder. The old process was reported to use milk, but I interpret this as being casein. I use white vinegar to drop casein from milk then press the water out and resuspend in hot alkali solution (sodium carbonate) and dry down to something between slushy paste and quite dry.
70/30 G-200/3124 ad lib the casein, and 8% water will press and cohere, and give a white result around 1900-1950F.
bny got a reaction from mdobay in Rice Paper Oxide Decals
I bought some from japancrafts.com.au . Their web site has a page that gives instructions for applying the transfers. They worked fairly well for me, but I have made only limited use of them and on very small dry pressed wares that were bisque fired to only a quite fragile state. The seller above recommended 1100-1300 C firing.
Dampen the ware with a lightly dampened sponge, apply the transfer, smooth down with a lightly dampened sponge, wait 2-3 minutes then cautiously peel the paper, laying it back down and sponging again if the color is not completely transferring. Too much water will dissolve and run the color.
I read somewhere that these transfers may have a limited shelf life.
There is video online showing similar transfers being printed in China. They were printed by intaglio from metal plates on small hand presses in a very rudimentary workshop.
bny got a reaction from High Bridge Pottery in Gladstone Electrical Wheel Showing E10 On Lcd Display
"Current transformer" very likely refers to a specific circuit component that is not the familiar step-up or step-down transformer within the power supply. A current transformer often looks like a plastic or ferrite rectangle (core) with a hole through the middle and a wire passing through the hole, or wound a few times around one leg of the rectangle. Another pair of wires will be connected to the circuit board.
This is used to measure the AC current passing through the single wire, either as a part of a feedback control loop, or as a safety guard (cut off the power if over-current is detected), or both.
It is also possible that "current transformer" is a misnomer for a DC current sensor that does the same thing with e.g. a Hall effect magnetic field sensor. (Transformers work only with AC, not DC, though they might be used with chopped DC as could be seen in a motor control circuit.) It is cheaper to just put a low-resistance (but high enough wattage) resistor into the circuit, and measure the voltage across that current sense resistor.
Look for something resembling a rectangle with a hole and a wire through it, then look for bad solder joints, broken wires, or loose or corroded push-on connectors on the wires connecting that to the circuit board (the current transformer could be on the circuit board itself), or on the wire that passes through it.
bny reacted to Mudlark in Now That I Know How To Cut Ceramics, How To Drill Them?
Lapidery suppliers stock silicone carbide grit. I use 600 mesh as I have it on hand having bought it for another purpose, a coarser mesh would do just as well.
Brazing rod is used to join metals by heat and can be bought at plumbing suppliers, use one that is not covered in a flux, it looks like brass rod. Any non ferrous metal rod of the desired diameter will do.
Plasticene is a trade name for an oil based modelling clay used by sculptors and model makers not to mention school kids. It's used as it does not wash away with the cooling water as potters clay does.