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Dick White

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Everything posted by Dick White

  1. That's a very good price for the Genesis controller, I wonder why they are selling them for half the price Bartlett sells them - unless as @neilestrick suggested, that is the upgrade price if you want a Genesis instead of the standard version on a new kiln you are buying from them. If you are getting one raw, as @Bill Kielb and Neil said, it is a direct swap for the Bartlett V6CF or L&L Dynatrol (which is their private label on the V6CF). The wires will be the same except the thermocouple terminal has been moved from the left side (facing the back of the board) to the bottom of the board.
  2. Yes, definitely a refractory coating, about 1/16" thick. It is cracking and lifting off the surface in a few places. I've avoided manipulating it out of fear it will all peel off. Thanks Bill for finding that bit of a Skutt maintenance page. It definitely looks like a flipper. Interesting idea Mark for the ITC. I don't think I have enough left over from when I did my whole kiln over 10 years ago, so perhaps I'll order some more to do the tops-soon-to be-bottoms. Thanks for the advice.
  3. Pictures in the morning. These are OEM Skutt lids, no repairs that I know of. I installed them probably 10 years ago and am the only one who performs maintenance in that studio (new elements annually, kiln sitter parts as needed, etc.) and I never did anything to the lids. Yes, I understand lids are not generally coated, or at least none of the dozen or more L&Ls and Paragons I've worked on over the years had any coating on the brick lid, but these Skutts do.
  4. I have two older Skutt 1227s at the community studio on which the coating on the underside of the lid is cracking, separating from the brick, and dropping crumbs onto the ware on the top shelf. Does anyone know of a repair method for this coating? TIA, dw
  5. Your math is correct. 2% of 100g of base material is 2g of colorant. 2% of 1000g of base is 20g of colorant. Etc. I don't have an absolute answer whether 2% of cobalt will give you the eggshell blue you want. Too many variables - cobalt carb or oxide? how pale is pale in your opinion? Test a small batch to see if it comes out the way you like it.
  6. It is my opinion and practice that shelves should always (if possible) be arranged so that they are between rounds of the elements. You want the elements to be heating the wares on the shelf, not the edge of the shelf. This is particularly important at red heat and above. At those temperatures, the heat is transmitted by radiation, not by convection. The elements are the source of the heat in the kiln, and should be exposed to the ware. And yes, you need to build around the thermocouple(s) too.
  7. We have been using Advancers and the less expensive Bailey version in our gas kilns at the college for many years. They do not need to be coated with kiln wash as any glaze runs just pop off with a stiff putty knife or the flat side of a worn green grindstone. As they are not washed, there is no up or down side; they go into the kiln however they are picked up from the rack. Yes, the ends of the posts need a light coat of wash as they will slightly fuse to the shelf. They have remained perfectly flat all these years, unlike regular shelves. There will still be some need to ensure the flat slab
  8. The problem in extreme cold is not the thermocouple or the control board hardware. It is the control board software. The K-type thermocouple will read temperatures well below freezing, as noted in the table posted by Bill above. Also note in the table that the millivoltages are all negative. Several pages further down in the table, where the temperature crosses 0C/32F, the voltage turns positive. The Bartlett controllers are built to read only positive voltage from the thermocouple. It doesn't "understand" negative voltage so rather than operate in a confused manner, it turns itself off.
  9. Can you get your hands on a clamp meter? It has "fingers" that encircle an electric wire to determine how much amperage is flowing through the wire. Per the design specs, the kiln, with good elements, should be drawing 45 amps when full on. A clamp meter on the main power wire should have a reading in this neighborhood. Check it while the kiln is maxing out and stalling to see if it is still drawing full power.
  10. I'm getting confused now. I looked up the SNF-24 manual, and Bill beat me to posting it. The top switch is an infinite switch with variable settings between low and high, for 4 rounds of elements distributed evenly throughout the kiln. The middle and bottom switches are timers that set a delay before turning on additional sets of 4 elements, also evenly distributed throughout the kiln. But these switches are full on as soon as its time delay has expired. The design intent is that the infinite switch sets an amount of heat to first turn the kiln on slowly, and then by the end provide just enoug
  11. Some have placed their damp ware in the kitchen oven, set to as low as possible (around 175F) until completely dry. Then transfer to the kiln and fire.
  12. Google is your friend (sometimes). https://books.google.com/books?id=4_Q0DZNjdPkC&pg=PA66&lpg=PA66&dq=bumper+jack+extruder&source=bl&ots=ruA5LSKyP8&sig=ACfU3U1CvfcTWI1Ca244CLP5VqP6l6sR5Q&hl=en&ppis=_e&sa=X&ved=2ahUKEwiLvsnN_bLmAhWkslkKHepSBGYQ6AEwDXoECA4QAQ#v=onepage&q=bumper jack extruder&f=false
  13. Sometimes the mini cones have an unseen fault that causes them to break rather than bend smoothly. When that happens, it might turn the kiln off right then, or it might jam in the sitter mechanism and the kiln keeps firing. And firing. And firing... Always set the timer (if there is one) to slightly longer than anticipated (so it will turn the kiln off before too long if the cone fails), and be there when the firing is expected to end and turn it off when the witness cones in the kiln indicate it is done.
  14. When you say "resting ... on the fire brick," are you using soft IFB brick or hard brick as the support? I used to put a cool shard of broken kiln shelf (of which I have a whole bucket, just for this purpose) on the hot shelf before loading each piece of ware on it to alleviate the initial thermal shock. Then I "discovered" setting an IFB brick on the shelf and loading the ware on it - don't have to swap out the brick for each new piece despite it looking like it is red hot. When I have a leaning piece such as yours, I set another IFB brick on edge to lean against. Now most of my breakage is
  15. I use an acrylic floor wax, previously sold under the brand name Future, now sold under the name Pledge Revive It Floor Finish. Others I seen use an acrylic spray varnish.
  16. Well, now that we've tumbled this deep down this particular rabbit hole, a sidebar about the voltage chart... if you download it an read to the page that covers temperatures around 0C/32F, you will notice that as the temps go down, the voltage changes to negative at that point. This is why a Bartlett kiln controller is rated to operate only down to 32F/0C. It can't deal with the polarity of the voltage from the thermocouple flipping. But the controller itself is fine below freezing, you just have to do something to warm the thermocouple enough to register positive voltages and then the contro
  17. A thermocouple / pyrometer is a simple electrical measurement device. The junction of the dissimilar metals in the thermocouple generates a very small galvanic current which increases as the temperature of the junction increases. The pyrometer measures the voltage from the thermocouple and using a conversion factor built into the device, displays it on the screen as conventional temperature. A multimeter can also measure the voltage, but then you must do the math to convert from micro millivolts output by the thermocouple to degrees of temperature. Edit: Upon looking at the harborf
  18. When I first became interested in crystalline glazes (in a school setting where we had digitally controlled kilns) I had only a manual kiln in my home studio. Fortunately my kiln had "infinite switches" that can be dialed up and down as needed rather than single or H/M/L click switches. The infinite switches are critical to be able to tweak the heat input to exactly match heat losses so as to maintain your predetermined temperatures during the crystal growing period. You will also need an external pyrometer and thermocouple (poke the thermocouple through a peephole and pack the space with some
  19. As I noted in this thread back in Dec, Terry is The Man Behind The Fallonator. Plumbing of the highest order meets pottery of the highest order! dw
  20. What Mark C. said. The caps are black rubber, and form an integral part of sealing the chamber when vacuum de-airing the clay before pugging it out. It has been my experience with both our Peter Puggers that if the inside of the rubber cap is not kept clean, it will not properly seal and a vacuum cannot be achieved. Thus, regarding an earlier suggestion of putting a piece of plastic over the end of the barrel before putting the rubber cap on over it, that may or may not produce an adequate seal for the vacuum process. Try it, YMMV. And yes, both our PPs leave a blue-green-grey stain in the ce
  21. Magnesium oxide is a flux that helps a glaze melt and imparts certain characteristics to the glaze surface. It is not generally regarded as toxic, and is found in many over the counter pharmaceuticals. It is not a colorant. Are you asking about manganese dioxide?
  22. Uneven stress between inner and outer glazes will cause this. It doesn't matter if the uneven stress is inside to outside, or outside to inside. Keep your single inner layer of Licorice but go easy on the multiple thick layers on the outside. If you must layer the glazes on the outside of your mugs, do it with thinner coats so that the total glaze thickness approximates the single layer inside.
  23. The issue of "distance" from the panel is one of voltage drop. In order to deliver the necessary amperage and voltage to the target device, the wire needs to be the proper thickness. More amps requires thicker wire. That's standard stuff, kiln manufacturers list the requirements in their specifications. But excessive length of the wire may cause a decrease in the voltage. 50 feet is about as long as you can go without incurring some voltage drop. However, this can be remedied simply by increasing the thickness of the wire. When your electrician installs the wiring, ask him or her to calculate
  24. The video in the URL starts with a still photo of a lidded box with a black and white top and red chattered sides. I didn't see the vase. The top of the box lid was a slab, textured with a roller, shaped, and then applied to the top of the open thrown cylinder. The glaze on the top of the lid looks to me like a temoku type of dark transparent glaze that breaks clear over the edges of texture,
  25. I have found with my homemade sig that the surface of the bisqued ware is so tight that studio-mixed dipping glazes aren't absorbed properly and the glaze is too thin. Perhaps commercial brushing glazes will adhere better?
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