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Dick White

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Everything posted by Dick White

  1. Be aware that manual Skutts with the 4 way switches operate as follows - Low turns on only the bottom element of the respective section (which would be the bottom 2 times around as each element goes around twice). Medium turns on both elements of the section, but they are wired in series. High turns on both elements, but now wired in parallel so they give off more heat than in series. Thus, if you are giving it a visual test of glowing, then you need to turn it on high to have everything come on bright enough to see. When things are all on, the topmost and bottommost coils in the kiln will be
  2. Here is a link to a pdf from L&L about firing their manual kilns. http://hotkilns.com/sites/default/files/pdf/fire-manual.pdf
  3. Is she using the same kiln? Propane has more BTUs per volume of gas than natural gas, so the orifice for a natural gas burner is larger for the same amount of heat. If it is the same kiln but the orifices in the burners were not changed for propane usage, they are burning much hotter than before.
  4. Cindy, welcome to the zoo here at CeramicArtsDaily. The Dawson Kiln Sitter company went out of business some years ago, but Skutt bought the rights to it all and still makes the parts. You can order them directly from Skutt or from other online sellers of kiln repair parts. There are several configurations of the kiln sitter, so you will need to take yours apart to measure the length of the tube and order one the right size and method of attaching to the face plate of the sitter. It's not hard to do, just that you have to get the right piece.
  5. Your kiln is a manual kiln - there are no relays, just switches. The 4-way rotary switch works as follows: On low, only one element of the pair is turned on. On medium, both elements are turned on but they are connected in series. On high, both elements are turned on but they are now connected in parallel, which generates more heat than when connected in series. Check again with the switches at all the various settings.
  6. It may be counter-intuitive, but s-cracks that suddenly appear after the glaze firing were there all along, caused by faulty throwing and drying of the greenware. The clay shrinks twice during the usual sequence of work. The first shrinkage occurs between the time of finishing wet work to bone dry. It is merely the water evaporating and the space previously taken by the water closing up. There is no further shrinkage in the bisque firing. If you put damp work in the bisque firing, there will be some shrinkage as it finishes drying in the kiln, but no more once the actual firing commences. A se
  7. There is only one brand of kiln sitter - Dawson, which is now owned by Skutt - and the functional parts inside the kiln are all the same. There is only one calibration gauge. You can buy one from any place that sells parts for Dawson kiln sitters, not just from Skutt or the manufacturer of your kiln. It's a little round disk that fits over the ends of the cone supports and holds the actuator rod in the exact spot when the drop weight should fall.
  8. Fire the kiln empty to cone 04. This will build a protective coating of oxide on the elements, which will help them last longer.
  9. This has been an interesting discussion. Let me add some things from my experience using Advancers in our gas kilns for the past 8-10 years. Most glaze blobs will pop off with a stiff putty knife, but there will be lots of other little stuff that will need to be removed with an abrasive because there isn't enough to get the edge of the putty knife on. We use an old worn down green grinding wheel held sideways on the shelf and rubbed in circles over the entire surface of the shelf. Five or 10 seconds per shelf is usually sufficient, and since it is hand work, there isn't the cloud of dust float
  10. Solid state relay. A relay is an electrically controlled switch. A low voltage current from the digital controller causes a heavy duty switch to close and turn on the elements. When the controller determines the elements have been on long enough, the low voltage current stops and a spring clicks the switch open. That is the loud clicking during the firing. A solid state relay replaces the the spring and mechanical contacts with electronic semiconductors. Silent, reliable, long-lived, and more expensive.
  11. This is an interesting topic from which I hope to learn something new. I'm familiar with the Advancer shelves, we have them for our 2 gas kilns at school. (But there where we have foundation money to pay for them, money is no consideration...) However, the notion of savings from SSRs is new to me, so please help feed my hungry brain. I can see how an SSR could cycle faster than the standard electromechanical ones, but how is this controlled? Is there a hidden option in my Bartlett controller for this?
  12. I built a small waterfall booth out of two plastic laundry sinks stacked and screwed together like a clam shell with the front side of the upper one cut away. The waterfall is made from standard small pvc plumbing pipe with small holes drilled in it every several inches, arranged around three sides of the top. The water flows down the sides and out the drain in the bottom of the lower sink and into a tub sitting on the floor underneath. This tub is half full of water and has a standard sump pump in it to recirculate the water back up to the piping at the top. Because there is no need to pull t
  13. The wires on the kilns aren't long enough to reach the ceiling. They are hardly long enough to reach a wall behind the kiln after allowing for the required 18-24" of space behind the kiln plus a bit of slack so the wire is not directly touching the kiln body. If you are going to put the kilns near the PVC wall, you will need to install something fireproof/heatproof on the wall so the radiant heat from the kiln doesn't damage the wall. By the time you install a stud structure for that, you might as well put the electrics on the same framework. While you are at it, install cut-off switches befo
  14. Chrome-tin reds are finicky, very narrow range for success. If the ratio of chrome to tin is mismeasured, or if the chrome-tin combination is used in a different base, it might not work. Also, they need a thicker application, and will be blah gray if too thin.
  15. Nancy, I have an ancient Econo kiln, to which I have added an external controller. I also have a separate thermocouple/pyrometer harnessed to a computer with a logging program with which I can create a minute-by-minute profile of the actual firing performance. I have found that no matter the ramp schedule I program into the controller, the old kiln can only manage around 100F per hour at the very end coming into cone 6. So, with your new kiln which has the power to actually produce the higher ramp rates of even the "slow" cone fire final ramp, you are firing hotter and faster than before. Kno
  16. hmmm, trying to get my head around this. My previous understanding (which, like so many other things I thought I understood, may be a colossal misunderstanding) is that the (theoretical) kaolin molecule is Al2Si2O5(OH)4 . As it is fired towards and past 1000F +/-, the molecule reorganizes into the conventional ceramic oxide molecules of one Al2O3 and two SiO2, plus two H2O molecules that immediately evaporate. Once the extraneous water molecules are gone from the calcined kaolin, you can't put them back in conventional time and ambient conditions. (Of course, in geologic time and conditions,
  17. My understanding of the issue is that the controller electronic board is fine in cold temperatures. It is the thermocouple that causes issues at low temperatures. The thermocouple operates on the principle of the galvanic electric current (which is minuscule, measured in milivolts) generated at the intersection of two dissimilar metals. The hotter the joint is between the two metals, the more current it generates, and the controller measures this increasing electrical voltage to "know" how hot the kiln is getting. The ubiquitous K-type thermocouple is made of chromel-alumel, for which the decr
  18. Unlike oxidation, in redux there is no such thing as a white stoneware under a transparent clear glaze. In reduction, iron turns black, green, or blue depending on what other chemistries might be present. A white stoneware will have some iron contamination of the clay. This remains unnoticeable during an oxidation firing, but a reduction firing will bring it out. The iron in the clay will cause the white stoneware to turn grey during body reduction, and the glaze as it matures will flux some of the body surface and draw the impurities up into the glaze, causing it to discolor. The only way to
  19. If you are rolling the coils on a canvas work surface, dampen the canvas rolling area first. Then the coils will not dry out as you are rolling them.
  20. I too use the Future acrylic floor wax, now branded as Pledge Floor Care Finish. As nobody has linoleum floors that need to be waxed anymore, most stores selling household care products don't carry it, so I now order it online from the big river in South America. I apply 2 light coats with a foam sponge, and you can handle it very soon after applying the wax. Straight from the bottle, it will be pretty glossy, but I've found I can reduce the gloss somewhat by cutting the wax half and half with water.
  21. We bisque fire to the lower cone so that the wares will be strong enough to handle while glazing and still porous enough that the water in the glaze slurry will be drawn in and the glaze will stick to the surface. When a piece is mistakenly fired to glaze temperature, the surface is now nearly vitrified, no longer porous, and it will be much harder for the glaze slurry to stick to the piece. The second glaze firing will still be the same as usual so the same glazes can be used - if you can find a way to make them stick. If you are using premixed brush-on commercial glazes, they contain an orga
  22. And if it comes with shelves and posts, it is an excellent deal. (Assuming it's in good shape. If not, then it's $200 wasted...)
  23. Andrea, Happy Christmas to you and your family also. Typically when an appliance is manufactured for multiple international markets, the literature is generic and avoids country-specific data. Two ways you can ascertain the exact specification of that wheel: 1) look for an electrical rating tag somewhere on the control box that indicates the voltage and amperage drawn by the device; and 2) is the plug on the end of the power wire consistent with your local wall receptacle? If that unit was intended for the US 120V market, the plug would have American-style prongs, or if intended for sale in a
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