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Dick White

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Everything posted by Dick White

  1. Re-firing low fire glaze

    If you are using commercial brushing glazes, the brushing agent that makes them brush out smoothly is usually an organic gum (CMC). That also will help the glaze to stick to a previously fired glaze surface. You probably don't need the hairspray trick. That's typically for dipping glazes.
  2. Dry wood ash on glazes

    I never tried it with other glazes. It works well with shino, didn't take it further. Maybe something to try? The Simon Leach method of wetting the ash will take you in the direction of washed ash (there is a whole body of knowledge with washed vs. unwashed ash in ash glazes) and the atomizer will give you a finer distribution of the ash on the side of the ware. And the blue spot is just a finger touch of blue glaze for visual interest.
  3. Dry wood ash on glazes

    No, sadly only 10. My shipment from from Dune was hijacked. And besides, like Custer, it ain't what it used to be, so I had to reformulate it.
  4. Dry wood ash on glazes

    I don't have my photo cube set up, so here is a thumbnail sketch...
  5. Kiln firing variations

    I have heard (but with no scientific proof offered, as I learned of this during a BOGSAT (bunch of guys sitting around talking)) that on a rainy day the water molecules in the ambient humidity are cracked by the intense heat and release some additional energy, whether from the broken molecular bonds or from additional combustion from the now-free hydrogen. FWIW, YMMV. dw
  6. Dry wood ash on glazes

    I frequently sprinkle ash on the side of mugs glazed in shino. I have a small tub of ordinary unwashed fireplace ash (mixed hardwoods, no pine, pine makes a lousy fire and gunks up the chimney flue) that has been dry seived to 80 mesh, which I use to refill an old spice shaker jar that I keep by the glazing table. When glazing the mugs in shino, I immediately hold the wet glazed mug sideways and shake on a patch of "special spice" ash.
  7. Terra Sig question

    A technical question for the terra sig cognoscenti here. Generalized background (nothing new here, just setting up the question to follow): T.S. is made by mixing some clay with an amount of water and adding some deflocculant to cause the clay particles to begin settling out. The larger particles will settle first and the finer particles will remain suspended longer. After a time, the upper part of the suspension with the finer particles is decanted as the T.S., and the sludge at the bottom consisting of the larger, settled particles is tossed out. Issue: As the decanted T.S. rests in its storage container awaiting its next use, it continues to settle out with a much thinner layer of sludgey clay on the bottom of the jar. Question: Would it be appropriate to reflocculate the finished T.S. to retard the further settling of the clay during storage? Would this change the working properties/procedures in any material way? Thanks for all your wisdom and insight? dw
  8. Terra Sig question

    Thanks. Since I have a gallon of it to work with, I will try a drop of vinegar in a half cup of it and see what happens. Watch this space, more to follow... dw
  9. Terra Sig question

    Thanks Magnolia, I am familiar with Vince Pitelka's T.S. page, and have been using that recipe for a number of years now. Here is the practical basis for my questions. My community studio will be having a naked raku workshop/firing in about 2 months, led by the inestimable Ray Bogle. In preparation for that day of fun and games, I made a large batch of OM4 T.S. for the general use of the studio members, resulting in about a gallon of finished sig. I've divided it into several jars, some will be colored with various stains or oxides, others will be left plain white. All are continuing to settle, with the thin layer of sludge sometimes being difficult to stir back up into the T.S. without remaining lumpy. And in the stained ones, the stain drops out first (as expected) but then becomes trapped by the overlying layer of new sludge. Also, if the specific gravity was correct (and yes, I too like 1.15 for this OM4 sig) and some portion of the solids settles out and is not thoroughly scraped up by a less-fastidious student, then the S.G. of the remaining sig will be lower, possibly too watery. Because this will be an intermittent and on-going activity for a few more weeks, I can't do the dry storage technique, so I am wondering if refloccing it with a dash of epsom or vinegar as we do with glazes will keep things floating longer without simultaneously causing the sig itself to become unworkable?
  10. HELP - bartlett v6-cf Won't hold temp

    The 9999 instruction is supposed to cause the controller to go flat out in whatever direction is next. 9999 in a heating ramp is full power on, raise the temperature as fast as the kiln's elements can generate heat. 9999 in a cooling ramp is everything off, crash cool as fast as the kiln can radiate it out. However, I have heard scattered reports that sometimes the controller might react incorrectly to a 9999 instruction. I don't know the explicit conditions or whether it is just some peculiar malfunction of a faulty device. Your report of the 9999->5555 issue suggests a controller fault of some sort, possibly only a minor one. Inasmuch as the 9999 command is "go as fast as you can," you might try a workaround by giving it a more specific ramp rate that in reality exceeds the probable physical capability of the kiln, and let the controller try to keep up. It won't keep up, but it will go as fast as it can. Try setting both of those 9999s at 300 or 400. It would take a very powerful kiln to heat that fast and a thin fiber kiln to cool that fast. I'm guessing that neither of those describe your kiln, so you will get the same effect as if you had programmed the all-purpose general command of go fastest. Another possible solution is try entering your program into a different User number. Maybe there is some corruption of a bit or two where that instruction is supposed to be loaded into memory?
  11. As Neil recommends, shut it off, it's not going anywhere new tonight. Also reconsider your notion that everything is 100%. If I were going to place a bet on one single item, I would bet that your elements are long overdue for replacement. That they have electrical continuity does not mean they are producing the designed amount of heat. Get a multimeter if you don't already have one and measure the resistance of each section at each switch setting, and compare to the specifications in the Skutt document at https://skutt.com/pdf/service_manual/11-5_ks_resistance.pdf As noted in the technical reference, if your measured resistance is more than 1.5 ohms over the spec, that will explain why the kiln never got to temperature.
  12. Newbie without bentonite

    The recipe contains 8% kaolin and 17% gerstley, so it should stay suspended reasonably well without the bentonite. There are various types of bentonite. Some used in cosmetics and soap might not be appropriate for ceramic glaze . I would be careful without knowing exactly what type of bentonite was used in the facial mask. Whiting is sometimes used in the paint industry as a white pigment, but in a ceramic glaze it melts into calcium oxide, a flux, and would change the glaze. If you are seeking to opacify it, use one of the materials suggested by Min.
  13. New Element Diagnostic Results

    My initial reaction is the same as Frankiegirl. If a kiln designed for 240V power is plugged into a 208V circuit, it won't get above 2000F, it that. Look at the electrical rating label on the side of the control box and see what it says is the designed voltage.
  14. Malcolm Davis CT Shino (Redart Question)

    I have found that shinos are toasty rusty red/brown when applied thin, and white when applied thicker. For the carbon trap, it has to start with the thicker application that would otherwise be white but for the early reduction.
  15. Black Raven mason stain turning brown

    Zinc is not your friend. First off, Raven Black is not a Mason stain, but rather is a Drakenfeld stain by Cerdec. However, the problem is the same. The oxides used to create the black are chrome and iron. Chrome and zinc = brown, not black. I can't find a document from Drakenfeld/Cerdec about the necessity to use a zinc-free glaze, but you might check the reference chart at http://www.masoncolor.com/reference-guide for comparable information.
  16. When firing a kiln, the concepts of temperature and rate of increase are a conundrum in that it is possible to both place too much importance and too little importance on the precision of either number. Because electronic controllers are just dumb specialized computers, one must tell it what to do and it will attempt to do exactly that, hence all the mumbojumbo about rates and temperatures. However, the reality of the ceramic process is that there is considerable leeway around it, most of the time. There are a few times during the heating process that the rate of increase should be slowed down to prevent physical damage to the developing ceramic, specifically at around 900F and again at around 1150F. The firing schedule suggested above by dhPotter, starting with switches on low heat, then turning the switches up over a period of hours will accomplish this without needing to worry about the exact rates and temperatures. Low and medium will not provide enough heat to exceed the limits. The final stage of heating is a different kettle of fish. This is where the witness cones are essential. The cones measure heatwork, not temperature. Heatwork is the penetration of the heat into the ceramic body, and that occurs over time. It you increase the temperature very fast during the last 2 hours of the firing, it will still take time for the heat to penetrate to the center of the ceramic, which means the actual temperature of the air in the kiln will be higher when the designated cone softens and bends. If you increase the temperature during the last 2 hours very slowly, the heat will be penetrating into the center of the ceramic at almost the same rate, and the cone will soften and bend at a lower actual temperature. When you have a manual kiln, you turn it to high, it does what it can to heat the contents of the kiln (the manufacturers design their kilns to have enough heating power to do what is needed), and the cone bends when it is done. That's when you turn it off. If the load is light and it heats faster than usual, it will heat to a higher temperature and the cone will bend when it is done. If the load is heavy and it heats slower than usual, the cone will bend at a lower temperature and then it is done.
  17. My opinion aligns with Neil's (bad pun, ducking and running). To put things in more physical terms, IMO, on-center is a perfectly round outer surface around the center line of the wheel's axis of rotation. Fully centered is when the mass of clay is both on-center (round, as previously defined) and the vertical axis of the center of gravity of the clay mass aligns with the on-center axis of rotation. Clay as a material can have, and usually has in its natural condition, variable densities within the mass. Areas within the ball of clay where the platelets are more aligned are more dense, and consequently have more actual clay per cubic whatever than areas where the platelets are not well aligned. Thus, the center of gravity/mass is not in the center of the volume. If one were to open an on-center but not fully centered ball of clay, the side that has the aligned dense area will have more physical clay and thus will create a thicker or taller (usually both) wall compared to the other side that started with less clay. Once the ball of clay has been opened, clay does not move around much. Squeezing it to raise the wall causes the wall to get thinner at that location by displacing some of that spot of clay slightly upward (thus generating height in that location) or tangentially (thus generating circumference (which yields diameter) at that location). Otherwise, the clay does not move. In exaggerated stark terms, despite what it might look like, raising a cylinder wall does not entail moving clay from the base to the top and building up from there. Likewise, once the ball has been opened and raising the walls has commenced, clay does not move around the circle. If there is are any more dense and/or less dense sections, they will remain where they are and the resultant wall will be uneven at best. Think of it like tires on a car. Unbalanced wheels, despite being round, will be a bumpy ride. The clay can, and does, move around inside the ball when it is still a solid mass. Coning up and down achieves this. Proper coning up produces a spiral jet up through the center of the cone as it rises. At the same time, the friction of your hands against the side of the rotating cone causes the platelets to collapse into alignment, to a depth of about a half inch. The aforementioned spiral jet brings additional disorganized clay up from the base for alignment as the cone rises. Taking the cone back down properly, redistributes the aligned clay evenly around the outer layer of the mass. Because it is not possible to get all the the clay aligned in a single pass of the coning, you must run it up and down several times. Each time the spiral jet brings more up from the base, until it is all aligned. You can tell when you have more alignment to do by watching the very top of the cone as you complete it. If the tip is lumpy, there is probably more in the lower center of the mass that hasn't yet been worked. Smooth the lumpy tip with your thumbs, take the cone back down properly, and squeeze some more disorganized clay up from the bottom center of the mass. When the cone tip finally comes up smooth and clean, you're done centering. Take the cone back down and carry on. It is true that an expert potter with very strong and steady hands can pinch the rotating clay into some semblance of centered without all the coning, but the rest of us need to cone. JMO, YMMV. dw
  18. Genesis Controller

    Neil, see page 21 of the current manual, "Export Log File" within the Configuration/Communications menu. Then pull the log file into a spreadsheet.
  19. Brent wheel pedal repair

    Thank you Mark and Neil. I will order the cheap one and reuse the old wire. I have another one with a badly damaged wire and I will probably make a new wire with hardware store parts - if only just because I can.
  20. This question is for those who are deeply steeped in the technical details of the Brent wheel control circuitry. We have a community studio with 18 Brents of various types and vintage, and I have the joy of keeping them running, albeit with not much of a budget. Over the past 10 years I have repaired/replaced one of just about every type of part in them ( though not in all of them - they generally have been very durable) either through some clever frankenstein scavenging or the equally clever political maneuvers through unknown parts of the county bureaucracy by my predecessor who left me a sizable stock of a few things that I have been working my way through over the decade. Several years ago I used my last pedal sliding potentiometer thingy and now have another inoperative wheel because its pedal failed. Stumbling around on the Brent website looking to purchase the part, I see they have one with short pigtails and modular connectors for $73US and another with the full cord for $110. Ours all have the full cord, but before I choke on the extra $40 for 2 feet of wire, does anybody know if the electronics and functionality of these parts are the same? I'm perfectly happy to put connectors on the ends of the old wires if it would save $40. TIA dw
  21. I have found with hump molds that often the very edge of the slab needs to be gently picked loose from the edge of the mold/form so that the slab is not hooked over the edge and can slide upward slightly as the overall slab shrinks while drying. Usually the rest of the slab will release easily when it has dried slightly, but don't take it off until it is dry and strong enough to hold its shape on its own.
  22. Pyrometer Usage?

    I agree with the recommendation for a protection tube. First, as noted, it will protect the thermocouple both from striking it with a shelf and from the corrosive fumes so it will last longer. But it is protection in the other direction too. The exposed tip will corrode and a rusty powder will begin to flake off, landing on and contaminating any glazeware underneath it. Before I installed protection tubes, I had to leave that segment of each shelf empty. However, there is another thing to keep in mind with protection tubes. They do have a slight insulating value, so the thermocouple will read cooler than the actual kiln temperature. This will also introduce lag, meaning that during a heating or cooling ramp the temperature change sensed by the thermocouple is running behind the actual performance. Electronic kiln controls typically have offsets and adjustments that can be programmed, but with a handheld pyrometer, you are the computer.
  23. Prediction required

    Looking at it in Glazemaster, it should be ok, though different as Mark correctly predicts... The alkali level is higher (.26 now vs. .22), but not out of range. However, now the alkali content is dominated by sodium from the frit vs. lithium from the spod, and this changes the expansion quite a bit so there might be a glaze fit problem. The Si:Al ratio is lower (6.5 now vs 7.2) because of the added clay, but not completely out of range. The big change is in the boron - now .28 vs. .07. That will add some melting and gloss. Let us know how it looks when it comes out of the kiln.
  24. L&L Kiln - E22 & 26 Error Codes

    Get the refurb Genesis. You're paying half what I paid for mine directly from Barlett. I wonder if they will sell me a refurb, I have 2 other kilns that could use an upgrade at half price...
  25. Relay Life Update

    Thank you Neil for stepping up.

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