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Dick White

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  1. Just a sorta-humorous note along these lines... We had been talking about this, and though the college studio where I am a studio monkey was closed because of the pandemic, I suggested to the professor that she should order some to get us through the however long the shortage might be. We reopened yesterday for modified in-person studio work, and there on a cart were 4 bags of it, enough to last us the rest of millenium.
  2. Gare Kilns were taken over by Evenheat. User manuals for the old Gare kilns aren't among those published on the Evenheat website, but if you call them, they are helpful and can get the old manuals out of their archives for you. As for the capabilities of the kiln, some of that should be listed on the electrical rating plate that is attached to the side of the kiln or the control case. If you post a picture of that, we can see what it looks like. dw
  3. Having dabbled in crystalline glazes more than a few times, my understanding of the process is there is way way way too much zinc (25%+/-) in the recipe for a "normal" glaze, but it is all incorporated into the melt at peak temperature in what might be similar to a supersaturated solution. There is very little calcium or alumina so that the molten glaze is nice and loose (runs like the dickens) for the crystals to grow without any impediments. While the silica molar level is low in absolute terms, with almost no alumina, the Si:Al ratio is over the moon. As it slowly cools, the zinc molecules precipitate out and readily find the excess silica molecules to form and grow the big zinc orthosilicate crystals during the multi-hour hold at temperature. I will try to put in a picture from EU-Cal of one of my recipes. The excess silica is 7.55 and excess zinc is 3.44. That stuff has to go somewhere, so it forms crystals. The crystals also absorb colorants that are in the recipe, but in a standard order of electron valence, leaving some of them in the background. I have not tried a reduction firing, but those crystalliers who have report it's a hot mess if reduced on the way up, but if there are reduceable colorants in play, they will do all sorts of pretty things on the way down after the crystals have formed. (@BobMagnusonAwesome tool, btw. I will be sending you a request message later.) EuCal_ver1_9dw.pdf
  4. Well, actually, there is a problem that is specific to the Shimpo Whisper, Giffin has acknowledged it and is trying to develop a solution. I don't know the progress on that. The physics principle involved is that when you accelerate the wheelhead, the differential momentum of the accelerating wheelhead (which the lower part of the Grip is attached to by the friction of the legs) vs. upper plate of the Grip which is still stationary or rotating at a slower speed will cause the pads to move slightly inward on their spiral tracks to maintain the grip on your piece. With the direct drive electronically controlled motor of the Shimpo Whisper, when you take your foot off the pedal to stop, it stops so fast that the differential momentum between the top and bottom plates of the Grip reverses, the top plate keeps spinning slightly after the wheelhead stops, and the pads are moved slightly outward on their spiral tracks. Every other brand of wheel comes to a stop slowly enough that the friction between the top and bottom plates of the Grip keeps everything in place. @AlexX If your wheel turns counterclockwise for throwing, etc. , then the top plate of the Grip should rotate clockwise when the wheel is stopped to tighten the pads. Hold a finger against the side of the wheelhead to be certain it doesn't move, and turn the top plate of the Grip each way to see which direction causes the pads to move in and which direction causes them to move out. If they move inward with a clockwise turn, then you have the counterclockwise model. If they move inward with a counterclockwise turn, then you have the clockwise model. Yeah, that's a head spinner in more ways than one... The upper and lower plates of the Grip need to be rotating in opposite directions with respect to each other to tighten.
  5. While waiting for your pictures, a kiln must be on a circuit that is 125% of the amperage of the kiln. Yours is 24 amps, so a 30 amp circuit is needed. The 8 ga. wire is more than enough. Leave it alone. Your kiln had a 50 amp plug. This is probably just a convenient coincidence, as that is what larger kilns use, so perhaps they just built them all with the same power cord, less inventory to keep on hand in the factory. It doesn't need to be 50, but that's what was there. You've already cut it off, so you are stuck with that. It would have been easier to change the outlet on the wall for one that fits the plug, but you are where you are so put the plug on the power cord. Your picture of the circuit breaker for the kiln is cut off, can't see the numbers on it. Note that on 240V double pole breakers, the number on the handle is for each side of the circuit, but they do not add together, i.e, if the numbers are both 30, it is 30, not 30+30=60. However, If it is truly a 60A breaker (both numbers are 60), that is dangerous. The kiln only needs 30, the 8 ga. wire is only good for 40, but the breaker won't blow until a 60A error occurs, at which time the kiln will already be fried and the wiring on fire (that's a bit of an exaggeration, but don't have a larger breaker than the wire can handle or significantly larger than the kiln draws even if the wire is ok at the higher amperage). However, it is ok to have a smaller breaker than the wire size, just not the other way. So, change that breaker to a 30A and your kiln will be good to go.
  6. Ha. For some, this glaze chem stuff IS wilderness camping. All. The. Time.
  7. This is an interesting and useful discussion. I too have noticed the top and bottom sections "working" harder than the middle, but didn't put it together the way you just did. I wonder if this is where Skutt gets it by putting hotter elements at top and bottom? If one paid extra for a Skutt with 3-zone control and the touchscreen, would the data dump show the top and bottom sections at lower percentages, closer to the middle section to maintain even temperature?
  8. This may be a bit geeky for the average artist, but with the Genesis controller, you can extract a data file for each of the last 10 firings that lists the setpoints, actual temperatures, and percent of power-on time every 30 seconds. Import that into a spreadsheet like Excel and calculate rates of temperature rise at various stages of the firing and for each section of the kiln. If you are facile with the spreadsheet, you can construct graphics of programmed vs. actual. Like I said, it's a geek's toy, but it can be useful to see where the variances are from expected in the programming and imbalances between the sections. This is particularly useful when elements begin to wear and the ramp rates at higher temperatures begin to significantly lag the program. You can see how the run up to bisque seems to be normal while glaze firings go on forever until the dreaded E1. I've also used this by setting a high ramp rate for a long cooling segment down from peak (set it to over 400F/hr) just to keep the controller from turning the elements on at all while logging the natural cooling rate of the kiln. I doubt you'll find a brand new kiln to be generally lagging the expected program, but it can help diagnose section imbalances that can be tweaked with a thermocouple offset.
  9. This has been discussed before. The main supplier of talc in the US is (was) AM-TAL, in Texas. For better or worse, Daltile, the big wall and floor tile maker uses so much talc in their production that it made business sense for them to just buy the whole mine a few years ago. Recently, they made another business decision to end outside distribution of the talc as of this month, only producing for internal use now. Yup, there is going to be some disruption. There are some other smaller talc mines, but it will be awhile for the market and distribution to settle.
  10. @neilestrickSince we are on the topic of offsets and Morgan mentioned cone offset, could you expand on your experience with individual cone offsets vs universal TC offset? I get how the offset allows one to calibrate the controller's expectation of precision to the reality of the thermocouple's relative imprecision. But why would one adjust the offset in just one cone-fire value? If the TC is off by the 10 degrees in your example for Morgan, wouldn't it be off by 10 degrees, more or less, everywhere in the usual firing range? That would mean setting a cone offset for every cone in the controller. If I set 10 degrees in the offset for cone 6 because that's what fire my glazes to, cone 5 and 7, etc. are still whack should I decide to do a load of some different glaze at something other than cone 6? Or, is the TC offset variable across the firing range and some cone settings need more or less offset? That could be a challenge to test and dial in all of them.
  11. What I was trying to do was use my logging pyrometer connected to the same thermocouple as the controller to keep track of what the controller was seeing/doing. I attached a separate wire directly at the thermocouple block. When I noticed the readings bouncing around, I gave the thermocouple back to the controller rather than have the kiln load bolloxed.
  12. As one wag said, anything is possible, but some things are not likely. My one attempt at that was not satisfactory. I connected a separate pyrometer to the same thermocouple as was being used by the kiln's Bartlett controller. The temperature readings went jittery and I couldn't tell what was going on. Haven't tried it since.
  13. Well, actually, according to Orton, a self supporting cone is correctly fired when the tip is even with the top of the pyramid supporting base, not touching the cone pack/shelf as with regular cones. But the reality is there probably is only a few degrees/minutes difference between even with the top of the base and the shelf, so no harm. And as Bill pointed out, consistency with your glazes is what matters.
  14. I don't have a paper book copy of the manual here, but the download pdf version has a section titled "First Firing Instructions for L&L Kilns With A Dynatrol 700" immediately before the Bartlett Genesis chapter. That's where the slow bisque business is listed. Which, of course, yours isn't "with a Dynatrol," yours is with a Genesis. So that's poor editorial decision by L&L. And it's probably not the end of the world, but that's how we got where we are. Namely, all in it together.
  15. The Genesis section of the L&L manual is a reprint of the Bartlett document. It gives a first firing example of a fast glaze fire to cone 04 or whatever cone the manufacturer included for that initial firing, but notes one should follow the kiln manufacturer's instruction if different. L&L provides self supporting cone 5 cones for the initial firing, but also calls for slow bisque, not fast glaze. I doubt the kiln is irretrievably ruined because of fast glaze vs. slow bisque, but my understanding is that the L&L special coating on the bricks needs more that the 04 firing that Skutt (and others) specify. (And yes, you can get out the popcorn when the Skutt crowd starts arguing with the L&L new owners about this in the Facebook groups...) The only thing I would add, mostly for the general edification of anybody reading along here, is don't rely on exactly what happened in the first test firing of an empty kiln. A full kiln will respond differently. Use cones even with a controller to ensure that the controller and thermocouple are working together properly to produce a consistent outcome. After several firings to develop an average of different loadings, tweak the offset as needed to perfect the controller. Keep using cones forever as things will drift with age. Y'all get back to work now.
  16. That's an old one. L&L Econo kilns haven't had H/M/L switches since forever ago. The operation of that style switch is two elements per section running in series on low, only one of the elements running on medium, and both elements running in parallel on high. My experience with such switches is that when they get really old, the internal contacts begin to degrade and the switch overheats, and sometimes a particular switch position works and sometimes not. If you open the box and look at the back of the switch, you can see the overheated connectors and they will wiggle because the internal structure has melted. For better or worse, the company that made those switches (which are used by many kiln makers) stopped making that particular switch after a corporate change of ownership. You might be able to get one from L&L if they have some left in a drawer in the back closet, but Skutt (which used the same switch) is selling a replacement made by a different manufacturer that has a different pin-out on the back of the switch, for which Skutt has a nice instruction sheet how to rewire from old to new. I've put a few in the Skutts I have at the community center, but I am finding they are showing burn damage much faster than the old ones. I've also heard through the grapevine that Paragon (another kiln maker that used the same switch) is backordered on replacements. I don't know if they are having supply issues, or maybe they are noticing a quality issue? But back to MOConnell's kiln, my money is on crapped out switches. But also do the continuity and resistance tests that Bill suggested as there might be issues with the elements.
  17. Mark, my bad halfway... looking at the label on mine now, it is 115V DC, not 90, 1/2HP, 5 amps.
  18. Not so much about the initial question (replacing the pedal pot) but regarding the later comments about motors and voltage - dunno about what Brent was doing back when the earth was still flat, but I believe Brent motors now are 90v DC. The controller rectifies whatever design input of local AC voltage and the pedal pot instructs the controller to increase/decrease the DC voltage to the motor to make it go faster or slower.
  19. To add to that, buy one from your favorite ceramic supplier (or one of the usual suspects of online ceramic stores). In addition to the pyrometer itself, you will need a ceramic grade thermocouple. The included thermocouple with many inexpensive pyrometers is a little plastic coated nub that might be good for checking the temperature of a bowl of mashed potatoes, but useless in a kiln. Some of the ones from a ceramic supplier will include a proper thermocouple, while the ceramic grade thermocouple is an accessory purchase with others, but at least a ceramic supplier will have them. The big river in south america dot com has lots of cheap pyrometers, of course, but you're on your own as to what else you need.
  20. I have not tried that specifically, but my general knowledge of ceramic glazes is that would not work. The raw glaze needs to adhere to the surface of the ceramic body, and if there is anything in between, such as dirt, dust, oily residue from fingers, stray wax from the bottom, etc., the glaze will shrink back from that dirty spot as it melts. I would think the gesso will do the same.
  21. The probable reason it is rated to only cone 6 is the blank ring in the middle. That adds volume but no additional heat. The blank ring can be removed to improve the watts to volume ratio, but that would limit the size of things you could fire.
  22. An issue with the GG and a Shimpo wheel is that the mechanism of the GG is that counterclockwise torque (assuming a typical US counterclockwise wheel) on the base of the GG causes the inertia of the sliding top to press clockwise with respect to the base, which causes the arms to move inward on their spiral tracks. This is exactly the same as the initial tightening on the ware while putting it in the center. This keeps it gripped during the trimming. However, the Shimpo wheel stops very quickly when you back off the pedal, much faster than other brands. As a consequence, the top of the GG tends to keep some of its counterclockwise momentum with respect to the now stopped base, which has the effect of very slightly loosening the arms. It is at that point where the ware moves off center, but you probably didn't notice it happening.
  23. 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
  24. Terry Fallon is a wonderful fellow crystallier who was a gas plumber in his day job. He had some serious health issues, and so is not active anymore. His Fallonator was a ConeArt kiln with a standard Bartlett controller that used controller #4 to trigger solenoids to start a flow from a small propane bottle together with a compressor to inject air, all kept in proper balance by an automotive O2 sensor. The objective was to fire to peak in oxidation so the zinc in the crystalline glaze would not volatize, and then start reduction during the the crystal growing phase at lower temperatures. He did not make many of them before his health failed.
  25. Please be aware that the "kiln model LT-3K" is not the model number or brand of the kiln. The kiln sitter is a manual control device commonly used by numerous kiln manufacturers. There were a couple of different ways of putting the kiln sitter together, and each manufacturer used the particular model/style that fit their kiln design. LT-3K is one of them. The actual kiln manufacturer, model number, and electrical specifications should be printed on a metal plate attached somewhere on the side of the red switch case. That is the important information that a buyer will need to know.
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