Dick White
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Posts posted by Dick White
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1 hour ago, Hulk said:
My Pop was a multiple year singles Regional champ (in his age group) back in the 2000s
I'd guess the optimal force could be somewhat involved, for (like swimming) the early part of the stroke, where we're weaker, is still important - setting up the vortex/vorteces for later, where we're stronger. Also, entering cleanly, minimum loss of momentum via splashing, and shedding bubbles quickly matters. Slipping out of the vortex with minimal hang up at the end of the stroke and getting out cleanly matters...
Tom, mostly yes. The early part of the drive is actually the most powerful because it comes from the legs. The later parts come from weaker muscles of the core and arms. But yes, maintaining momentum after the initial push with the feet is important. Water (and air) resistance increases by the speed squared, so speeding up to regain the momentum after slowing down is much harder. And an interesting factoid about that vortex at the end of the stroke - that is actually a sinkhole of wasted energy that was not applied to the forward motion of the boat. Some is unavoidable due to the lateral motion of the blade through the stroke, but the puddle needs to be minimized as much as possible. Big puddles = lousy rower. You should follow your dad, it's another fun way to waste time, as if clay isn't...
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Not pottery, but one of my other life distractions is rowing (in one of those Olympic-looking long, skinny, barely ass-wide boats with long oars). Someone in one of the rowing groups I hang out it asked an AI bot to describe how to achieve the optimal force curve during the rowing stroke. The bot went on for several paragraphs of blather, and ended with the suggestion you should talk to a knowledgeable person such as your coach.
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Two thoughts"
I am assuming you would be constructing your own digital controller from a raw Bartlett controller and all the associated parts. As you have discovered, there are no pre-built wall-hung controllers that support a 4-wire power supply. Yes, you could remove the kiln sitter and control boxes with the switches and directly connect the controller's relay outputs to the kiln elements. That would require building new or adapting the old control boxes to appropriately contain the connections, and lengths of appropriate cable from the digital controller to the kiln. I have done this with several manual kiln conversions, though not with a 4-wire Paragon, but being familiar with the Paragon wiring diagrams, in theory it should be possible. You will need to be facile with wiring diagrams, basic metal working, some electrical skills, and understanding of element resistance/amps/etc. It's not a job for the faint of heart.
As for your 50 amp circuit, the ampacity of the circuit should be at least 125% of the total rated ampacity of the kiln (including the extension ring if you make that a permanent part of the kiln), but not more than 150%. You didn't say what the rating plate(s) on the kiln show (i.e., is the 30 amps you mentioned the actual kiln amperage (including the extension) or just what somebody told you was what the kiln needed), but you can do the calculations yourself. If the ampacity of the circuit needs to be downrated for this kiln, you can achieve that simply by putting an appropriate lower rated breaker in the panel. There is nothing wrong with having heavier 50 amp wire servicing a 30 amp breaker. The heavier wire will be fine. Just don't do it the other way with a heavier breaker servicing lighter wire. Be aware that the limit of this 50 amp circuit is a 40 amp kiln. The larger plug-in kilns on the market are all 48 amps and require a 60 amp circuit.
- Bill Kielb and Jeff Thompson
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Thank you all who chimed in. I think I have enough EPK on hand in both studios I work in to get us through any temporary shortages. I'll just keep an eye on inventory availability at my local supplier and grab a bag when they have it sooner than I might actually need it just so I have it. The Gerstley situation is more of a problem. I rejoiced 10 years ago when Laguna bought the remains of the mine yard and processed it into what was loosely described as a "lifetime supply," or at least the rest of my short lifetime remaining in the pottery business. But wow, 3 years remaining supply is not long. Yes, I can still get it at crazy expensive prices, but soon money will be irrelevant. I had set a summer project to recalculate and test all the studio glazes for 3134 in place of Gerstley, mostly to save the county some money. 3134 (or any frit) has always been moderately expensive as materials go, but a bag of Gerstley is now almost 50% more expensive than 3134. A rough calculation of a year's glaze usage at the studio suggests I could save $500 a year using 3134. But now I see it is no longer just a question of money. I need to get cracking on this project before Gerstley simply is no more.
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Some N. America/USA oriented questions: This group being populated by the most knowledgeable of all the glaze groups I stumble around in, does anybody have the real story on Laguna and Gerstley (other than it has become crazy expensive)? There is also some noise about availability (or lack thereof) of EPK.
Just wondering...
dw
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Some rough technical calculations, for me in dumb English units as that's what we in the colonies still use despite the mother country having gone modern on us with the superior metric units... Your kiln has a surface skin area of about 650 square inches. If it is producing its rated 2kW, that is about 3 watts per square inch of surface area. The issue with kiln size and power is that as the kiln interior heats, the surface of the kiln radiates some of that heat to the air rather than keeping it to the ware. Looking at the range of US kilns made by Skutt and L&L and their advertised maximum cones, most of the models rated to cone 10 are generating 3.5 or more watts per square inch of exterior surface. Ones that are rated to cone 8 (i.e., typically large kilns operating at lower voltages) generally are 3 or less watts per square inch. We have a general rule of thumb that the maximum manufacturer's ratings only apply when the elements are in perfect shape, and for regular usage over the long term, one should downrate the kiln maximum by 2 cones, e.g., one should expect a cone 8 kiln to remain serviceable in the long term only to cone 6. So, your kiln should be able to go to cone 6 when everything is in good shape.
That's where we make judgements about "in good shape." The Orton cone table specifies that cone 6 should bend at around 1220℃ when the kiln is heating at a constant rate of 60℃ per hour for the last 90-120 minutes of the firing. During the last 2 3/4 hours of your firing, it was averaging about 45℃ per hour, and in the last 40 minutes, it was only making 24℃ per hour. So, yes, it is struggling with an empty kiln. It will be worse when you put some ware in there.
And regarding the resistance reading, Ohm's Law calculations suggest the kiln is producing around 2,175 watts, pulling 9 amps when on high.
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Can you tell us the dimensions of this kiln - outside diameter and height, and the thickness of the brick walls. That will help us estimate whether the wattage of the elements will make cone 6 with reasonable ease.
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Can you post a well-lit picture of the inside of the kiln. That will help us identify if it is ITC or ordinary kiln wash. Also, can you take a picture of the electrical rating plate that is on the side of the kiln or the control box. You say it was used for glass and has never been fired above 1200℉ - perhaps it was designed only for glass and would not be capable of the higher temperatures of ceramics.
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41 minutes ago, Skydve76 said:
Well that have different strands etc. assume they are both black.
The description of the one on the left sez color is green. I don't think the number of strands in the wire matters, it is 12 AWG.
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43 minutes ago, Skydve76 said:
Which one of these do you think I should get for wire? This place sells by the foot no min order, the other place wants 125ft min!
Get the black one. Green should used only for ground.
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8 minutes ago, Skydve76 said:
Not sure if this is the correct place to ask, but can you recommend some clay and glaze that will work well with my setup? I see amazon sells quite a bit but lots of options.
Others may have different opinions, but I would not get clay from Amazon. Not that Amazon sells bad clay, but if possible you will be better served to find a clay store near you and develop a customer relationship with them. They will be able to guide you to appropriate clay bodies and glazes that will work together.
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1 hour ago, Skydve76 said:
So after all this, I still dont know how to use the klln
Is this kiln useful? Just want to make pots and then glaze them.
Yes, it will be useful up to midfire cone 5/6. So, how to "use" it? After you get it all cleaned up and running again, load the kiln sitter with the appropriate mini-cone, push the white button to set the sitter on, and then progressively turn on the brown switches over time. Each switch will add 1800 watts of heat, until all four are on for full heat. Some follow a schedule of the first hour with just the bottom switch on, then add a switch every hour. For a bisque firing, stay with just the bottom switch on until no more moisture is coming out the peep holes - hold a glass jar over the open peep and any moisture still coming out of the greenware will fog up the glass.
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Ok, that gives us some useful technical data. Applying the math of Ohm's Law in reverse to the rating plate - 4 equal elements pulling a total of 30 amps or 7200 watts at 240V, each of the 4 elements in perfect shape should be 32 ohms. That's pretty close to what you are showing on your meters. Now, taking that to the next step in guesstimating kiln performance, your Gare 2318 is approximately the same size as a Skutt 1018 or an L&L e23S. Those each produce around 9500 watts, or about 30% more heat than your kiln. Add to that, your older kiln probably is made with 2 1/2" brick vs. the current standard of 3" brick, so your kiln will lose more heat to ambient radiant losses. Consequently, my rough guess is that cone 6 will be its maximum capability, and even that will be hard work for the kiln.
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There is another theory about pinholes in commercial brushing glazes that is not widely discussed. That theory holds that when the first coat of glaze is brushed on, there are likely to be some small voids in the coating that are nearly unnoticeable. When the second coat is applied, it doesn't get down in these little voids, creating air bubbles where the second (and later coats) cover them up. Late in the firing, the melt finally gets down to that layer, and the bubbles erupt out through the glaze. Just an idea. If you don't have trouble with this clay body pinholing with dipping glazes, you probably can eliminate the body as the problem and look towards your brush application.
- MKG001, Babs and Magnolia Mud Research
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It appears that the pits go all the way through to the body, so the bubbles are starting there. You say the body is rated for cone 5-10. That means it is immature at cone 5/6, not mature until 10. An alleged wide firing range is one of the unfortunate fallacies perpetrated by the clay industry. My guess is that there is still stuff outgassing from the body at cone 6. If you are using a kiln with a digital controller, you can try a controlled cooling to allow the glaze to heal over any bubbles that are coming up.
As for the unexpected color, I'm not familiar with that glaze.
- Kelly in AK, Hulk, Piedmont Pottery and 1 other
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1 hour ago, neilestrick said:
... nor have I seen a 3 wire plug with a neutral and no ground, but hey that doesn't mean they don't exist...
Back in the day, dryers (with a 10-30 plug) and stoves (with a 10-50 plug) used 240V from the two hots for the heating circuits while the controls and interior lights used 120V from one of the hots plus the neutral. Apparently, independent grounding wasn't a high priority back then for those household appliances as chassis grounding was permitted through the neutral, though the really old120/240V kilns that we sometimes get involved with here all use proper 4-wire grounded circuits. In '96, the code changed to mandate separate grounding everywhere, hence the change to 14-30 and 14-50 for all new dryer and stove circuits. There is still a neutral for any 120V components in the dryers or stoves, but now there is a separate safety ground. However, you can still get a 10-30 cord for a new dryer if you are installing it in a grandfathered pre-'96 house.
I too suspect it is unlikely that this kiln has anything in it running on 120V (that would need the neutral), and therefore should be fine with a fresh 6-50 power cord, with the circuit in/on the wall running a straight double 240V 40A breaker and 8 /2-with ground cable to a 6-50R outlet.
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Is it "struggling" to get to cone 04, or does controller need calibration so that it turns itself off at the proper temperature? If the glaze firings are reaching the expected results according to witness cones, leave the overall thermocouple offset alone and set a cone offset for cone 04. Instructions for this should be in the user manual.
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The island/mound will occur when the proper amount of dry plaster has been added to the water in an appropriate size and shape bucket. However, an island/mound may also occur with the incorrect amount of plaster and /or an inappropriate size or shape bucket, and so the mere appearance of this infamous island/mound should not be regarded as the proper mixing ratio. The only accurate method to get a strong plaster mold is to add the exact weight of plaster to the exact quantity of water as specified by the plaster manufacturer. The ratio of plaster to water is different for plaster of paris vs. pottery #1 plaster.
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Age in years is less of an issue than the number of times they have been fired to maximum temperature. At the community studio I manage, the glaze kilns rated to cone 8 that are constantly fired to cone 6, we get about 75-80 firings in a year before they are too worn to finish. The bisque kilns are still firing to cone 06 on the same elements for 10 years now.
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... another link from the Paragon website. Paragon bought the Duncan line when they went out of business. https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/LX851_Duncan_Energy_Saver_Owner_Manual.pdf
dw
- Hulk and Bill Kielb
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Many studios use plastic dry cleaner bags to wrap the fresh greenware. I have not been in a dry cleaner establishment in the 15 years since I retired from my real day job downtown, so I ask students to bring in theirs. One studio I work with went to whatever supply house and got a full 1000 piece roll just like the cleaners use; we've been working that roll for 4 years and still have half. The dry cleaner bags seem to have a reasonably predictable permeability for drying by next class time, and they are thin, light, and flexible so the ware is not smushed when wrapping it. The problem is that few students take the time to cut the full bag into appropriate size pieces, so the work-in-progress ware shelves are loaded with single mugs on 12" square boards wrapped in an entire bag (and because it is still a bag, it's a double layer draped over the mug). And then some Helpful Hanna/Harry brings in an armful of garment bags scavenged from the department store when the stock clerk was unwrapping and setting out the spring fashions - a completely different type and weight of plastic. And don't get me started on the empty clay bags that show up in the bin. After all, plastic is plastic, isn't it? Well, no, as you point out there is plastic and there is *plastic*, not all the same.
All that said, when the bin is running low (with 125 students cranking out production), I have picked up a package of cheap lightweight painter's drop cloth from the local blue or orange big box, like your suggestion (except I get the lightweight 3-pack, yours is midweight). I've also noticed that the community center uses the cheapest lightest thinnest trash bags, so I have raided the janitor closet.
Carry on, we are comrades in arms...
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Measuring the resistance of the elements is the most accurate way to determine if they are sufficiently worn that the kiln will have trouble heating, and thus the elements should be replaced. However, if one takes a close look at Ohms Law that mathematically relates volts, amps, resistance, and watts, amperage is an inverse proxy for resistance. Skutt kilns manufactured after 2006 all contain a current sensor that can measure the amperage being pulled by each section (some from before this date might have one too). This amperage measurement is built into the controller diagnostics and can be retrieved without opening the control column. If you do not have a copy of the user manual, you can download one here - https://skutt.com/skutt-resources/manuals/kilnmaster-manuals/. The original specification for the amperage of each section of a 1018 is 20 amps (both sections are the same). If the amperage readings are 18 or below, the elements are worn.
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The report at the time from Laguna was that they picked up 3,000 tons of the stuff from the mineyard. That's a, well, I shouldn't say the word, but it is a lot. My guess is greed, but what do I know?
Is this kiln useful? Just want to make pots and then glaze them.
ChatGPT can be very misleading
in Studio Operations and Making Work
Posted
I agree, AI will not replace those of us who fully understand our particular niche, but that won't stop them from trying... until their reliance on AI dumps them someplace they don't know how to get out of, if only because they don't understand how they got in there. Sorta like the stories of a few years ago of people driving into swamps because that's what Google Maps told them to do.
And back to @Kelly in AK's unrelated question... Yup, about as unstable as can be. It's not a perfectly round cross-section, we do have a nearly imperceptible keel. The stabilizing force is the same as The Great Wallenda - his long balance pole. Our oars stick out 9' on either side. As long as we keep our hands (on the oar handles) moving in the same plane parallel to the water, the oar shafts and blades will also form a line parallel to the water, and we don't flip. Deviate one inch with either hand, and it's all over. We have a semi-serious joke - there are 2 kinds of rowers: those who have been swimming and those who will be going swimming soon. (Yes, I have been swimming, several times.)