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Bill Kielb

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Everything posted by Bill Kielb

  1. @bijoy Actually since it’s only for marking fabric, do you even care about the impurities? Anyway, I can’t tell from your picture if that’s better or worse or the same so if better I guess I would go for an hour hold and so on if better still. At some point I think you need to figure out what it will take to fully remove the organics temperature and most likely the hold time as in hours and see if this still works for you. The previous question of cleaner kaolin comes to mind as well. BTW, my mother always used bits of soap when she ran out of Taylor’s chalk. She would always gather the soap bars that became too small to wash with. This was fifty plus years ago though and the economy was essential in those times.
  2. This was an interesting read http://www.madehow.com/Volume-1/Chalk.html how conventional chalk and pastel chalk is made. Calcium carbonate and or calcium sulphate. Clay consistency is mentioned but it looks like it is done without clay and at much lower temperatures. Maybe worth reading,
  3. That makes a bit more sense, but I would get the electric portion solidified for sure. I assume you meant 233 v at the main not 433 v. 233v would be bad though as it will automatically reduce your capacity further. Electric services in the US are pretty reliable. Voltage fluctuations occur but ought to be pretty rare and reasonable in range. When they are not, there is almost always a real reason. None of your measured stuff is consistent with what we would expect. Elements that should draw 35 amps should draw less than 35 amps with lower voltage yet yours draw 38 amps. So either a measurement accuracy thing or you will find a reason for the inconsistency. With less wattage to do the job, dense loads may take excessive time in a large kiln as well. If there is not excessive drop in the wire, it will help but is also likely not the cause of your issues so bigger wire will be better but not likely the cause. An interesting possibility would be they sent 208v elements, your first firing fired somewhat ok but the elements overproduced as 230 plus volts and are possibly worn to this current level. It’s easy to mix up voltages, current etc… try and be exact, measure the element resistance with reasonable care. 240 volt elements all in parallel operation should read 6.86 ohms, 208 v elements all in parallel operation should read 5.15 ohms. Not a giant difference when measuring, consistency and precision in measurement will move you in the right direction, and paragon hopefully will be asking for these measurements. Suggesting recrimping elements when voltage drop is excessive is a bit of a strange ask actually if they knew the system voltage was dropping. An infrared thermometer is pretty good at spotting overheated connections btw.
  4. Well that’s too much drop for sure so where is the drop? CAUTION Live testing requires proper safety practices, when the kiln is firing do you have 240v at the breaker or does it drop there as well. If it does, check the breaker, is it hot? If not, then the voltage drop is in the wiring between the kiln and breaker which points to a bad connection or undersized wire. So this is a 3-4% drop which might be enough to cause you trouble, normally a cone ten kiln has trouble at a 10% element change so I would definitely remedy your electrical situation this being a cone 8 kiln and starting off with a 4% disadvantage. If rectified by an electrician I often specify 1% or less drop for kilns. The 3% rule of thumb is just too much.. The chart below shows what the manufacture recommends for your kiln with respect to wire, breaker, plug …. So 50 amp circuit breaker and likely #4 wire. The distance (40 ft) is the two way wire distance, so if 20 ft one way, then its 40 ft.
  5. I believe they will take time and temperature to burn out. Everything I read says no major clumping till 700c so, I think you could test lower temperature for more time, or move on up towards 700c If adding time does not Help. Remember, I said it takes hours to clean the stove to white ash at about 500c. So if it were me and since you have no clumping issues at 600c, what happens if you hold for 2 hours, 4 hours? If it’s an improvement then continue on that path. If it’s not enough then you will need to go higher in temperature and / or lengthen your time. You might consider Plaster of Paris or cornstarch easily make nice chalk as well. No kiln required. Plaster of Paris video: https://youtu.be/r07-m70t34A
  6. Yeah, I am not following actually.. you are using this clay to make something and it needs to be fully dewatered or calcined but you would like the organics to stay? Sounds like you will need to experiment with time, temperature etc…
  7. Seems like the opposite of what one would want to do. Not sure why you wouldn’t want to burn out the organics?
  8. 550 c may get it done, just more time may be the secret and safest thing to try. I think even my self cleaning oven needs a few hours time to turn the simple organics to white ash at about 500c. I would try a 30 or 40 minute hold first, or even a slower ramp, say 100c per hour, then if no improvement gradually increase temperature. I see references to 630c as a common temperature to dewater. I don’t think you will see significant clumping issues until above 700c. So in the end, likely a balance between temperature and time you are willing to wait. As always, test to know for your clay, kiln, firing technique………etc If you do test, try and return here to post what works for you. It may help someone in the future.
  9. Likely organics (Carbon), why are you firing at 550c (cone 024 ish) for 20 minutes? Just curious, what s intended with firing at this low temperature, removal of combined water?
  10. A suitable replacement would be an infinite switch, same as made for electric stoves. If it gets to that point post your kiln schematic and a suitable replacement can be found. Getting the replacement from Cromartie would be best and easiest. If they publish the replacement part manufactures number other sources can likely be found as well. I doubt Cromartie makes their own. Those types of switches have significant moving parts inside, so I would plan on replacing that one sooner than later as it looks fairly overheated and annealed by the heat IMO. Definitely replace the burned wiring or cut it back significantly to very nice shiny new looking wire.
  11. Sorry, saw this and forgot. Condensation …… so the thing to know is when warm moist air hits something cooler than the dew point temperature it condenses on the cool surface. Sort of like condensation on a cold glass on a hot humid summer day. So for a tin shed where the steel cools more quickly than the air, generally the inside surface is insulated to keep it from getting cool enough (dew point temperature) and a vapor barrier is installed in front of the insulation. The vapor barrier is intended to ensure no water vapor can creep through the insulation and condense on the cold steel behind it. Many types of rigid insulation can be their own vapor barrier as well usually requiring taped seems. Anyway, the basics are vapor barrier always warm side, insulation, then the cold surface. Hope that helps.
  12. The Norman kilns have been traditionally table top in the 48 and 33 series. Popular for jewelry, paint, small clay. You might ask for a picture of the equipment and the kiln equipment tag first and check what temperature it will fire to.
  13. Line blends for colorant work for most, progressing from light to dark so one test can generate many shades from one small sample. Hey don’t forget mason stains.
  14. These posts are from 2020 so you want want to DM the original poster. As far as on target a glaze fire can go more like 6-8 hours or about 450 degrees per hour with the last 200 degrees of the firing at about 110 degrees per hour. So for the Bartlett V6cf cone six fast firing, likely 6-8 hours. As your elements wear your kiln will not be able to keep up and your glaze firing times will grow towards that 16 hours you seem to be at.
  15. Just a couple observations FYI - Clay goes through quartz inversion up and down. For a glaze firing if your load has stopped let’s say within 300 degrees or more of its firing cone temperature then little heatwork was likely done so refiring generally is not an issue. For bisque you can bisque fire pretty much as many times as needed within reason. Finally to make your cone drop at the temperature advertised on the cone chart, fire at the appropriate speed per the chart for the last 200 degrees. So for cone 6, center column (108 degrees per hour) fire to 2232 Starting at 2032. If you can fire per the chart, you stand a good chance at nailing your cone. Holds at top temperature can cause issues, do them only when you have a real confirmed reason to.. Bisque firing only sinters the clay together so not much melting. Bisque firing generally take longer to burn everything out so time at temperature is important. Many bisque firings range from 10-12 hours just to be sure to remove all organics. Quartz inversion just happens, up and down. Clay is tough, it generally can take it. Not much we can do about it. Typical glaze fire speeds 400-500 degrees per hour Typical Bisque speeds approximately 200 degrees per hour Hope that gives you some ideas for future use.
  16. Stroke and coat is advertised as such and I have used it for overlays, etc…successfully to cone 6 it has been around for many years. Google Mayco stroke and coat.
  17. Maybe someone with direct experience will answer but since this is a commercial glaze we have no idea of how much clay it might contain and if it is naturally deflocculated due to sodium. I suggest a good read for this https://suemcleodceramics.com/how-to-fix-a-hard-panned-glaze-with-epsom-salts/ You likely will end up using Epsom salt a little at a time to re suspend the glaze. Since bentonite can generally be added up to 2%, you might settle on 1% addition because you will never know the actual clay content, then flocculate with minimal Epsom salt as a start. Hopefully someone has direct experience with this commercial glaze for a tried and true solution. Actually a call into Amaco probably gets you the most tried and true solution for this glaze. I am sure they have seen it before.
  18. Not likely, the bend matches the radius of the motor pivot. Tensioners are usually only meant to set the tension, then the remaining bolts of the assembly are tightened so it doesn’t wobble or move removing the angular load from the tensioner. I would suggest: Check the condition of the belt, proper belt alignment (belt running true between the drive and driven pulley), and tension on the belt. Then, check all remaining bolts are appropriately tight so the motor assembly does not wobble.
  19. If you look at the label (equipment tag) posted above it appears Gare mentions directly what the maximum firing cone and temperature is for that particular model. 3 rd line from the bottom. You may find your label tells you the kiln max firing temp, as well, read all the way through it is easy to miss embedded text.
  20. You need an ohm meter and there are several videos on testing elements. All work done with Power off. Not a bad thing to own and be able to do simple tests.
  21. IMO Post pictures here before firing.
  22. If it helps we found color and thickness to be a primary cause. In our case we needed a tested glaze that worked pretty much no matter how the artist wanted to paint it else be accused of stifling creativity! Hence the glaze solution. I think I only increased the boron a few points, so .15 to .19ish. Marcias matte is on glazy if you want to double check what it was brought up to. Anyway, IF this is your issue folks have been successful at adding a tiny amount of boron fritt or GB to their underglaze colors prone to this. Tiny amount seems to be key else the glaze chem locally is a mystery. Hope that helps. As usual tesssssst.
  23. Same relay, so that is good, right form. The actual moveable contact on the new one has overheated without a sign of the terminal overheating which means either it was defective from the factory and misaligned or lots of load went through it. I would double check the wiring and element resistance as wired to be sure that 25 A or more continuous wasn’t going through it. If not, then it likely came misaligned and overheated during firing. IME it’s rare to see them melted without the melting occurring right at the connection first. The moveable contact on this one looks annealed. Definitely worth thorough check IMO before dropping a new one in.
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