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Bill Kielb

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    All forms of constructionist pottery, education, analysis, design and repair as it pertains the ceramic arts community.

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  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. IMO Post pictures here before firing.
  10. 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.
  11. 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.
  12. I suggest Double check your element resistance, the relay rating, relay wiring diagram as it could be a defective one but it really is hard and very unusual to melt one that way. Reminds me of double pole relays I saw earlier this year that were the wrong form. That relay ended up as form Z but looked identical to form C https://community.ceramicartsdaily.org/topic/25213-duncan-kiln-not-reaching-temperature/?do=findComment&comment=203748
  13. If a flame is coming out of the pilot assembly some way then that often indicates the orifice or pilot deflector / mixing tube is blocked or partially blocked. The thought here is the reference to vent is the pilot primary air location where air should go in, so if true then maybe some blockage in the pilot deflector / mixing tube and not the orifice. Remove and clean the assembly, often spiders like to nest in the deflector tube. Gently clean everything, do not enlarge the pilot orifice, maybe pass a tiny needle gently through the hole if blocked or blow it out backwards opposite to the typical flow. If you post a picture, this can be confirmed with a bit more confidence. A weak flame will not keep the gas valve engaged. The pilot flame should be reasonably strong and blue and engulf the thermocouple. Wispy and yellow generally will not work consistently.
  14. If my suggestion of using 1 tablespoon of underglaze seems to be wasteful then by all means scale it down. Yeah, thinking about this a little further, if they are using 2oz bottles then a tablespoon is probably a bit much for a test sample as that is a 1/4 of their stuff and UG is likely expensive for them. I see lots of folks with 2oz bottles for variety in color and pints for base colors they use. Actually just running this in my head with the tablespoon of underglaze assuming about 65% is raw materials with a likely percentage of 20% or more clay already in the formula, this probably kicks the clay up another 20% or more using the teaspoon of epk so maybe scale this all back considerably as well to start the test.
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