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  1. Maybe I can try a slower climb to Cone 6. There are so many variables. The good news is I only have to figure out what works one time, and then the issue should be solved.
  2. Thank you for your encouragement Bill.
  3. As with some things in pottery solving one issue has raised another. The pinholes are gone, but the slower cooling has affected the look of the glaze quite a bit in an unpleasant way. I would like some advice. Should I try to fire to Cone 5 and hold for 20 minutes with no slow cooling program, or should I do new test tiles with the Cone 6 temp and the cool down program? My witness cones show that the kiln may be slightly over firing at Cone 6 since the Cone 7 cone dipped to horizontal on all 4 shelves in the most recent firing.
  4. After trying lots of things that did not work to eliminate pinholes (bisque to cone 04, applying glaze thinner, applying glaze thinner, etc) I finally have solved the pinhole problem. I am using a ramp down temperature program after firing, decreasing the temp 150 degrees per hour until the kiln reaches 1500 degrees. The kiln load that came out yesterday had no pinholes. Yay!!
  5. Mark, thank you for your suggestions. I will try what you have suggested.
  6. The two pictures above are typical of the pinholing I am getting.
  7. The pinholing occurs primarily on the inside of the bowl but the location varies with no real consistency. Many of the bowls only have a single pinhole which sometimes is not very visible. I have been brushing the bowl with a dry cloth before glazing, but I will try using a damp sponge or even the dunk method you mention. The glaze is the consistency of heavy cream, so perhaps adding water could help? I will add some pictures tomorrow. Thank you for your suggestions, Pres.
  8. Thank you xinyao. I will try what you suggest, using a damp sponge to wipe down the bowls before I glaze them.
  9. I am slow bisque firing Standard 553 clay to cone 06, painting on 4 coats of Amaco glaze and then slow glazing to Cone 6 with no soak. Now that I am aware what a pinhole is I am concerned. I have fired 79 bowls and 27 of them have pinholes. I have fired 112 plates and none of them have pinholes. A few questions... is the pinhole pottery foodsafe? Why are bowls getting pinholes but not plates? My application thickness is the same. Would bisque firing to cone 04 help? I am firing in an L&L e23t kiln with a bottom vent running the whole time through firing and cool down. The peephole plugs are in the whole time. Any insight would be greatly appreciated. My dipped glaze bowls of which there are 22 are not part of the 79 referenced above) have no pinholes. If I can’t figure this out I am going to stop painting on glaze and only dip, but the colors of the painted bowls are awesome. Thanks in advance for any help!
  10. Thanks Mark and Min. I’m going to do the freezer mug with boiling water test tomorrow. I did a room temp test tonight, and it worked perfectly.
  11. Thank you both so much for your quick, insightful replies. Hulk, I have a white glaze I will use in the future in my mugs. Bill, I will suggest using slightly cooler water for the reasons you mention. Thank you both!!
  12. I fixed two potential issues. When I replaced an old element I twisted the wire counter- clockwise around the terminal instead of clockwise. I also had overstretched two elements such that there was sagging between some of my element holders, so I replaced those elements. Since I made those two changes the kiln has been performing perfectly.
  13. This reply is long overdue, but I wanted to report back. Thanks to all of your great advice and a lot of help from Neil Estrick, my kiln is dialed in and firing perfectly. I really appreciate this community.
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