lanniec Posted Sunday at 03:05 PM Report Share Posted Sunday at 03:05 PM I have been using Mayco Fundamentals with a clear coat for about 3 years. Yesterday I had a full load, used the same settings I always use, with the only difference being I have started to use an external fan on the controller board (on the external heat sinks) because I've had two glaze loads this summer that shut down because my kiln board reached 180 degrees. All pieces came out fine except for 3, which have no glaze on them. Do you know why this would happen? I've attached a photo of one of the pieces where there is no glaze left. It was glazed the same as the other two chickens. I've examined it carefully, there is no glaze anywhere, not even in the recesses. There were about 6 pieces each on two levels. All but 3 of the 12 came out fine. The 3 that lost their glaze were on the top shelf. But the others on the top shelf are fine. Thanks for you help. Quote Link to comment Share on other sites More sharing options...
Roberta12 Posted Sunday at 04:32 PM Report Share Posted Sunday at 04:32 PM @lanniec Was Basil a different clay? Quote Link to comment Share on other sites More sharing options...
PeterH Posted Sunday at 04:41 PM Report Share Posted Sunday at 04:41 PM Was Basil intended to have no underglaze? Are the other two without glaze also without underglaze? Quote Link to comment Share on other sites More sharing options...
lanniec Posted Sunday at 06:30 PM Author Report Share Posted Sunday at 06:30 PM All painted the same. Same number of coats, painted at the same time. The other two that the glaze/underglaze vanished were the same as the two glazed in the photo. In total, 12 glazed with Mayco fundamentals with a clear coat over the top. Same as I’ve been doing for 3 years. It’s really baffling to me! Quote Link to comment Share on other sites More sharing options...
Roberta12 Posted Sunday at 07:55 PM Report Share Posted Sunday at 07:55 PM @lanniec Back to my question, is all the clay the same? What is that clay? I live in Colorado and get my clay from Stoneleaf, do you? and what temp are you firing to? Do you think Elves snuck in and switched some chickens?? Just kidding, but I cannot think of a reason 3 of them would do that. I have had underglaze fade on pieces (pink, maroon, etc) but Basil doesn't even look shiny! Quote Link to comment Share on other sites More sharing options...
lanniec Posted Sunday at 08:51 PM Author Report Share Posted Sunday at 08:51 PM I also get my clay from Stoneleaf. Laguna Mid-fire clay. I’ve been using the same clay, same glaze, same kiln, same firing time and temp (to 2167 with 15 min hold) for 3 years. The only difference is that I have an external fan on for the first time to keep my board temp below 180. It’s so strange that only 3 of 12 did this. Nothing shiny on any of the 3 and the other 9 are great. They look like I fired them without using glaze. But I glazed all 12 the same. It is as if the glaze vanished. I have an email to Mayco. Roberta12 1 Quote Link to comment Share on other sites More sharing options...
Babs Posted Sunday at 10:21 PM Report Share Posted Sunday at 10:21 PM Hi, tired potter? I have v late at night early morning glazed only one half of bowls ..light not the best, brain fatigue...if rest of kiln perfect, human error? But worth investigating. High Bridge Pottery, Kelly in AK, Min and 2 others 5 Quote Link to comment Share on other sites More sharing options...
PeterH Posted Monday at 08:10 AM Report Share Posted Monday at 08:10 AM (edited) 16 hours ago, lanniec said: All painted the same. Same number of coats, painted at the same time. The other two that the glaze/underglaze vanished were the same as the two glazed in the photo. A weird glaze result is one thing, but it's really hard to believe that an under-glaze could completely disappear on firing. Let alone four different under-glazes: red, orange, black & light green. Sorry, but to err is human. Edited Monday at 11:27 AM by PeterH Min, High Bridge Pottery and Kelly in AK 3 Quote Link to comment Share on other sites More sharing options...
Roberta12 Posted Monday at 02:01 PM Report Share Posted Monday at 02:01 PM 17 hours ago, lanniec said: I also get my clay from Stoneleaf. Laguna Mid-fire clay. I’ve been using the same clay, same glaze, same kiln, same firing time and temp (to 2167 with 15 min hold) for 3 years. The only difference is that I have an external fan on for the first time to keep my board temp below 180. It’s so strange that only 3 of 12 did this. Nothing shiny on any of the 3 and the other 9 are great. They look like I fired them without using glaze. But I glazed all 12 the same. It is as if the glaze vanished. I have an email to Mayco. Is the clay Whitestone? Quote Link to comment Share on other sites More sharing options...
Roberta12 Posted Monday at 02:04 PM Report Share Posted Monday at 02:04 PM Just now, Roberta12 said: Is the clay Whitestone? I really am puzzled....Same underglaze, same clay, same everything other than the addition of the fan on the controller. Did you put cones in this load? Quote Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted Monday at 03:09 PM Report Share Posted Monday at 03:09 PM You mention that all the pieces that came out like this were on the top shelf. Is there a possibility the top shelf was cooler than the rest of the kiln, and this glaze is only sintered and therefore still opaque? Counterintuitively, the top shelf of the kiln can often be a bit cooler than the bottom. If so, I’d refire them in the middle or bottom of the kiln and see if that sorts them out. Quote Link to comment Share on other sites More sharing options...
Babs Posted Monday at 10:16 PM Report Share Posted Monday at 10:16 PM On 9/16/2024 at 12:35 AM, lanniec said: . There were about 6 pieces each on two levels. All but 3 of the 12 came out fine. The 3 that lost their glaze were on the top shelf. But the others on the top shelf are fine. Thanks for you help. @Callie Beller Diesel seems there were 6 pieces on that top shelf, three beautiful, three blah. Still betting on human error here:-)) but interested on out come. If O P had the nerve to break one flawed one , all may be revealed. Quote Link to comment Share on other sites More sharing options...
JohnnyK Posted Tuesday at 06:11 AM Report Share Posted Tuesday at 06:11 AM This is a trick question, isn't it? You just want to get some speculation going on something that just doesn't happen in the real world. Nice try...😏 Bill Kielb 1 Quote Link to comment Share on other sites More sharing options...
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