dhPotter Posted December 6, 2016 Author Report Share Posted December 6, 2016 Min, A mug, just like the turquoise - same style same glaze combo, but this one works, it had been out of the kiln for a month in the pottery shop. Placed in a 170*F oven for 1 1/2 hours. Then placed in a stock pot with warm water to cover, covered the pot, brought to a boil, then simmered for 6 hours. Weight after oven - 492 g Weight after simmer - 502 g - that makes it 1.02%, right? for Laguna - Miller WC-607 #55 Clay the Avg. Water Absorption 1±% 1.9% Link to comment Share on other sites More sharing options...
Min Posted December 6, 2016 Report Share Posted December 6, 2016 Min, A mug, just like the turquoise - same style same glaze combo, but this one works, it had been out of the kiln for a month in the pottery shop. Placed in a 170*F oven for 1 1/2 hours. Then placed in a stock pot with warm water to cover, covered the pot, brought to a boil, then simmered for 6 hours. Weight after oven - 492 g Weight after simmer - 502 g - that makes it 1.02%, right? for Laguna - Miller WC-607 #55 Clay the Avg. Water Absorption 1±% 1.9% Nope, boiled weight minus original weight divided by original weight times 100 therefore comes to 2.03% absorption. But, this is for your glazed mug right? So, for an unglazed test sample (way this test is supposed to be done) the absorption could be.......? If a test with bare clay only came to 2.03% I would rule that out as the problem. Not sure we can do that with a glazed sample though. Watcha think? Was your sample mug made from the same lot number of clay as the weeping pots? Link to comment Share on other sites More sharing options...
dhPotter Posted December 7, 2016 Author Report Share Posted December 7, 2016 Yes, same clay. Trying for a glaze firing over the weekend. Have a bunch of test tiles already bisqued. Probably use 3 of these and fire in the glaze firing, without glazing. Then run the test again and weigh each individually. Thanks for the formula. Link to comment Share on other sites More sharing options...
glazenerd Posted December 8, 2016 Report Share Posted December 8, 2016 DH: Your two glazes are running 8.80 and 8.90 COE. On average stoneware runs between 5.75 and 6.00 COE. Getting your glaze COE down to 8.00 would not hurt any. Nerd Link to comment Share on other sites More sharing options...
Roberta12 Posted December 8, 2016 Report Share Posted December 8, 2016 DH, this really is a puzzle. Thank you for sharing all your info with us. I have only used the Turq matte as an overspray with other colors. I think I may do a little testing myself. But like Min said, perhaps it is a bad batch of clay? I think that happens? I had a couple of boxes from Aardvark that had rocks in it. Is it possible to get a different clay and try the same glaze combo? roberta Link to comment Share on other sites More sharing options...
Rebekah Krieger Posted December 9, 2016 Report Share Posted December 9, 2016 May I ask what the firing range of your clay is and what you fired it to? Sounds like a vitrification issue, Link to comment Share on other sites More sharing options...
Babs Posted December 9, 2016 Report Share Posted December 9, 2016 What dryness are you ribbing at, pos. Crack occurs then? Ping testing bisque Glaze stirred between dips...settling out of some ingredients ???? Link to comment Share on other sites More sharing options...
dhPotter Posted December 12, 2016 Author Report Share Posted December 12, 2016 Rebekah the clay is ^6 - Laguna #55 Miller WC 607 - the clay goes by these names. The glaze fir goes to 2190* F with a 15 minute hold. The cones got to tip touching for ^6 across all levels of the kiln. Cone 7 goes to about 1-2 o'clock all levels. Babs ribbing done at time of throwing the piece. It happens before the belly is put in and the rim is finished. The most interesting part is I have another mug, just like the ones that are leaking, with the same glaze combo that my wife drinks coffee from each morning. The mug also goes into an 1800 watt microwave for 1 minute on high. No problems. Thank You Link to comment Share on other sites More sharing options...
Babs Posted December 13, 2016 Report Share Posted December 13, 2016 rotten prob. good luck. Link to comment Share on other sites More sharing options...
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