Katarina Posted February 9 Report Share Posted February 9 Hello everyone, I’m looking for some advice since I’m having trouble with my transparent glaze. I’m using a transparent glaze over slipped ware but I’m encountering pinholing, tiny bubbles in the glaze and some opaque patches (glaze too thick?). I’m making my own slips by slaking down my clay and adding 10% body stains. The slipped surface once bisqued isn’t as smooth as just regular thrown clay, so I was wondering/reading if I should wash my bisque ware before glazing or wipe with a damp sponge so the bisque would absorb the glaze better and get in all the little uneven bits? I also read to try a drop and hold firing/slow cooling. So I fire to 1260’C, dwell for 10 mins, drop down to 1220’C and hold for 15 mins. Should I only have transparent glazed pieces in the kiln or can there also be other glazes present? Any advice on how to achieve a clear and smooth transparent glaze welcome! Thanks! Quote Link to comment Share on other sites More sharing options...
davidh4976 Posted February 9 Report Share Posted February 9 Is this a glaze that has previously worked well for you and suddenly gone bad, or a glaze that has had this problem ever since you started using it? Quote Link to comment Share on other sites More sharing options...
Katarina Posted February 9 Author Report Share Posted February 9 This glaze was working fine on tester non-slipped pieces, no pinholing although now on closer inspection I can faintly see the tiny bubbles as well, slipped my eye since they show better on darker pieces. So I only just started testing this glaze out, showed promising on non-slipped pieces and then resulted in very pinholing surface on slipped testers. Wondering if this glaze and the pigmented slips are maybe not a great fit? Quote Link to comment Share on other sites More sharing options...
Wayne2 Posted February 9 Report Share Posted February 9 (edited) You don't mention if the glaze is a commercial one or one you make yourself? Tony Hansen (digitalfire.com look at the glossary for Drop-and-Soak Firing ) says one can drop 100 -200 degrees to the hold dependant on the glaze and one has to experiment to get a fit to the glaze. We have been using 100 degrees and that has helped our glaze surfaces. The larger drop probably won't negatively affect other glazes (other than increasing matteness of matte glazes). That being said, the loss of EPK and substitution of Tile#6 or Diamond has increased bubble production in the clear we have been using for several years now and thicker sections are more impacted by those bubbles and they turn the glaze whiter with less clarity. Changing that drop will likely help. PS You also didn't mention if you use cones to check your controller, what kind and your firing rate in the last step. Depending on your controller/kiln you may be firing a bit high, We have seen what seems to be a bit of correlation with fewer bubbles on shelves with lower temperatures and comments on another link on these fora seem to suggest that may be another thing to explore. look at the "holds at end of firing" thread in Equipment Use and Repair Edited February 9 by Wayne2 adding a reference to another thread in Equipment use and Repair Quote Link to comment Share on other sites More sharing options...
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