Susan McHenry Posted November 24, 2018 Report Share Posted November 24, 2018 I work with red earthenware clay and decorate with white and colored slips at the leather hard stage. From time to time, I have issues with the slip peeling after the bisque firing (cone 04). Does anyone have any insights into why this might be happening? In the past, I’ve tried other slip recipes, but this doesn’t seem to make a difference. Link to comment Share on other sites More sharing options...
liambesaw Posted November 24, 2018 Report Share Posted November 24, 2018 You let your pieces get too dry before putting on slip. I apply slip while the piece is still leather soft, if the clay is able to pull moisture out of the slip it will separates or crack. I have tried spraying a piece that's just past leather hard with water before adding slip and it still cracked and peeled, so I don't know if there's something you can add like cmc gum that will make it stick better or not. Another issue may be a difference in shrinkage rate between your earthenware and the slips you're using. Link to comment Share on other sites More sharing options...
Babs Posted November 24, 2018 Report Share Posted November 24, 2018 As above . Are you making your own slip? If so lessen amount of water and a a couple of drops of deflocculant to get to desired state for brushing. State of dryness of pot is important. I brush the entire pot with water before applying , makes it easier to lay the slip on. Link to comment Share on other sites More sharing options...
Susan McHenry Posted November 25, 2018 Author Report Share Posted November 25, 2018 Thanks for the feedback. I use techniques similar to many working in red earthenware (Victoria Christen, Ben Carter, and Martina Lantin, for example) where I dip the pot in thin white slip and then layer colored slips on top of that. Perhaps you are both right about the need for a deflocculant so I don't have to use as much water in my white slip. I just ordered some and am eager to see if this resolves the issue. Thanks so much! Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted November 25, 2018 Report Share Posted November 25, 2018 I know for a fact Martina Lantin uses deflocculated white slip as a cover. Sat in on a workshop with her last year. Link to comment Share on other sites More sharing options...
Rex Johnson Posted November 27, 2018 Report Share Posted November 27, 2018 I tried using a Laguna Glacier White porcelain slip on my cone 10 (B-MIX) clay pieces this year with some good and bad success. The bad success were the pieces that I had brushed and then fired (Olympic updraft) that has real uneven firing and the pieces where close to flames. They peeled and flaked. The good stuff was all sprayed evenly when leather hard or near dry and fired in my downdraft kiln. Only a few pieces close to the bagwall flaked... I think at least in my case, even application and attention to placement in the kiln is essential. Sprayed piece when green... cone 6+ with clear cone 6 glaze etc... Link to comment Share on other sites More sharing options...
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