JMP Posted August 23, 2020 Report Share Posted August 23, 2020 Hi all, just joined and need some advice please.... I’ve been using Stoneware Special Fleck clay, painting with Amaco Velvet Underglazes and decorating with spots of Duncan French Dimensions before firing to Cone 04. I then dip in clear glaze before firing again. On the last 2 batches, just before dipping, a couple of the spots of french dimensions have fallen off, showing bare clay underneath (ie it’s taken the underglaze with it). After glaze firing some of glaze and underglaze has flaked off completely in some areas. I believe this is called shivering. Any suggestions as to how to avoid this? Seems to be more prevalent on lighter shades of velvets. Should I fire the underglaze before putting french dimensions on top? Could it just be that the clay was too dry when I applied the velvets? Surface of the clay too smooth (I use a rubber kidney to rub out surface imperfections) Or is it that the 2 products aren’t compatible? Thanks Link to comment Share on other sites More sharing options...
Min Posted August 24, 2020 Report Share Posted August 24, 2020 Hi JMP and welcome to the forum. If underglazes are applied too heavily they will lift off the claybody, did you use the Velvet's as they came or did you water them down? For opaque coverage it's better to do 2 or 3 watered down layers than 1 heavy coat. Also, if doing more than 1 coat make sure the previous layer is dry before putting on a second / third coat. If the underglaze is bonded well to the pot then the Duncan French Dimensions should be fine going overtop of that. Given that you had it lift the underglaze I think this also points to the underglaze not being bonded to the clay. I think it's far more common to have lifting of underglazes than shivering. I would apply the underglazes on greenware then bisque then apply the raised French Dimensions then when that has completely dried dip the pot in your clear glaze. Link to comment Share on other sites More sharing options...
JMP Posted August 24, 2020 Author Report Share Posted August 24, 2020 I use the velvets straight from the pot. I’ll do all of the things you’ve suggested! Thanks so much for your help, much appreciated. Link to comment Share on other sites More sharing options...
Min Posted August 24, 2020 Report Share Posted August 24, 2020 @JMP, it's always a good idea to try out new techniques on test pots or tiles before committing "real" pots to them. Try watering down the underglaze(s), apply 1,2 and 3 coats and see how they do. Try the dimensional glaze under and over the clear, see what happens. Link to comment Share on other sites More sharing options...
JMP Posted August 24, 2020 Author Report Share Posted August 24, 2020 Good idea. Thank you. Link to comment Share on other sites More sharing options...
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