I have quite a few carved pieces that have micro surface holes but which are otherwise good shapes with parallel tops /bases and threading holes which are sufficiently large to accommodate my chosen pipes. They are far too good to waste and I only need so many 'tests' so how do I rescue them? Slip, officially not allowed on bisqued ware but described on previous blog, or engobe? Lets start with the engobe. Well, when re bisqued it's cream not white, which is a disappointment, but it may fire white at full stoneware temperatures. It was more difficult to apply than the slip when I was aiming to fill all the micro holes, so I thinned it, then thinned again. When I thought I had filled the holes with the (admittedly thicker) engobe some reappeared on firing. The engobe also remained chalky and powdery, likely to be a problem with glazing, but if I fire above 1200 C will it hold the glaze? PS I fired to 1080 C in case that was enough. The surface was no longer chalky but it was crazed. Not looking promising. This one had been taken straight to stoneware glaze temperatures. Engobe (as found in the UCLan department) has been tested and found wanting. Time to abandon it. What about decorating slip? I have tried it on a bisqued piece and refired. White, and no sign of flaking seen so far, maybe because of the flint content acting as a flux There were some remaining micro holes so I will try again with thinner slip. This is glaze UCLan 4/ 23; my final base glaze with yellow ochre added and fired to 1260 in oxidation. The piece had been slipped post bisque, refired then one thin layer of glaze then two thicker ones brushed on. The piece has problems with cracks but the actual surface is much better so slip, on greenware of if necessary on bisque seems to be the solution' Even if some holes remain, putting a thin layer of glaze on first before two of standard thickness seems to be helpful.
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AuthorI am indulging my passion for ceramics by undertaking studies for an MA at UCLAN Archives
August 2021
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