Developing new surface treatments for terra sigillata on ceramics. I’ve been fascinated with terra sig ever since I first heard of it, and have played around with using it ever since I first started working in ceramics. . I posted before that I wished the surface of my terra sig work was more saturated in color. This isn’t just an issue with terra sig, it’s also an issue with mixing in stains into clay and underglazes. The typical fix to this is to apply a glaze. That works for colored clays and underglazes, but the glaze completely burns out the unique watercolor like quality of terra sig, not to mention the smooth surface texture. . I know people have used borax and soda ash washes to “activate” the surface of clay more, and I played around with that, but I wanted something better, and I believe I’ve found it; and it works well at lower firing temperature too. . In researching the possible ways the borax and soda mix interacts with the clay surface, the common wisdom is that they’re fluxes that will make the surface clay vitrify at a lower temperature. But I suspected that a part of what was might be happening is that the boron was acting as a glass former. So, I wondered if using phosphorus, which can also be a glass former, especially at lower temperatures, might work better. . I can’t prove for sure this thesis is what is happening here, but it gets me the surface results that I’m looking for. These are tests of washes made from Tri-Sodium Phosphate (TSP) and TSP mixed with borax. It’s more than just ceramic, but I wouldn’t call it a glaze. It’s kind of a polish. . #ceramics #terrasigillata #glazechemistry #lowfireceramics https://www.instagram.com/p/CdrivGhjRFl/?igshid=NGJjMDIxMWI=
