|Monthly Tech-Tip |
All the YouTube videos I watched focussed on techniques of applying the lines and glazes. But what is the black-line recipe? Does it require gummed glazes? For this version 1.0 black-liner, I mixed enough wax emulsion to make it easy-to-apply using these needle-tipped applicators (80 mesh sieving was needed to make it flow well through the nozzles). At cone 04 the lines are bleeding excessively. This recipe is 50:50 Ferro Frit 3195 and Mason 6666 black stain (plus 2% Veegum to harden it and slow down the drying). Version 2 will need to reduce the frit or expense it with a filler, perhaps feldspar. Another issue was my colored fill-glazes, they have enough clay to suspend and harden them for normal use, however during application here the bisque pulls water out of them and they dry too fast. For future versions I will add VeeGum to slow the drying (I suspect CMC Gum additions would not resist well from the lines). Another issue: Even using pure wax emulsion, the lines are not resisting the glaze as well as I expected. Further testing will demonstrate if this can be improved by glazing sooner after line application (I waited a day for this test). Or will I need to use an oil base instead?
Cuerda seca is getting much more popular. These are for the lines and fill in. From Amazon. Various needle gauges are provided. It is clear to see why the resist slurry needs to be sieved and free of particles (they will clog the needles).
A method of decorating terra cotta clay tiles by flood-filling liquid glaze into areas delineated by colored wax or grease lines.