Updated: Jan 17
Thinking about glaring my ceramic objects - I want to keep it a natural colour, similar to the stonewares beige/brown, but give the ceramic more of a sheen or satin finish so it resembles a similar finish to the weaved wheat of the corn dolly.
Went through multiple glaze books to find an appropriate recipe, these are the ones I liked best and decided to test (from Emmanuel Cooper's The potter's book of glaze recipes):
The majority of the glazes I chose were domestic, meaning they're food safe and can be used in the home/kitchen. But I also tested one that wasn't - interesting again to explore domestic functional wear but make it unusable, but in a non visible way.
In tutorial with Bridget she suggested I look into liquid hard waxes and Osmo oils as an alternative to glazing. This would give the ceramic a shine without firing a glaze onto the body. After research into them both, the most suitable to my stoneware clay would be the Osmo Polyx-oil original - its designed for wood but can work with porous materials, therefore i would have to apply it to my bisque fired pieces and not have a final firing. However, I want my pieces to be functional (even if they're not used), so will stick to using a glaze and final firing.
Trialled glaze recipes:
Process photos of working in the glaze room:
To make a glaze:
1. Weigh out ingredients using scales accurate to 0.1g.
2. Add enough water to just cover and let sit for a couple minutes
3. Mix together and pour through a 120 mesh sieve into another pot to get rid of lumps
4. Sieve for a second time to ensure the glaze is fully mixed together
5. Apply to bisque fired ceramic
HEALTH AND SAFETY:
Glaze ingredients are extremely toxic so it is important to wear a suitable vented mask (not just fabric one) to ensure no harmful chemicals are breathed in. This is vital when handling dry ingredients or using the glaze spray booth.
Furthermore, glazes are also toxic to the environment so avoid making too much that results in waste. Pour excess glaze into a container for use another time.
Finished glaze tests before firing:
Glaze tests post firing at 1220º:
These glazes are nice and I managed to achieve the satin finish I wanted with glaze 28, however I was unable to make the colour I wanted. I aimed to create a light brown/honey colour, similar to wheat that the corn dolly is made from. These colours (except 31) are much lighter than intended, so I want to do some more tests.
I added transparent glaze to the inside of this vessel so the raw colour of the clay can be seen. For the exterior glaze, I made up a glaze starting with the stoneware transparent as a base (700ml), with an addition on 1.6g red iron oxide sieved in with another 1.4 just stirred in, as well as 0.5g yellow iron oxide also just stirred in. I added this into the spray gun and applied about 4 layers over the exterior of the vessel.
It will be interesting to see how this turns out, although I only used a very small percentage of oxides as colouring, they're very strong in pigmentation so I'm excited to see the result. Also, when transparent glaze is applied thinly (which the spray gun allows), it doesn't have a fully glossy finish. 4 layers should be thick enough to show me the full colour pigmentation of the glaze, but also thin enough to be slightly glossy but not too shiny.
I had initially thought about also leaving this piece unglazed but after my test tile (far left image of tests above) I don't like how pale this clay is. This was fired to 1220º, so I want to do another test at a higher firing temperature of 1260º to see if this makes it darker at all. Alternatively, if I also don't like that, I want to apply a satin glaze with a speckled light brown colour. Over the next week I will continue my glaze research to find recipes to achieve this. Im really happy with the finish of my no.28 test tile, so could experiment with adding oxides or pigments to this as a base recipe.