Pulled out of the kiln the first model of the ceramic siren I made some considerations:
- the ceramic now that it’s “biscuit” is much whiter.
- the embossed lettering on the top is perfectly legible
- there are some “dirt” marks I could have removed before I put in the oven
- adjust the hole at the base because it is slightly off-centre
considerations not made but that I should have made:
- try to see if the light goes through by inserting a light source into the volume (biscuit status)
- measure the diameter at the base before and after placing it in the oven (restriction usually around 18%)
At this point you have to start with the glazing process.
I had Tas explain to me how to use the glaze room.
It’s nice that in the pottery workshop there are spaces where you do completely different things and the glaze room was the only one I was missing. Perhaps the most evocative, there are these jars with the symbol of danger on the shelves that give a sense of chemical laboratory, a special and sterilized place where you have to mix the ingredients to get crazy things.
The choice is not so wide of colors and for terracotta there are even fewer options (cooking at low temperature) but fortunately the siren is not.
I decided as first thing to make the top red but, opened the red, I found a completely dry jar and the powder as hard as stone.
Once called Tas explained to me that in order to be able to use it you had to do a very long process and so I rolled up my sleeves and started to sculpt this pigment now become rock.
It took me an hour to recreate the right composition between powder and water in the jar but I learned a few things about how to prepare a glaze. I had already done it in Brazil to experiment with pigments but once again I saw another way of working that brings other suggestions.
At this point I dipped the top part in the red container and, after checking that it had reached all the desired parts, I pulled it out.
Tas told me that I was a few seconds too long with the object immersed and, after seeing the firing, I say he was right.
Note for the next time: mark the point of arrival with a tape that buys the parts not to be submerged so that you can go safer without being too much with the object immersed in the glaze.
For the lower part I chose the only color that came close to blue or black, this turquoise with small spots, very nice but perhaps not very suitable for what I was looking for. As I decided to try this combination anyway.
Once cleaned some smudges and other small details I put the items on the shelf suitable to I waited for the weekend to see the final result.
Pretty is pretty. Things to change: a lot.
I really enjoyed seeing the first piece finished but of course there are many things that didn’t go as I had hoped:
- the glaze (too thick as Tas said) has erased the embossed writing not giving way to see any of these details (not even the crack on the side)
- light does not pass through the surface in any way
- color scheme to review. The blue is very beautiful but also very organic, while the red is full and intense.
- The base has been placed on the sand to avoid it sticking to the plate (positive) but you can feel the grains all around.
So I decided to try to redo the model with the care taken in the first part.
If in the first prototype the time in which I left the ceramic inside was 30 minutes and it turned out too often, in the second one I wanted to try to halve the time and bring it to 18 minutes.
Let’s see what the thickness will be like and if this will allow the light to pass through it.
Here some dimensions to compare the original siren to the one at biscuit status and the glzed one:
Original model size:
– Diameter: 16 cm
1st time: 30 minutes waiting and 2 hours to dry.
After glaze dimensions:
– Base diameter:14,2 cm
-Diameter of the hole: 7.5 cm (not regular)
2nd time: 18 minutes waiting and 3 hours to dry.
Before glaze dimensions (biscuit):
– Base diameter: 15,5 cm
– Diameter hole: 8.5 cm (not regular)