Chris Kirby is an industrial designer from Canada who has been based in Tokyo for a few years now. He’s about to make his return to Canada, but before leaving joined PechaKucha Night Vol. 59 in Tokyo last week to talk about latest projects, which revolve around the production of porcelain products using the slip casting process.
Below are the images used in his presentation — which covers the process — as well as Chris’ talking points (provided by him).
In a nutshell, the slipcasting process is:
1. You make a model of the thing you want to reproduce (the positive).
2. You make a mold from that model (the negative).
3 You use that mold to churn out a bunch of products (positives). You pour liquid porcelain into the mold which forms a porcelain clay shell on the walls of the mold.
In a much bigger and painstaking nutshell, there’s a lot more work that goes into it. Designing and producing your model, perfecting the mold design, waiting for things to dry and harden, trimming off excess clay, two different bakes, lots of sanding, applying the glaze, and boatloads of dirty dishes.
After lots of hard work, you get your final piece in all its designerly glory. I learned that perfectly reproducing the same piece over and over again was very hard. But this inspired my current work.
I was inspired by the mold-making process. I really liked the shape of the molds — since they are negative castings of the model, the shape is unexpected. I wanted to capture this in the product. I wanted the product to be the negative.
If the product was going to be the negative, the mold would have to be the positive. I decided to use plaster blocks. And then use the blocks to build the negative space of the mold.
I stacked the blocks so that they formed a cavity on the inside. At this point I’m not quite sure what the shape of that cavity is going to be.
This is another incarnation of the mold. There’s an interesting art to creating the mold — its part random, and partly dictated by the structure of the mold itself and the blocks you’ve got on hand. A bit like Tetris, there’s never a long one when you need it.
Now clamp together and pour in the liquid porcelain. The plaster of the mold absorbs water from the liquid porcelain and builds up a shell of hard clay on the walls of the cavity.
Then you pour out the excess liquid from the center, and allow the shell to dry on the walls. Then you “open” the mold by taking the blocks away. You can see where the liquid porcelain has flowed between the blocks.
As you continue to take the blocks away, you get your first glimpse of the cavity that was built. It’s a much different process than working from an initial design and an initial model.
And then can see the final form. A porcelain casting of the negative space. This is before it goes in the kiln — after the kiln it comes out white.
Because you can’t put the blocks together the same way twice, each piece is unique. Its not about being unique for uniqueness’ sake, its just more fun to make a different object or try something new each time. This makes them very exciting to produce. I still haven’t been able to stop.
You get these really fine translucent flakes coming off all sides. The first inclination was to cut them away, but they added so much that I decided to keep them. They were one of the happy accidents of the process.
Embedded in the final piece is a lot of information about how it was made. You can see where blocks were placed. See the broken corners.
When I first started making the plaster blocks they didn’t come out very well — the corners were broken off and some of the blocks broke in half. The studio I work at is paid by the hour — an environment that favours haste over perfection — so I used the broken up blocks as they were.
Typical slip casting demands perfection — the mold is precious since any flaw is transferred into each reproduction, and all surfaces are painstakingly sanded and finished. But these seem to get better with age. Broken blocks and scars on the mold pieces only add interest to the final forms. The process is evolving.
Then I had the idea to make one really thin. The longer you leave the liquid porcelain in the mold, the thicker the walls of the piece are, but if you pour the porcelain liquid out after only a minute or two in the mold, the form is thin enough that a light can shine through.
You get interesting effects in the lighting. The outside is all sharp and gnarly, but the inside surface is fluid and smooth from when the liquid porcelain was poured out. You get thick build-ups in the corners. You get light reflecting off the flakey bits.