Printing Pots by Joan & Jack Hardie
In July 2014 we went to a workshop on 3D printing to find out if it might be possible to make things in clay. The answer was that it should be, and we were full of enthusiasm for the design possibilities it might give us. Now we design and produce pots that could not be made in any other way. Here’s how it works:
- The 3D printer is like a robotic coiling machine. Soft clay is extruded out of a plastic syringe and through a fine nozzle by a motor-driven piston. The position of the nozzle is controlled by three other motors, which move according to the instructions for the design.
- The design of the pot has to be worked out beforehand, using our knowledge of clay to make viable designs. We use the Rhino 3d Computer Aided Design program to get the idea onto the computer screen. Another program slices the design into layers and then creates G-code – thousands of instructions to move the print head one tiny step at a time in a continuous spiral.
- As we are using very soft clay we put three small fans round the pot to discourage it from collapsing. The resulting pots have uniform thin walls and show the fine layers. Printing the pot takes up to an hour for the largest pots we can make (currently about 25cm high).
- This probably all sounds rather clinical to hands-on potters but I find the design process surprisingly similar to when I’m hand-building. New possibilities suggest themselves all the time, and I end up making several related designs at a time. And of course firing and decoration are as important as normal.
- Preparing the clay is very hands-on! We need the clay to be softer than anything you could work with by hand but much stiffer than slip. Basically, it’s very sticky indeed. We add water and a bit of deflocculant to bag clay, mix it in a kitchen dough mixer, and then don disposable gloves to wedge it on a wet plaster bat. Even tiny air bubbles or variations in consistency distort the pot when it is printed
There was a lot of learning involved in all this! As a first step, Jack built the printer using a design by Jonathan Keep and a lot of heroic Googling to source all the parts. Meanwhile, I experimented with sticky clay and compressed to find a suitable clay mix, making many interesting wiggly pots in the process. We both learned how to use Rhino to design pots, and over several months we gradually refined all the variables to get consistent quality in larger pots. ( Rhino 3D Computer Aided Design program to get the idea onto the computer screen. This stage is very precise as Rhino works to one hundredth of a millimeter. The photo shows the four different views of a shell vase design in Rhino.)
It’s been interesting and fun. (The design of a printed pot has to be worked out beforehand in every detail as the printer will do exactly as instructed. We have to use our knowledge of how clay behaves to make viable designs)
If you want to know more, we have a website www.printedpots.co.uk with more about the printer and a gallery of pieces, and a facebook page with a few videos (search for printedpots)
My thanks to Joan and Jack Hardie for sharing this interesting development – personally I was really impressed at the amount of research and development they had to undertake to get this working – fascinating article – Editor