Ceramic Vessels: From Computer Generated Forms to Ceramic Decals

This instructable will be on several process in creating ceramic forms that are initial made in Rino and finished with printed ceramic decals. The topics covered will be: modeling ceramic forms in Rino, milling forms in foam to the create moulds, creating plaster moulds, slipcasting/press moulding, firing, and ceramic decals. This guide will give a general overview of each step, I suggest further exploration into each specific topic. I will post links and resources that I used for further expansion on the process.

There are many ways to create forms in Rino that will be able to become functional objects. It is important to think about the same ideas when related to form, as one does when making an object on the wheel or handbuilding. I think about profile, curves, and volume when creating my forms.

For vessel 1, I started out with creating a profile line for the form. From this it was a simple matter of using the "Revolve" command to create a 360 degree profile of the line. After this the last step is to "cap" the form so you can create a mould from the closed surface.

For vessel 2, I used polygons to create the forms. I took several polygons and layered them then "lofted" the sides. This created the polysurface vessel form that I wanted. I then used the "cap" command to seal the form.

From here I constructed planes for each vessel. These act as the place that the object will be milled out on. Each plane needs to have matching keys and have at least a 1.5 inch distance around the object for slipcasting.

It is important when milling out objects from rino to have a detailed guide or instrutor to help with all of the finite details. For milling out my vessels I used installation foam, gorilla glue, and plywood. I created planes specific to my model dementions, then glued two layers of foam to the board. After these dried for 24 hours I was able to put my file into the mill and create my forms. This happened in two stages, roughing and finishing. Once the forms were milled out I was then able to move into mould making.

Making plaster moulds is a very tedious and presise step. For this I highly suggest reading Andy Martins book "The Essential Guide to Mould Making & Slip Casting". Below is a general outline, used in our studio, for making plaster moulds:
1. Prepare plaster mixing materials:
   a. Clean all surfaces
   b. Gather plaster, water, mould soap, cottle boards, clay, Vaseline and scrapers.
2. Build walls around object for moulding using cottle boards.
3. Seal ALL areas with clay on the inside and outside of the mould surface
4. Mould soap all surfaces coming into contact with the plaster thoroughly and use Vaseline on the cottle boards
5. Calculate the amount of plaster and water needed
6. Follow Andy Martin's chart for adding/mixing/poring plaster
7. Allow mould to dry then remove cottle boards and clean up/scrape the mould
8. Let mould dry for between 2-5 days

Once the moulds are dry you can begin to slipcast/press mould. Slip casting is a very precise process that is also thoroughly explained in Andy Martin's book. Press moulding is much simpler.

Slip Casting:
1. Use straps to secure your mould tightly together
2. Pour casting slip into mould and allow to sit to build up wall thickness
3. Pour out remaining slip then let the cast piece sit in the mould for at least 15 minutes
4. Remove straps and carefully take apart mould and release cast piece

Press Moulding:
1. Press wedged clay into the the mould either as a slab or as coils
2. Use rubber rib to smooth out surface of the clay and achieve uniformity
3. Let clay set up for at least 15 minutes then release from the mould
4. From here slip and score the edges to attach to the other moulded piece (two half's)

Ceramic objects generally require at least two firings to become functional objects. The first firing is a bisque firing. This is done to a lower temperature, usually cone 01. Once the piece is bisqued it gets glaze applied to it then enters a glaze firing. For this we usually fire to cone 6. It is very important to pick your firing temperatures based on your clay and glaze material. It is also imperative to fire with someone who has had experience with various firings and types of kilns.

The last step in this process is applying a firing ceramic decals. I had the opportunity to attend a demo by artist Andy Brayman who offered great insight to this process.

Decal Aplication:
1. Decide where the decal will be place. Be aware that decals do not do well over compound surfaces, so flat planes or small sections are best.
2. Cut out decal carefully from the sheat
3. Place decal in shallow bowl of water to remove the paper backing
4. Carefully remove decal from backing and place on the ceramic surface
5. Squeegee the excess water and air from the decal using a RED Mudtool rib

Decal Firing:
1. Use manual kiln
2. Place objects into the middle of the kiln with a cone pack (Cone 017) in clear visibility of a peep hole
3. Place soft brick under the lid to prop it open
4. Turn up all knobs to "low"
5. After 1 hour turn all knobs up to "medium"
6. After 1 hour turn all knobs up to "high"
7. Wait until you see color in the kiln then remove the soft brick
8. At this point wait at the kiln until you see the first cone in the cone pack (cone 018) drop.
9. Once the cone drops turn off all the knobs and allow the kiln to cool

-http://lcamtuf.coredump.cx/gcnc/
-http://www.amazon.com/Essential-Guide-Making-Casting-Ceramics/dp/1600590772
-http://www.amazon.com/Ceramic-Process-Manual-Source-Inspiration/dp/0812239326