For my wedding, I wanted to make small gifts for the out of town guests, a small thank you for the many miles they traveled to be a part of our day. Our wedding location is known for salmon – my inspiration. I found a chocolate fish at a local chocolate factory and developed a method to reproduce that shape in clay. I made fishy ornaments for each of the guests to remember our wedding.
My first attempt at molding the fish didn’t exactly go as I had hoped. Ceramic plaster (and really any plaster) has thermal reaction while curing. This melted the chocolate fish.
Of the five fish I had purchased, only three molds came out, though none usable. In at least one, the chocolate actually boiled to the surface of the wet plaster.
So I changed tactics. A woman in my ceramics class is married to a dentist and got me a bag of dental alginate, which is used to make molds of teeth and gums. Alginate does not heat as it cures and you have to work very, very quickly. It sets in less than 4 minutes.
I froze the fish just to be sure and then sealed around them with Vaseline so that there would be no undercuts in the mold.
Some of the molds came out prettier than others. Because the alginate doesn’t heat, I was able to use the same chocolate fish multiple times. (Which meant more for me to eat later! Yum!)
These molds came out much cleaner than starting with plaster. There were still air pockets, but I believe that could have been mitigated with a slower curing alginate.
After a few days, I poured ceramic plaster into the alginate molds to make a positive mold. This fish broke when I tried to remove it from the alginate.
Here are five good positive fish molds. The great thing about the alginate is that it is flexible, so it bends away from the plaster, making removing of the fishes very easy. After I pulled each fish from the mold I used rasps, metal ribbon tools, and sand paper to clean up the edges.
For the next step, I made a mold of my newly created plaster fish. I made a clay slab and built up walls around the outside edge. I then gently pushed the plaster fish into the clay slab and sealed the edges to prevent plaster from getting where I didn’t want it to go.
Then I coated the plaster with mold soap to aid in the release of the fish from the mold I was about to pour. Ceramic supply stores carry mold soap, but I have also used dish soap in a pinch. I brushed on 3 thin coats, allowing each coat to dry fully before adding another.
I was then able to pour the ceramic plaster into my clay dish. After the plaster hardened I pulled the clay away, removed the plaster fish, and washed my new five-fish mold. The mold itself had to sit out for almost two weeks in a sunny window to finally cure and dry out.
Once that was complete and the mold felt warm and dry to the touch I pressed terra cotta clay into each fish mold. I would leave the mold uncovered and come back after a hour or two to pop the clay fish out of the mold.
I removed the clay fish from the mold, then laid them out and let them dry to about leather hard. Then I used a rasp to clean up the backs and a metal round ribbon tool to take care of the sides. I smoothed all of the edges with a sponge and warm water.
Once I cleaned the fish, I twisted stainless steel wire into loops and pressed one to the back of each fish. I then covered the twisted wire with additional steel. (Note: When firing metal with ceramic pieces, it MUST be stainless steel and LOW fired.)
I used Amaco LUG underglazes, Blue-Green, Lilac, and Rose to color the fish. I did single, fluid strokes. This can be done in the greenware or bisqueware stages. I used the Amaco LUG black and a stiff plain tooth brush to create the spatter pattern.
The final glaze color for the fishy ornaments was Gare Szechuan Green.
Browse through more pottery and ceramic projects and inspiration on Create Whimsy.