Intro: Cat Head - From Clay to Bronze, Lost Wax (with Patina)
I was first introduced to foundry last spring and I had the chance to discover that I can express myself with clay. I was surrounded by talented people and I will try to teach you what I have learned from this experience, by working with some of the first mediums humankind has been able to master.
I wanted to make an interesting book ends set to offer as a present. If you don't have access to a foundry you can make one yourself but that's another project alltogether. I will show you how I did it step by step and the products I used to make it so. I am most comfortable to work with clay (plasteline) rather than drying type of clay.
- Clay (sulfur free)
- Release agent
- 1" brush
- Wax (for lost wax)
- Metal (bronze, aluminum of what you have access to)
- 2k tech patina
Materials for wooden stands (optional)
- 4 9”X9”x1” pieces of wood
- Wood glue
- 8 wood screws
- 4 metal screws
- Crock pot or just a regular pot on the stove
- Small rotating tool to polish
Step 1: Pick Your Clay and Start
I prefer to work with Chavant Clay myself you have to use Sulphur free clay and this particular model that I made is with medium hardness clay. You can do any bust you feel like or any animal for that matter but I went with a low detail cat head.
Step 2: Making Sure It Doesn't Stick to the Silicon Mould
Before we cover our clay with silicon, it's safer to spray it with a release agent just to be on the safe side. This way it will prevent us from ripping the mould trying to get the clay out.
Step 3: Prepping the Sculpture and Applying the Silicon
I like to make a little wall with clay around my sculpture to prevent the silicon from running all over my workspace. I sculpt on a regular lazy susan. Always work with gloves when mixing silicon. It`s time to measure equal quantity of Part A and Part B and stir it well, cover the piece with the silicon, bring it back to the top with your brush. This step will be repeated 2 more times over the piece. It is necessary to wait 6 hours between each application but it's all worth it to have a reusable mould.
Once it is dried it is now possible to remove the clay from the mould and get some wax to start our production!
Step 4: Wax Time
I use a mini crock pot to melt my wax. The model you see there is hollow otherwise the casting will be heavy and expensive. I fill the mould, wait a few minutes and put the wax back in the crock pot. I do this 3 times or 4 times depending of the temperature of the wax. I wait 45 minutes between each layer and wait more than 4 hours before removing the wax model from the mould.
I make cones with styrofoam cups and put them in wax to make a base for the head. These base will be the entry for the metal when we will cast them.
Step 5: Prep and Slip-casting
It is now time to get the wax ready for the slip casting. We want to keep our models from falling in the slip when they will be dipped, this is why we make those trees (from the styrofoam cup we dipped previously in the wax) then we add branches to and the pieces firmly with a mix of glue and wax. On the second picture you can see the models have been dipped once in slip then in sand. This will be done for 3 consecutive days. The last picture shows the completed cast and the wax is still in it.
Step 6: This Is When the Wax Gets Lost
It's now time to break open the hardened shells, to put our models in an oven to melt the wax and let it leak out of our models. This is the reason we need one wax per model we want.
Step 7: Melting and Pouring of the Metal.
Time to melt our metal. At the foundry where I go I had access to aluminum and bronze. I made pieces of both metals. We can see the iridescence of the molten metal in the mould.
Step 8: Breaking the Mould and Cleaning the Pieces
The slip has hardened and the metal has cooled off and it's time to break the shell to revele the metal pieces. The top left one on the second picture is my cat head, made of bronze and cleaned up. It was grinded to remove the overflow of metal and it was sandblasted to give it a finer finish. The two aluminum ones were made from sand casting (but that's for another instructable).
Step 9: Patina and Final Product
I use an easy way to create the patina on the bronze. I use a solution from 2k technologies in order to easily create a patina on my pieces, it is easier than the traditional way of making patina finish, you only apply it with a brush and wait for it to dry. I blackened the bronze then buffed it with a rotating tool. This is the final look of it.
It could be screwed in a single wooden piece as well but since I wanted book ends I will add the step that I completed to do so.
The last photo are the complete book end with the head and the tail of a cat but you can do it with two similar busts or any interesting piece you can create with clay.
Mark where you can screw in the metal piece on the wood. Use the drill to make holes in the bottom plank then use the metal screws and fix the head in the plank.
Take 2 more planks, glue and clamp them so they sit at 90 degrees while you screw the bottom to the side. Make it sit on its bottom and you have book-ends. You can add feet at the bottom if you wish.