Neptune is my 6th large metalclay sculpture (8″x9″) based on an open 3-line, minimalist framework. By that I mean that the entire structure is built around 3 carved coils (lines) of metal. Previous sculptures have taken as many as 20 firings to deal with uneven shrinkage, uneven sintering, bad batches of clay (yes this does happen and I can prove it), etc. I am now able to fire in 5–8 firings and with more reliable outcomes.
I have learned a lot along the way, including changing my brand of clay to ones that use stronger binders that are more suitable for sculpture. This technique requires a lot of “engineering” to get these relatively fragile structures out of the kiln. While my technique may not be for everybody, I have tried to lay out a few of my Tips & Tricks that you may find useful in your own work.
My drawings are focused on finding the movement of the creature in a 3-line frame. I try to figure out what is the minimum number of lines necessary to create movement. That is my frame; my “bridge” structure. It will carry all the weight of my piece, including the weight of the metal clay in the kiln as the binder burns off while the metal is sintering.
Build a working Model/Frame
Tips & Tricks: Build an accurate drying form out of firm air-dry clay. This insures that your pieces will fit together at the end with minimal fussing. Here I use a German clay that dries rock-hard and absorbs moisture from the metal clay. I then carve grooves to hold the shape of the metal clay as it dries and shrinks. It is useful to oil the surface to avoid sticking.
Roll the basic coils that form the structure of the piece, similar to the framework of a bridge. They should be evenly sized and laid to rest on the drying form to dry in the desired shape.
Carve and Assemble
This is where the real work begins. Each segment of the frame is carefully carved and fit into a 3-dimensional shape that is self-supporting when subjected to heat and gravity in the kiln. It takes a bit of engineering and lots and trial and error to get this to happen. My early sculptures took as many as 20 firings to repair breaks.
When working with large pieces of 2 different clays with different shrinkage characteristics, I fire them separately, then attach them later with clay-paste at a lower firing temperate.
Here is the steel tail being formed over a removable form.
Tips & Tricks
Here I am using water-soluable packing pellets formed over armature wire. I use a very small amount of water on my fingers to press and shape them over a curved wire. I drape my 8-card thick clay over the form in the shape of the curved form. The packing pellets absorb the water from the metal clay as it dries, leaving a nice hollow form. The pellets themselves disappear. If you use a soft wire core, you can easily pull it out.
Head, Legs, Tail and ribs are added in separate, additive firings (total of 10) until the final sculpture is formed. Then the final piece is torch patinaed.
Gemstones and Roman glass details are added before final mounting on stand. I use a good, clear epoxy to add these details to a sculpture. There is no need to fire them in place.