Friday, August 9, 2013

Sprigs and Stamps

My sculptural work almost always utilizes homemade sprigs and stamps for surface decoration, but it occurred to me last week that I've never actually written a full explanation of how these tools are made. I refer to them in passing and I have made a video demonstrating the technique but never a full explanation here on the blog.

a piece with layered sprigs (yellow and green) and stamped texture (red)

A stamped effect can be achieved with most anything one can find, including sticks, pen caps, toys, toothpicks and any number of clay tools. I have boxes of such materials around the studio and am constantly collecting interesting bits of detritus to use in my studio from around the house, in the yard or  while out on a walk with my family.

stamped impressions from a mechanical pencil and a Handi-Snacks stick

Stamps can also be made out of clay. Just like any bit of material can be impressed into the wet clay to create a texture, any bit of material can be impressed into wet clay that is then fired and used as a stamp itself. Fired clay, which is technically called ceramic once it has undergone a chemical change inside the kiln, is stronger than unfired clay and can be pressed into wet or leather-hard clay over and over gain without cracking or deteriorating. 

impressing a ceramic stamp into leather-hard clay

A ceramic stamp fired to a relatively low temperature is also porous, meaning that it absorbs some of the water from the wet clay into which it is impressed. The wet clay shrinks enough to pull away from the ceramic stamp easily. A plastic stamp might stick to the wet clay, causing an imperfect transfer of the stamp's texture.

this stamp was made from repeatedly pressing the end of a pen or similar tool into pinched wet clay

Sprigs are basically small molds that can be used to shape wet clay into desired textures. I use sprigs to quickly (ok, relatively quickly, I can spend hours adding sprigs to one piece) recreate complex textures that I then layer or arrange onto my sculptural surfaces. Sometimes I fill a surface with sprigs, sometimes I alternate sprigs and impressed (stamped) textures, and sometimes I juxtapose sprigs or stamped textures with smooth surfaces or non-ceramic additions.

long sprigs made from pea pods

Clay sprigs work well for the same reasons that clay stamps work well. The wet clay retains the details of what was used to make it. I often make my sprigs by pressing clay onto organic materials including oranges and strawberries which would not hold up well over long use. 

sprig made from the end of a strawberry

The fired ceramic sprigs are strong and porous, allowing them to be used over and over again without breaking. Sometimes if I use a sprig mold for too long, I need to let it dry because it has become saturated with moisture and wet clay starts to stick to the wet ceramic.

pressing wet clay into a sprig mold

Using the sprigs is very simple. I simply press wet clay into the mold. If I were to leave the clay alone, the sprig would absorb the moisture, causing the clay to shrink and pop out of the mold. I usually score the back of the clay while it is in the mold and either pry out the wet clay or press the clay and sprig mold onto whatever I want to decorate.

using a scoring tool to remove the wet clay sprig from the ceramic sprig mold

The wet clay pressed into the mold retains much of the texture and shape of the sprig mold in reverse.

wet clay sprigs can be added onto wet or leather-hard clay 
I find that the change in material and texture, as well as color, changes viewers' associations with otherwise familiar textures. People often do not always recognize the sprigs as strawberries or oranges when they are flattened and layered in clay and glaze on my abstract sculptural forms

the completed form with sprigged decoration

Making a Sprig
Making a sprig mold is as simple as using it. This is probably why I have overflowing drawers full of sprigs all around my studio. I often choose to make sprigs from whatever natural and manufactured materials I come across, figuring it is easy to make them now and decide later, after they are fired, whether they will be useful.

wet clay ball

I start with a piece of wet clay, that I roll into a smooth ball. I usually press this ball into a small bowl using my thumbs or fingers to alter the shape. Depending what materials I am pressing the clay onto, I may need a different size or shape ball or bowl of clay.

pinching a wet clay "bowl"
I then carefully press the ball or bowl of clay onto whatever I wish to use to make the sprig. After the sprig has been fired, it will be used to create a smaller, monochromatic version of whatever it was that formed the mold.

preparing to push the wet clay bowl onto a pinecone
On something like a pinecone, both ends and the side can be used to make three different sprigs, or more. It is important to choose materials that do not have undercuts. If the clay used to make the sprig mold has to wrap around the original material, it will have to be bent back or broken to remove it.

pressing the wet clay onto the pinecone
If a form does have an undercut, sometimes I will simply pry off the wet clay from an undercut, leaving the resulting shape altered by the motion of pulling it away. Other times I will rock the mold back and forth slightly to make a wider impression than the original shape. I also rock the clay slightly to create a wider opening if the original material has very straight walls. Regardless, the clay mold must be removed from the original material or it may crack while it dries or be impossible to remove later.

peeling the clay sprig from the pinecone
It is also important to keep the rim (the exposed edge of the sprig) relatively thick so it is less likely to crack before firing or during use. This rim also creates a logical edge for excess clay to be removed during forming.

completed sprig (before firing)

After shaping, the sprigs dry pretty quickly. I usually fire them to cone 08 or 06 (though sometimes I fire them in an 04 glaze firing if that's what is in the kiln). I have made sprigs as big as 3 inches wide and as small as the end of a Sharpie pen. I rarely wash the sprigs, but they can be scrubbed clean if clay starts to stick inside them.

sprigs and the original materials used to create them

1 comment:

  1. I like using sprigs and stamps. Your info on making them was very interesting and good "how to" directions. Very clear and concise. I know what I'll be doing!


Tell me what you think about my work or this post