Finishing and Detailing a Sculpey (Polymer Clay) Sculpture

Sculpey is a great medium to sculpt with, especially for smaller sculptures that require a lot of detail and/or need an armature to support extremities or to create movement in a piece. Here I will go through the steps I use for the final details of a sculpture and the tools I use to do so.

This sculpture is made with Super Sculpey, which is a polymer clay that can be cured in the oven by baking at 275° F. There are a few varieties of Sculpey- the "regular" kind, (which is white) the beige "Super" Sculpey which is slightly harder in feel and can get more detail. There is also a grey "Firm" Sculpey which is quite hard.

The sculpture has an aluminum wire armature, and the bulk of the horse's body is made with layers of aluminum foil. This keeps both the weight of the piece down and it makes the Sculpey thin enough to cure evenly in a shorter amount of time. Be sure to pack the aluminum foil firmly to avoid air pockets.

So, now to get into the details...

Here are a few of my favorite tools. Mouse over photos to see details. Most of these tools are Kemper brand (http://kempertools.com/). The smaller wire rakes are from Valdez tools, bought at Kit Kraft (http://www.kitkraft.biz). The metal dental tools can be found at craft stores and online, some similar ones can be found from the Compleat Sculptor (http://www.sculpt.com/catalog_98/steeltools/Stainl...)

And of course, a good ol' X-Acto knife.

When starting a sculpture, it is important to plan ahead so that you can build a sturdy base for your piece. Here I have sketched my idea, and used the sketch to assemble the armature. This horse is going to be mounted to its frame from the back, so it only is sculpted from one side, and the armature is basically flat on the back, for a direct connection to the frame/wood shadow box it will eventually be attached to. I used a small block of wood (1/2" plywood) as the main support for the bulk of the sculpture, which will be hidden in the chest of the horse. I then attached aluminum armature wire (1/8" diameter) with screws and washers (wrapping the wire around the base of the screw, sandwiched in with the washer) and in a couple spots I reinforced the shape of the wire with staples. The wire for the neck was twisted together to add strength, as horses' necks are quite large.

Note: It is important to keep your proportions correct when building an armature. Using the head of the subject as your unit of measurement, measure repeatedly using calipers (shown in the upper right of the photo) to make sure you have built the armature with the correct proportions. There are many resources online and in art books to determine these proportions. The standard 7 1/2 head system works well for human forms. I admit here that my horse ended up being a little short in body length, but overall I tried to keep it realistic. For me, this armature is unique- usually my armatures for human figures are much simpler and have no wood or extra parts, just aluminum wire.

Note #2: Be cautious when using wood in your Super Sculpey figures- I used a relatively small piece here, as a large piece runs the risk of being unpredictable in the temperatures required to cure the clay (275° F). If you are determined to use a larger piece of wood, you can pre-bake the wood to test if it expands or cracks. I have also had wood leach sap if it is fresh! Smoky oven parties are no fun!

To attach this figure to its shadow box frame, I used 6/32 machine screws (which were threaded through both the wood block and the wires of the hindquarters) with nuts and washers in the back of the frame.

After you have a sturdy armature built, use Aluminum Foil to bulk out your sculpture and get the rough shape of the figure started. This is a great material for this because it is inexpensive, lightweight, and won't be altered by the heat of the oven. I use regular old aluminum foil from the grocery store, I tear off sheets and fold them a few times into a strip about 1.5" to 2" across and wrap it around the armature. I pack the foil as tightly as I can, so that it doesn't move or depress when I start putting clay on. You can even smash the foil down with a hammer or other sturdy tool if it won't stay put. I take thinner strips of foil and wrap them tightly around armature wire of the limbs, or if the limb will be very thin, you can also wrap finer wire (I use 24 gauge floral wire) around the base wire. This helps the clay grip to the wire.

After you have a good base built up with the foil, it's time to start adding your clay! I like to warm up the clay a bit with my hands, smashing it around in my fingers. Super Sculpey comes in bricks, one pound each, and these bricks are made up of strips. I only ever use one strip (or less) at a time, otherwise the clay can be hard to maneuver- it's easier to make sure it is really blended together if you use smaller pieces. In the photo, you can see I have roughly sketched in the major muscular forms of the horse. These will get refined using the next steps.

Here I have rounded out, smoothed, and baked the main forms of the body. I usually bake the sculpture at least twice- first I sculpt the head and torso, bake, and then add the legs/arms/hands (when sculpting a human figure). This allows for more delicate detail on the smaller parts of the body. Also, it allows you to make small changes to the more expressive parts of the figure (hands especially, or in this case, hooves) after the larger parts are locked down. This way, the limbs can be moved out of the way while sculpting the body. Also I find I often mark up or ding the extremities with my tools, so by breaking it up into two steps, it's easier to keep track of smoothing out any imperfections. Baking the torso first gives you a hard base to build up the detail onto. Sculpey is great for this- you can blend uncured clay onto baked clay and it will bond well once baked again.

In this step, I am forming the major muscle shapes with my fingers. I try to make sure that the clay is well blended, with no air pockets. If you get an air pocket, you can puncture it with a knife or tool, and smooth it out.

One of the first tools I use when defining the muscles is this wider spoon-like tool. It is great for blending pieces of clay together, and can be used to compress spots.

Note: I am constantly switching back and forth between tools, so these "Steps" are really in a very basic order- I will often go back to step one, then 4, drawing, then use my rake tool, re-drawing, then back to scoops, etc. It is a mix-and-match process of whittling down detail to a finished form.

This step is more of a constant technique- drawing the separations between muscles, drawing where body markers (on a human, this would be things like the navel, pelvic bone, suprasternal notch, etc) are, and drawing just to remind yourself of the directions or gesture of the sculpture. It is important to continue to draw on your figure so these details and major markers do not get lost. I use a pointed dental tool or an X-Acto knife to draw on my pieces.

Details get finer and finer as the sculpture gets more finished. Here are two examples of how I use smaller tools to scoop out and compress different parts of the figure. Horses have a great deal of beautiful information in their feet and legs- muscles, tendons, etc- and you need appropriately sized tools to get the amount of detail needed.

The rake tool is very important for getting forms to become rounded and smooth. You want to have a variety of sizes of rake, and always start with the largest and work down to the finer ones. The rake cuts the imperfections down in your sculpture. Use it like you crosshatch in a drawing- alternate directions across the form, so that you aren't just going up and down a shape, but over across it, so it rounds out more overall. You want to use a light touch with a rake, as it can gouge into your clay and leave deep marks. You want to use many light marks over and over to create the changes you want, not deep marks you can't go back from.

Note: This is a tool I made myself using brass stock, a hacksaw blade, and a propane torch (to bend the saw blade) - then sand down the blade points so they are almost flat. Here is a good tutorial on how to do so, fairly similar but a bit more complicated than how I've made them, they also make them using piano wire:

http://www.learnprostheticmakeup.com/Make_your_own_sculpting_loop_tools_revised_sept09.pdf

Here I am using a smaller rake tool to refine and even out the forms of the horse's legs. Remember to crosshatch across the form. You want it to be a round shape- muscles are bundles of threads, not square or flat shapes.

Note: Notice the little pilly bits of clay formed with the rake? This is because this rake needs to be sanded a bit more- the points of the blades are too sharp, rather than flattened, and so it pulls up and deposits little bits of clay. This can be avoided by sanding the tool more! The blade should look like _|¯|_|¯|_|¯|_|¯|_ not _/\_/\_/\_/\_ !

Now that you're satisfied with the shapes you've sculpted, it's time to clean up all those little marks and smooth everything out. There are a variety of solvents you can use for this purpose- I started out using lighter fluid, you can also use acetone or 91% isopropyl alcohol. All of these, as you may notice, are rather unpleasant to use on a regular basis, not to mention can be fairly toxic and you should wear gloves when using them. So, while looking for alternatives, somewhere in the vast expanse of the internet I came upon a suggestion to use baby oil on your Super Sculpey, and it works rather well. And, since it's intended to be used on babies, I feel much happier handling it.

I pour a very small amount of baby oil (just a few drops) into a small plastic cup and dip a sturdy old brush (this particular one I've cut the bristles down to a flat, wide edge) in and, in a similar crosshatching manner to the rake tools, smooth out the marks your forms. Use the baby oil sparingly - if you get too heavy-handed with it, it can effectively wipe out all the detail work you've done. It works by softening the clay (you can also add a drop or two to hard clay to soften it intentionally) but if there gets to be too much in the clay or on the surface, it can become a mucky, sticky mess. Err on the side of less, and depend more on the brush strokes to even things out. I also like to tap my fingers over the surface at the very end, also in an overlapping pattern, to blend out the brush strokes.

Here are some shots of the final (unpainted) product- and the leg detail just before it's given one more pass with the brush and baby oil.

Note: With this sculpture, I knew I was going to cover the form with flocking, so, not pictured, is one more step I usually do with my human/non-furry sculptures. After the final baking cure, I sand the piece with fine sandpaper (start with 120 grit, move up gradually to 300 or 400) and then (wear gloves!) I take a small scrap of cotton rag dipped in Acetone (100% Acetone- don't use nail polish remover, it won't really do much) and gently rub out any last imperfections. I use the Acetone very sparingly, but it takes out the finest scratches and makes the piece very smooth. Best to be done outside or in a well-ventilated area! It's nasty stuff! :)

The final piece, as shown in the last photo, will be for sale at La Luz de Jesus Gallery in Los Angeles in May. You learn more about it here:

http://laluzdejesus.com/jessica-dalva-annie-murphy...

and contact the gallery director at info@laluzdejesus.com

Thanks for reading, and happy sculpting!