Experimenting With a Lego Compatible Polymer Clay Figure

I made this polymer custom clay figure as a gift in the first Instructables Gift Exchange. As the person portrayed uses Lego as educational means in a professional capacity, I added to the following things:
- A gear like chest emblem.
- Some Lego-compatibility (meaning Lego studs will fit).
- A kit for making steam boats, as used in my own workshops for children.

I used a simple copper wire bendable armature. This is a very simple way to make a figure with some degree of posability. It is not suitable for playing, but it is for displaying and changing the pose once in a while.

Step 1: Materials

Polymer clay of your choice (I used Sculpey III this time)

Copper wire (I used 7 strands from a 16 mm2 mains installation cable, they are about 1 mm diameter each)

Brass bushings (I used bushings with a 5 mm outside diameter, 4 mm diameter inside)

Some Lego parts

The steam boat materials as described in:
https://www.instructables.com/id/Pop-pop-or-put-put-steamboat-made-easy-for-childre/

Step 2: The Bendable Armature

I started out making the wire armature as shown. Were the polymer clay parts would come put a fitting length of brass bushings. This way, when bending the limbs, the forces ar not concentrated on the polymer clay part edges which could not withstand them.

The seven strands allow to make five fingers and leave two strands to be bent to make the palm of each hand.

Step 3: First Sculpting and Baking Step

The brands of polymer clay I know all warn for over-baking, but with intermediate cooling, I never had any trouble. Baking some of the parts several times gives a lot more sculpting freedom (no sagging).

I first made the base colour part for the breast emblem and the head. At the same time I made the Lego-compatible feet.

I did not sculpt the head on its bushing, but drilled a fitting hole later.

For the feet I experimented with baking them, while being on a Lego part. That did work a 10% as the Lego parts warped (not surprisingly). However, one foot was usable. The other tore as part of it remained stuck on the Lego part. I was able to salvage it with some retouching in the next baking step. A releasing agent would have helped, but removing the part before baking is still very delicate. Applying a release agent and keeping the Lego part on (to be sacrificed) is not an elegant solution either. In the last step you will see a much simpler solution.

Step 4: Second Sculpting and Baking Step

The body parts are sculpted on the bushings and the feet are added (I only took a photo when finished, because I needed clean hands to hold the camera).

The breast emplem is carefully pressed into the trunk part. The letters carved in the breast emblem are filled with black clay, not bothering with obtaining a clean result. This will be achieved by wet sanding after baking.

The eyes and hair are added to the head.

Step 5: Finishing

After the second and last baking step some sanding is done. Sculpey advises to sand under running water. I guess that is not only to obtain a good result, but also to keep the sanding dust from being inhaled or ingested. When needed I start with coarse grained wet sandpaper (e.g. 100 grit) and I finish with 320 grit. To my experience, going any finer does not give much improvement. I finish by rubbing on a coat of furniture wax, giving a nice semi-gloss. It’s easier than varnish and more resistant to bending.

Finally I wanted to ad more possibilities to connect to Lego. Gluing on Lego parts is of course one way. But a simple 5 mm hole in baked polymer clay works quite well, without sacrificing any valuable Lego parts. The dimensions of the hole and the stiffness of the polymer clay gives a reasonably good hold on a Lego stud. Of course, if you want to hold on to more than one stud, you will need to position the holes very accurately one to another (making a template should be a good way to do it).