Saturday, 20 October 2012

B & S armature construction- part 1

Building the ball and socket (commonly shortened to 'B & S') armature for my Gollum puppet is certainly a tricky process, and that is just the planning! When creating a detailed latex build-up puppet, making its ‘skin’ from an initial sculpt, everything must be created to the same exacting scale. The skin must be the correct size to fit the model, build upon the armature. The sculpt and the armature must be created independently, and so for everything to work, consistency is critical.

The issue I have at the moment is not knowing the size my armature will ultimately be. As aforementioned, Gollum has very thin limbs, and whatever joints I do create must fit comfortably within his scrawny frame. Without a completed joint to plan his size upon, I may end up sculpting a model that is too small, or even too big, for the skin to work later on. Since I am making my own ball and socket armature, I am somewhat restricted to the components I am both able to obtain and afford.

My plan is to gather general components necessary for the construction of my armature, and to build a test ball and socket joint (without rods). I plan on creating an armature with a series of identical joints, so this initial piece will act as a scale indicator. I will need to account for its length, width and depth in my eventual sculpt.

I will create a scale, ’T’ position drawing of Gollum, allowing me to gauge the rod lengths of the armature. Whilst the joints themselves are a set size, the rods which connect them vary in length, depending on the size of the puppet. To accommodate the joints, I will simply need to enlarge or shrink the image until they fit within his body. I can then measure the image exactly to determine the rod lengths, and thus the size my completed armature will be. With the size for Gollum finalised, I can create both armature and sculpt to match the size of the drawing. For accuracy, I will base my scale Gollum drawing on image references of him from different angles, ensuring he is the correct proportions all round.

Collecting parts

I have begun to collect the standard parts needed for my armature, basing my requirements on those specified in Sven’s tutorial, which I shall be following. I begun by making a list of materials and tools, and proceeded to purchase some items from a local engineer’s merchant.

Some items were slightly modified from the list however. After judging the size of the 8mm brass beads, I concluded a Gollum to fit them would be rather big. As a result, I scaled down to 6mm brass beads, purchased online. With smaller beads, naturally smaller rod (2mm, to fit the central hole) will be required.

Secondly, after seeing the size of the cap screws, the heads of which will protrude from the side of my joints, I decided that having nuts the other side to secure the screws would make the overall joints too wide. Looking to conserve space, following a suggestion from my dad, I shall make one side of the ‘sandwich plates’ from thicker brass strips, such that the hole that side can be tapped, with the cap screw securing directly into the plate. This should reduce the width of my joints, and allow Gollum to be smaller.

Above left: My M3 tap, to create the tapped hole in the thicker sandwich plate, for the cap screws to secure into.

Above right: My screw tie-down mechanisms- 2.5” machine screws, with wing nuts to tighten them, and two brass hex nuts for the armature’s feet rigging points.

On my second outing to collect parts for my armature, I unfortunately was unable to purchase the brass strips and rods I need. I shall need to buy these online too, it seems, as the local hobby shops seem only to have small selections. Nevertheless, I was still able to get a myriad of components and tools.

First of all, I managed to acquire two different densities of urethane cushion foam to pad out the body of my Gollum puppet. The different colours will be helpful in knowing which is which. Next, I bought a butane blowtorch, rosin core solder and flux, for soldering the metal parts of my armature together. I also bought a glue gun, which will help a lot with model making in general.

Since I do not yet have my brass parts, I cannot begin to make joints at this point. I can plan everything however to ensure that things go as smoothly as possible when I can. Following a great idea from my dad, we began to create a wooden channel to guide the brass strips when they are drilled. The drill rotating will want to spin the strips around, so placing them snug in a channel will help keep them steady. The channel will also come in useful when cutting the strips to length.

We began by cutting two same length pieces of wood to form the sides of the channel, and clamping these in a workbench. In order for the drill bit to reach into the channel sufficiently to drill holes in the brass, we needed to use a wood plane to chamfer the inner edges of the pieces, enabling the chuck to go down further.

One of the wooden pieces was then aligned flush with the edge of the base, and screwed firmly into position. The second piece cannot be affixed to the base until I have the brass strips to gauge the necessary distance, so that’s it for now. Fortunately, I have plenty to get on with in the meantime.


  1. Very interesting! I'm looking forward to seeing your puppet take shape!

  2. Thanks! Sourcing the brass components is a little tricky unfortunately (I've had to buy the beads from the US, and shall need to order some K & S strips at .093" thick). Hopefully they don't take long to arrive! I cannot progress too far without them!