Materials, tools, armature and studio safety
This domain tests your command of what each material can and cannot do, the tools that suit it, how an armature carries weight, and whether you can work without harming yourself or others.
Materials and their behaviour
- Clay: earthenware for low-fire terracotta; stoneware and porcelain for higher vitrification. Plasticine and modelling wax stay workable and never dry - useful for maquettes and waste-mould originals. Clay shrinks on drying; thick solid masses crack.
- Plaster of Paris: mixed by sprinkling plaster into water (roughly 2:1 plaster to water by weight), slaked, then stirred; sets with an exotherm.
- Wax: microcrystalline or beeswax for lost-wax models; melt in a double boiler.
- Wood: carve with the grain, using gouges, mallet and vice; green wood moves.
- Stone: soapstone and sandstone are soft enough for school tools; marble needs harder abrasives; always cut with a respirator and water suppression.
- Metal: casting, chasing and welding; treat as demonstration-only in a school workshop unless properly equipped.
Tools and armature
A modelling stand with a pipe and board, aluminium wire, newspaper or foil for bulk, wooden and loop tools, kidney, spatula, calipers, turntable, plaster bandage. Build the armature slightly smaller than the finished figure and anchor it firmly, because wet clay is heavy.
Safety rules
Silica dust causes silicosis: never sweep dry clay or plaster, use wet cleaning and an N95 mask. Plaster burns skin as it sets - never cast a hand or face directly. Ventilate solvent and wax fumes; keep sharp tools sheathed; wear goggles when chiselling stone.
Worked example
A standing figure 60 cm tall needs more than a single wire: a flange-clamped pipe as spine, aluminium wire for limbs, crumpled newspaper to bulk out the torso, and cross-wires at the shoulders and hips. Test that it stands before adding clay; a weak armature will lean as the clay dries.
Traps
Pouring water into plaster; washing plaster down the sink; armature that shows through the surface; iron wire that rusts and stains clay.