Detachable Armature Coupling System — A modular armature construction method developed by Peter Forster utilizing industrial tie-rod ends, threaded couplings, telescoping square tubing, and removable mechanical joints to simplify mold making and armature extraction in large-scale sculpture. The system is designed to allow portions of the internal steel framework to be disassembled and withdrawn cleanly from the clay model during mold separation, greatly reducing damage to the sculpture.

Light-gauge square steel tubing is especially well suited for this purpose because it telescopes easily, allowing one tube to function as a removable sleeve coupling within another. Square tubing also accommodates a wide range of square bar dimensions while resisting rotational movement more effectively than round stock. In practical studio use, square tubing is often more economical and structurally efficient than round tubing, which can become prohibitively expensive in larger diameters.

The system commonly incorporates welded nuts, threaded rod ends, tie-rod couplings, removable sleeves, and standardized industrial fittings. Anti-seize compound may be applied to threaded areas during welding and assembly to prevent seizure and permit later disassembly. Magnets can be used effectively during fabrication to temporarily position steel members while welding.

Successful implementation of the system depends greatly upon forethought during the armature design stage. Wherever steel penetrates or protrudes through the clay form, consideration must be given to how those components will later be removed once the mold is constructed. The method reflects an integrated understanding of sculpture, welding, engineering, mold making, and foundry practice.