ForMatter/Processes/formative/Investment Casting (Lost Wax)

proc_investment_casting_lost_wax

Investment Casting (Lost Wax)

formative · lost-wax casting, cire perdue, investment casting, precision casting

highlast updated 2026-04-27

Carve or print a wax model of the part you want, surround it with a refractory plaster slurry (the "investment"), bake the wax out, and pour molten metal into the cavity left behind. The casting workflow that has produced bronze sculpture and gold jewelry for at least 5000 years, and the workflow most contemporary fine jewelry still flows through. The wax sets the shape; the metal copies it.

Single-use ceramic-shell or plaster-mold casting process. Steps: (1) sculpt or 3D-print wax model; (2) attach to wax sprue tree; (3) flask and invest with gypsum-bonded refractory slurry; (4) burn out wax in furnace at 730–800 °C; (5) pour metal (gravity for jewelry, vacuum-assist for thin sections, centrifugal for high-temperature alloys); (6) quench and break out. Tolerances 0.1–0.5 mm depending on alloy and part size. The dominant route for fine-jewelry production and aerospace turbine-blade casting alike, scaled by alloy and equipment.

Scale & Tolerance

scale (mm)1 – 1500
tolerance (mm)0.2
skillintermediate to advanced — wax pattern creation, sprue layout, burnout / pour timing all require trained judgment
costmoderate per part; capital cost moderate-to-high

Equipment

school_shopburnout kiln + vacuum or centrifugal casting machine + investment + flask
professionalproduction casting house with semi-automated wax injection, batch burnout, and induction-melt vacuum casting
industrialaerospace investment-casting foundry with ceramic-shell investment and high-temperature alloy capability

Environmental

energy_usemoderate (burnout kiln + induction melt)
waste_streaminvestment plaster (single-use), spent ceramic shell, metal scrap (recovered)
consumableswax, investment powder, flux

Compatible materials

Fine Silver (999)

Sterling Silver (925)

18k White Gold (Palladium-Whitened)

Platinum 950 (Pt950)

Palladium 950 (Pd950)

Aluminum A356 (Cast)

Titanium Grade 5 (Ti-6Al-4V)

Citations

url · https://en.wikipedia.org/wiki/Investment_casting
book · Untracht, *Jewelry Concepts and Technology* (Doubleday, 1982), lost-wax casting chapter pp. 309–354.
book · Lefteri, *Making It: Manufacturing Techniques for Product Design*, 2nd ed. (Laurence King, 2012), 'Investment Casting' p. 12.

Concordance

House vocabulary — terms ForMatter uses with intent.

anisotropic: Direction-dependent. Wood reads differently along the grain than across it; rolled steel is stiffer along the rolling direction. The Principled-BSDF anisotropic input rotates the highlight to match.
application: What the thing IS, in the world. The third entity, peer of material and process. A water bottle, a chair, an extruded-aluminum profile.
BRDF: Bidirectional Reflectance Distribution Function. The math behind how a surface returns light for any incoming and outgoing direction. The PBR model is a parameterized BRDF.
channeled: A voice block written within a dead author's philosophy, marked and cited. Distinct from a verbatim quote. Roland Barthes channeled on PMMA reads like Barthes; the citation attributes the lineage.
choral fugue: ForMatter's register. Subject stated plainly (freshman tier), answered in technical and sensorial registers, countersubjects from linked processes and applications, citations as final stretto. Voice blocks where canon attaches.
clearcoat: A second specular layer over the base surface. Glossy plastics and lacquered woods get a clearcoat term in the PBR table. IOR 1.5 by default.
compatibility (process): Each process entry lists which materials it can work. The cross-ref renders as sphere pills so the gallery feeling extends inward.
confidence: Each entry tagged high / medium / low. A senior's low-confidence-with-three-citations beats a freshman's high-confidence-with-none. The label is a contract with the reader, not a brag.
crystalline (finish): A faceted-surface read — gemstones, glassy minerals, ice. Drives PBR defaults: IOR 2.42 (diamond), transmission 1.0, low roughness.
derive_pbr(): The build's single source of truth — sphere palette + finish enum → Principled-BSDF starter values. One function feeds the entry-page table, the per-host snippets, the glTF export, and the Three.js Live Preview.
freshman / senior register: Two registers in every entry — the plain freshman description and the technical / sensorial one. Same database, two readers, no extra subscription.
glTF: GL Transmission Format — the open 3D-asset standard every modern app reads. ForMatter emits a .gltf material doc per material. Open standard, designer-friendly handoff.
IOR: Index of Refraction. How much light bends entering the surface. Air 1.0, water 1.33, glass 1.5, diamond 2.42. Drives transmission and the specular term.
iridescent (finish): Hue-shifted accent over base. Anodized titanium and niobium, opal, paraíba. Drives PBR defaults: medium metalness, sheen, clearcoat.
lite-PBR: ForMatter's PBR approach — Principled-BSDF starter values per entry, no measured BRDFs, no commercial assets. Honest reasonable defaults from the finish enum, per-entry numeric overrides where you have a real reason.
Live Preview: The Three.js shader ball that replaces the static CSS sphere on entry pages. Same derive_pbr() values, real-time lit, draggable. Optional — toggle in Preferences.
material: What the thing is MADE OF. The first entity. Aluminum 6061, white oak, soda-lime glass.
metallic (finish): Specular highlight, deep shadow rim. Drives PBR defaults: metalness 1, low roughness, IOR 1.45. Polished steel, gold, copper.
PBR: Physically-Based Rendering. The shading model every modern 3D app uses, parameterized by metallic / roughness / IOR / transmission / clearcoat / sheen. ForMatter publishes starter values for every material entry.
Principled BSDF: Blender's name for the consolidated PBR shader. Most other apps ship the same shader under different names (Standard Surface, ShaderGraph, Substance). One node, every output.
process: How the material is MADE INTO the thing. The second entity. Cast, machined, kerf-bent, anodized, planished, granulated. Process is a peer of material, not a footnote.
quote: A voice block carrying a verbatim quotation from a living author, with citation. Distinct from a channeled block. Living = quote only; the rule is enforced at the schema layer.
roughness: Microsurface scatter. 0 is mirror-smooth; 1 is fully diffuse. Most real surfaces sit between 0.2 and 0.8.
sphere proxy: ForMatter's visible-character stand-in for every material. CSS-gradient driven by the entry's palette and finish, not a baked render. Honest about being a proxy, scales to six hundred entries cheaply, tweakable in one place.
substitute: A peer material that could fill a similar role. Cross-references render as sphere pills inside an entry — the gallery feeling extends inward.
transmission: How much light passes through. 1 is fully transparent; 0 is opaque. Glass, gemstones, clear plastics carry transmission.
voice block: A versal block where a real authored voice attaches to the material or process. Schema-tagged with status (living / dead) and mode (quote / channeled). Citations always.
woodgrain (finish): Directional sheen with grain ring. Drives PBR defaults: anisotropic 0.6, medium roughness, no metalness. Every wood entry.

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ForMatter

Materials and processes for people who design and make things.

A local-first library of materials, processes, and applications, equal weight, citable everywhere. Part of the renato.design ecosystem — sibling of Plenum, Specimen, Ingenue, gesture, graf, and the Renato Rhino plug-ins. Form and matter, inseparable.

Why this exists

Half of teaching materials is teaching how the material is made into the thing. The standard subscription library was always light on that half. The wedge here isn't better samples or a prettier interface — it's treating Process as a peer entity, not a footnote.

Rules of the house

Citations or it didn't happen. Every property number, every claim, every borrowed register has a traceable source.
Living authors are quoted only. Verbatim or not at all.
Dead authors may be channeled within their philosophy — marked, cited, never impersonated.
Confidence labeled honestly. A senior's low-confidence-with-three-citations beats a freshman's high-confidence-with-none.
Local-first. Works offline, no login, no subscription.

Sister apps

Ingenue — five voices argue about what to build from electronic parts. Where ForMatter teaches what the thing is made of, Ingenue proposes what the thing could be.
Plenum — vehicle codes through the camera, doo-wop register.
Specimen — iOS field-collection for design students.
renato.design — the rest.

Sources

Conway's Material World on raw materials, Lefteri's Making It on processes, Untracht and McCreight on metalsmithing, USDA Forest Products Lab on woods, GIA on gemstones, Schott / CoorsTek / Toray / Owens Corning datasheets, MakeItFrom for verifiable property numbers, ASM Handbook, ISO standards. Voice blocks: Barthes, Yanagi, Benjamin channeled within their philosophy; Lefteri verbatim. All cited.

v0.5 — 2026-04-27 · Phil Renato · renato.design · MIT-licensed code, CC BY-NC research content

Preferences

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UI scale Browser-style zoom. Useful for classroom projection or close work.

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