Active materials for experiments 001–007, with firing reference, clay composition guide, shopping list, and future process materials.
| Material | Supplier | Use | Notes |
|---|---|---|---|
| Witgert 5041-25 Gietkleipoeder 300 | De Hazelaar / Witgert | Base material — all current experiments | Red earthenware. SiO₂ 68.7%, Al₂O₃ 18.3%, Fe₂O₃ 5.2%, LOI 5.0%. Fire 950–1100°C oxidation. ~5–7% total shrinkage. |
| Material | Supplier | Use | Notes |
|---|---|---|---|
| Agar agar powder (food-grade) | Albert Heijn / online | Agar gelcasting (exp-004, 005) | 1–3 wt% of agar/water solution. Dissolve >85°C, gels <35°C. Thermoreversible. Burns out 250–350°C cleanly. |
| Corn starch | Albert Heijn | Starch consolidation (exp-002, 003) | 7–10 wt% of dry ceramic. Gelatinises >80°C. Burns out 300–500°C. Zero cost. |
| Material | Supplier | Use | Notes |
|---|---|---|---|
| Darvan 811 | Seladon.be / ceramic suppliers | Deflocculant for all slip casting | 0.3–0.6 ml per 100g dry ceramic. Keeps slip fluid at high solids loading (55–65 wt%). Do not exceed — causes flocculation above optimum. |
| Silica flour, 200 mesh | De Hazelaar | Body filler in all slip formulas | 10 wt% of dry ceramic. Improves fired density and reduces shrinkage variation. |
| PVA (polyvinyl alcohol) | Lab / craft supplier / Amazon.nl | Green body binder — freeze casting (exp-006, 007) | 0.5–1 wt% of dry ceramic. Dissolved in water before slip prep. Bridges particles after ice sublimation — without it, freeze-cast green bodies are extremely fragile. Burns out 250–350°C cleanly. Not needed for agar or starch experiments. |
| Methylcellulose (MC) | Food supplier (e.g. Sosa, Texturas) / lab supplier | Alternative green body binder — freeze casting; also relevant for extrusion | 0.5–2 wt% of dry ceramic. Less toxic than PVA, biodegradable, cellulose-derived. Reverse-gelling: dissolves in cold water, gels >60°C. Interchangeable with PVA at similar concentrations. Burns out 250–400°C. Available cheaply from molecular gastronomy suppliers. |
| Glycerol | Pharmacy / lab supplier / Amazon.nl | Ice crystal modifier — freeze casting | Gets excluded from the ice front as crystals grow, altering local growth kinetics and lamellar spacing. Non-toxic, food-safe. Try 0.5–2 wt% of slip. Also a mild plasticiser for the binder phase. |
| PEG (polyethylene glycol, MW 400–1000) | Lab supplier / Amazon.nl | Binder + ice crystal modifier — freeze casting | Widely used in freeze casting literature as a dual-function additive. Low MW PEG (400) is liquid at RT; higher MW is waxy solid. 0.5–2 wt%. Modifies crystal morphology and bridges particles in green body. |
| Sucrose (table sugar) | Albert Heijn — effectively free | Mild ice crystal modifier — freeze casting | Small molecules get partially excluded from ice front, mildly altering crystal morphology at 1–5 wt%. Effect is subtle but non-zero and cost is zero. Worth including in a test run for comparison. |
| TPM (tripropylene glycol monomethyl ether, Dowanol TPM) | Chemical / coating supplier (e.g. Sigma-Aldrich, VWR) | Cosolvent + ice crystal modifier — freeze casting | Used in combination with PVA + water in freeze casting slip. Acts as cosolvent: depresses freezing point slightly and gets excluded from the advancing ice front, enriching the liquid interlayer between crystals. Results in finer, more controlled lamellar pore structures. Relatively low toxicity for a glycol ether. Typical use 2–10 wt% of water phase. Removed during sublimation/freeze drying along with water. |
| CuCl₂·2H₂O (copper chloride dihydrate) | Lab / chemistry supplier | APD additive — freeze casting (exp-006, 007) | Optional. 1 wt% of slip. Per Wu et al. (2023) — promotes liquid-phase structure preservation during ambient-pressure drying. Effect on clay (vs. fine alumina) is speculative. |
| Material | Supplier | Use | Notes |
|---|---|---|---|
| Platinum-cure silicone, Shore A30 (Mold Max 30) | FormX.nl | Flexible two-part molds — all gelcasting experiments | Shore A30 is soft enough for undercuts, rigid enough to hold fine detail. 500g kit makes one ribbed tile mold. Life: 20–100 pours. Best option for fine features and fragile green bodies. |
| PCL pellets (polycaprolactone) — bulk | AliExpress / Amazon.nl | Thermoplastic rigid molds (simple geometries) | Softens at 60°C in hot water, moldable by hand, sets rigid at room temp. Reusable indefinitely. ~€15–20/kg bulk. Same base material as Green Stuff World Flexi Mold. NOT flexible — design split molds with no undercuts. Avoid for fragile green bodies. |
| "Oogoo" DIY silicone (silicone caulk + cornstarch) | Gamma / Praxis (neutral-cure caulk) | Cheap flexible molds for simple shapes | Mix 100% neutral-cure silicone caulk + cornstarch 3:1 by weight. Press around master, sets flexible in ~30 min. ~€5–8 per mold. Flexible like silicone — peel-able. Lower detail and shorter life than Mold Max 30. Good for quick prototyping. |
| Copper sheet, 3mm | Metal supplier / Amazon.nl | Cold-side thermal conductor — freeze casting (exp-006, 007) | High conductivity needed for directional freezing. 150×150mm for exp-006, 100×100mm for exp-007. |
| PVC pipe (Ø50mm and Ø30mm) | Gamma / Praxis | Cylindrical molds for freeze-cast specimens | Cut to 40mm (Ø50) and 20mm (Ø30) sections. Sealed to copper with silicone sealant. |
| Material | Supplier | Use | Notes |
|---|---|---|---|
| Engobe (slip coating) | Ceramic supplier | Surface colour / texture before firing | Applied to leather-hard or dry greenware. Cone 06–04. |
| Transparent glaze | Ceramic supplier | Weatherproofing and aesthetics | Cone 06–04 (990–1060°C) for terracotta. Not required for feasibility experiments. |
Standard terracotta curve — total cycle 14–24h
| Phase | Rate | Range | Notes |
|---|---|---|---|
| Initial heat-up | 30°C/h | RT → 120°C | Free water removal |
| Dehydration | 60°C/h | 120°C → 350°C | Bound water + binder burnout |
| Burnout soak | Hold 30 min | 350°C | Complete organic burnout |
| Quartz zone ⚠ | 50°C/h | 350°C → 650°C | Critical: quartz inversion at 573°C (~2% volume change) |
| Main heat-up | 100–150°C/h | 650°C → 1080°C | |
| Peak soak | Hold 1–2h | 1000–1080°C | Uniform sintering |
| Initial cool | 80°C/h | Peak → 650°C | |
| Quartz cool ⚠ | 50°C/h | 650°C → 500°C | Just as critical in reverse |
| Final cool | 100–200°C/h | 500°C → RT |
How oxide analysis affects slip and fired properties — reference for Witgert 5041-25 and future clay choices
| Oxide | Witgert value | Effect on fired body | Effect on slip |
|---|---|---|---|
| SiO₂ (68.7%) | High | Lower vitrification temp, more glassy body; quartz inversion at 573°C governs firing curve | Little direct effect |
| Al₂O₃ (18.3%) | Moderate | More refractory and stronger; too much → underfired at 1000°C | Less plastic; needs more deflocculant |
| Fe₂O₃ (5.2%) | Typical earthenware | Red/brown colour in oxidation; lowers vitrification slightly | Little effect on viscosity |
| Fluxes — K₂O 2.3%, Na₂O 0.2%, CaO 0.2%, MgO 0.4% | Low-moderate | Promote densification and glass phase; CaO can cause lime popping if coarse | Alkalis increase deflocculation sensitivity |
| LOI (5.0%) | Normal | Organics burn out 300–600°C; fast firing traps gas → bloating or black core | N/A — measured on dry powder |
Everything needed to run experiments 001–007 and all testing procedures. Items you likely already own (oven, freezer, pot, camera) are excluded.
Materials for processes not yet in active experiments — LPCIM, geopolymer, and advanced mold systems.