In-depth guides on casting candles, soap, resin and plaster, making silicone molds, and which filament to use. Search above, or jump to a section from the list on the left.
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9 guidesHow to cast plaster, jesmonite & concrete
The most forgiving material to start with. Covers mix ratios, the right release agent for each binder, how to seal two-part mold halves without leaks, and what makes jesmonite different from standard plaster.
How to make a silicone mold from a 3D print
Print a rigid housing, mix and pour silicone, degas and demold - plus pour gaps, shore hardness and a troubleshooting list.
How to make a candle from a 3D-printed mold
Wick sizing, pour temperatures by wax type, how to demold without cracking, and a one-page troubleshooting chart.
Cold-process soap in a printed mold
Lye safety, tracing to the right consistency, gel-phase management, and how to demold and cure a custom-shaped bar in 6 weeks.
How to cast resin in a 3D-printed mold
Choosing between epoxy and polyurethane, managing exotherm so your mold doesn't warp, mixing ratios, and demolding without tearing.
How to make silicone ice cube molds
Use a 3D-printed positive to cast food-safe silicone ice molds at home, including how to get perfectly clear ice.
How to make a bath bomb mold
Design a reusable two-part press mold, print it in PLA or PETG, pack the mix, and press out clean spheres every time.
How to make a candle mold
Design and 3D print a reusable two-part candle mold with a wick hole, then pour wax and release a clean candle.
How to make a custom ice cube tray mold
A multi-cavity mold plus a flexible silicone caster - for ice, chocolate, gummies, wax melts and resin embeds, in any shape.
Print & design
4 guidesPLA vs PETG vs PP vs TPU: which filament should you use?
The practical answer: when PLA is fine, when to switch to PETG, what PP actually gives you that other plastics don't, and why TPU molds are underrated. Includes a comparison table by casting material.
Silicone molds vs direct-print molds
When a $5 plaster pour into a PLA mold is the right call, and when to invest the extra hour casting a silicone intermediate. Covers durability, detail, cost, and heat resistance.
Best print settings for 3D-printed molds
Layer height, wall count for watertightness, infill, temperature, speed and orientation - tuned per casting material so your molds don't leak.
Draft angles & undercuts: molds that release
How much taper to design in, how to spot undercuts, where to put the parting line, and when to split the mold or go flexible.
Workflow
3 guidesMold release agents: the complete guide
Which release agent to use for resin, silicone, plaster, concrete, soap and wax in a printed mold - how to apply it, homemade options, and the mistakes that ruin a cast.
Casting troubleshooting: symptoms, causes & fixes
Bubbles, sticking, cracking, incomplete fill, rough surface, warping and seam leaks - the likely cause and the fix for each.
Are 3D-printed molds food-safe?
The honest answer, food-safe coatings and their limits, and the reliable path: print a master and cast food-grade silicone.
Frequently asked questions
What filament should I use for molds?
PLA is the default for low-temperature pours: soap, plaster, jesmonite, concrete, cold-curing resin. For hot candle wax (paraffin, soy at 70–80 °C) or warm-exothermic resin, switch to PETG. PP makes a naturally release-y mold but is hard to print. Avoid ABS for food-adjacent work. Full breakdown: filament comparison →
What filament is best for keychains, stamps and charms?
For keychains and nameplates: PETG for durability, PLA for crisp detail with light use. For stamps: TPU 95A for the stamp face (flexible, picks up ink well) and PLA/PETG for the handle. For shoe charms: TPU 95A for the best snap-in fit. Guitar picks: PETG or Nylon for the right flex, as PLA is too brittle.
Are 3D-printed PLA molds food-safe?
No. Layer lines trap bacteria and most filaments contain non-food-grade additives. For ice cubes, chocolate, or anything edible: print the mold in PLA, pour platinum-cure food-safe silicone into it, then cast your food in the silicone copy. See the silicone & ice-cube guide →
Can you cast resin directly into a PLA mold?
Yes, with caveats. Use a release agent (PVA spray or mold-release wax), keep wall thickness above 2 mm so exotherm doesn't deform the print, and design 3–5° of draft on every vertical wall. For repeat pours or complex geometry, cast silicone in the PLA first and use the silicone as the working mold. Full resin guide →
How do I stop my cast from sticking to the mold?
Three fixes in order. (1) Add draft: every vertical wall should taper 2–5° so the cast lifts cleanly. (2) Use the right release agent: mineral oil for soap, PVA or wax for resin, silicone spray for plaster and jesmonite. (3) Print stronger: at least 3 perimeters and 30% infill so the mold flexes slightly on demold without cracking.
What layer height gives the smoothest surface finish?
0.12 mm gives a near-glossy cast. 0.16 mm is the speed/finish sweet spot for most tools. 0.20 mm shows visible lines on the cast, fine for plaster or rustic concrete, not for resin jewellery. You can also sand the mold interior with 400 → 800 grit before pouring to eliminate layer lines entirely.
How do I print in two colors for nameplates and keychains?
The easiest method: slice the model and find the layer number where the raised text or inlay starts. Insert a filament change (M600 or pause at layer) at that height in your slicer. When the printer pauses, swap to your second color and resume. No multi-material upgrade needed. For keychains, the text inlay is typically 1–2 layers above the base plate.
Do I need a two-part mold or a one-piece mold?
One-piece (open-top) molds work for shapes with a flat top and no undercuts: candles, soap bars, ice cubes, tiles. Use a two-part mold when the cast has undercuts (figurines, knobs, anything with a "waist") or when both faces need to be smooth. Two-part molds need alignment keys and a clamping plan, and the Meshcast generator handles both automatically.
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