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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6 guidesSTL to mold: turn any 3D model into a printable mold
The whole pipeline on one page: upload an STL, generate a two-part mold with parting line and alignment keys, print it, cast it. Plus which of the mold tools fits your project.
How to make a cast of any object
From "I have a thing" to "I have a copy of the thing" in five steps, and why plaster is the material to start with.
Free mold making software: what actually works
The four categories people confuse for each other, which one fits your job, the free Blender boolean method written out, and where AI genuinely helps.
Mold box generator: a printable silicone mold box from any STL
What a mold box actually is, how much silicone to leave around the master, and when a hugging shell beats a box outright.
Moldboxer alternative: a free mold box generator in your browser
Which Meshcast tool replaces which feature, the silicone-saving hugging shell, and an honest list of where desktop software still wins.
Can you 3D print candles?
You don't print the wax, you print the mold. What actually works, what doesn't, and the safe way to get a custom-shaped candle.
3D printed guitar picks: do they work?
Honest answer by filament: PLA is too brittle, PETG is decent, Nylon plays like the real thing. Plus thickness by playing style.
Cast a material
13 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.
Custom soap molds: design & print your own
Generate a soap mold in any bar shape, print it, and release clean bars, melt-and-pour or cold-process.
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 press mold
Design a reusable die + piston press mold, print it in PLA or PETG, pack the mix, clay, soap, bath bomb powder, and press out a clean shape 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 photo candle mold
Wrap a photo around a candle as a lithophane and cast it from a printed two-part mold. The picture glows when the candle is lit.
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.
Adaptive silicone molds: use less silicone
Print a shell that hugs your model instead of a big box, then pour a silicone mold using a fraction of the material.
Carbon fibre molds you can 3D print
Print a rigid female mold for hand-laid carbon fibre, with the surface prep, release and demolding steps that decide the finish.
Maker projects
10 guidesCustom cookie cutters: design & 3D print any shape
Turn any outline into a printable cookie cutter, sharp cutting edge, sturdy handle, and the honest answer on PLA food contact.
3D printed stamps that print crisp
Make a custom stamp with mirrored text handled for you, which material picks up ink, and which embosses clay and soap.
3D printed keychains: names, logos & mini models
Text keychains and shrunken-STL charms, plus the two-color filament-swap trick and how to keep the loop from snapping.
3D printed planters: drainage & materials
Generate a planter that actually keeps plants alive, drainage done right, and which filament survives wet soil.
How to make a lithophane from a photo
Turn any photo into a backlit 3D print, the contrast, thickness and print settings that separate a crisp portrait from a striped smudge.
Texture rollers: press patterns into clay
Print a patterned roller and roll a repeating texture into clay slabs, with the layer height and release tricks that keep it crisp.
Paper embossers: press your design, no ink
Print a matched die pair that squeezes a raised impression into paper, for stationery, cards and book plates.
Name signs and door plates
Turn text into a printable sign, including two-colour lettering and how to mount it once it is printed.
Packaging inserts that protect fragile prints
Print a case that cradles a fragile part in a soft impression so it survives the post, with hinged, two-part and tray options.
Golf ball stencils and alignment lines
Print a cap that clips onto a ball and mark your initials, a logo or an aiming line the same way every time.
Turn any photo into a custom soap dish
Upload a picture and cut it into the drainage pattern of a two-part soap dish, a tray plus a perforated insert that keeps the bar out of standing water.
Print & design
6 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.
Split an STL for printing
Model bigger than your bed? Cut it into printable pieces with clean joints, and glue it back invisibly.
Reduce STL file size without losing detail
Scans and sculpts produce bloated meshes. How far you can decimate before it shows, and how to repair broken files.
Workflow
5 guidesWhat to do with failed 3D prints
Press a bin of old PLA into coasters, tiles and trays. Why molten PLA cannot be poured, which mould survives the heat, and a calculator for how much shred a part needs.
Mold 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.
Silicone mold not curing: sticky, tacky or soft
Tell cure inhibition from a bad mix in one look. What poisons platinum silicone, why resin-printed masters are usually the cause, and the barrier coat that fixes it.
Plaster cracking, crumbling or not setting
Water-to-powder ratio by weight, demold time vs cure time, why thin sections crack first, and the two rules that flip for concrete.
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.
Can't confirm your account, or find your download?
Why Yahoo and Outlook break one-time confirmation links before you click them, what to do when a paid plan still shows free limits, and where your browser put that STL.
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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