DexKosu · Material Guide
Resin is how you get ten identical gems, a crystal-clear glowing core, or a rigid part that is lighter and sharper than anything you can print. Silicone mould, measured pour, cure, demould. The technique is simple; the discipline is in the safety gear and in measuring accurately.
Each item lists 4–6 retailers in best-price order. Prices are typical street prices for the size a cosplayer usually buys — always confirm at checkout. DexKosu.com earns a small commission on some retailer purchases. Prices last reviewed ; the best-price order updates itself whenever a price is re-checked.
Two-part polyurethane or epoxy resin
Polyurethane cures fast and opaque; epoxy is slower, clearer and better for gems.
Platinum-cure silicone
For moulds taken off a printed or sculpted master.
Digital scale + graduated cups
Resin is unforgiving about ratio. Measure by weight, not eyeballed volume.
Nitrile gloves + respirator
Non-negotiable. Uncured resin sensitises skin and lungs permanently.
Mould release
Saves the mould and the part on every pull after the first.
Pigments, pearl-ex, alcohol inks
Tint before the pour; surface paint never looks like a cast gem.
The same core supply at 5 retailers, cheapest first. Prices are typical street prices — confirm quantity and shipping at checkout. Links marked * earn DexKosu.com a small commission.
| Retailer | Approx price | Quantity | Shipping | Est. delivery | Price checked | Buy |
|---|---|---|---|---|---|---|
| ★ ALIEXPRESS | ≈$22 | Small AB kits | Cheap/free · 2–5 weeks | 2–5 weeks | Shop* | |
| EBAY | ≈$32 | Trial sizes | Varies by seller · often free | 3–10 days | Shop* | |
| AMAZON | ≈$40 | Gallon-ish kits | Free 1–2 day with Prime | 1–2 days | Shop* | |
| SMOOTH-ON | ≈$45 | Smooth-Cast trial units | Hazmat rules on some resins | 5–10 days (hazmat may add time) | Shop | |
| SKS PROPS | ≈$55 | Prop-shop stocked | Calculated US shipping | 4–8 days | Shop |
Consumables, finishing products and hardware called out in the build order and tips above — again in best-price order.
Clear casting resin
Gems, cores and glowing parts.
Pressure pot or vacuum chamber
Bubble-free clear castings.
Polishing compound + micromesh
Wet-sand to 2000 then polish for glass clarity.
Mould box materials
Foam board, LEGO or acrylic for block moulds.
LEDs to backlight gems
Diffused single LEDs behind clear castings.
Ventilation fan
Never cast in a closed room.
The mould copies everything, including layer lines and fingerprints. Sand and prime the master to the finish you want on the final part before you touch silicone.
A one-part open-face mould works for flat-backed gems and trim. Anything undercut needs a two-part block mould with registration keys and a pour spout.
Weigh both parts, mix for the full stated time, and scrape the sides and bottom of the cup. Under-mixed resin cures tacky forever and cannot be rescued.
Pour in a thin stream down one side so air can escape. A pressure pot gives glass-clear castings; a warm hairdryer pass or toothpick will pop most surface bubbles on a budget.
Demould at the stated time but leave the part 24-48 hours to reach full hardness before sanding or drilling. Green resin tears instead of cutting.
Wet-sand clear parts to 2000 grit and polish for glass clarity, or prime and paint opaque parts as you would a print. Backing a clear gem with foil or a diffused LED sells the glow.
41 full build guides in the archive involve resin casting. Each one walks the whole costume — planning, makeup, sewing, props, paint and wear-day prep.
Superman / DCU
Skill: Advanced
Frieren: Beyond Journey's End
Skill: Intermediate
Batman Universe
Skill: Advanced
Superman / DCU
Skill: Advanced
Jujutsu Kaisen
Skill: Intermediate
Marvel / MCU & X-Men
Skill: Advanced
Hatsune Miku / Vocaloid
Skill: Intermediate
Batman Universe
Skill: Advanced
Chainsaw Man
Skill: Intermediate
Batman Universe
Skill: Advanced
Batman Universe
Skill: Advanced
League of Legends / Arcane
Skill: Intermediate
Chainsaw Man
Skill: Intermediate
Dandadan
Skill: Intermediate
Batman Universe
Skill: Advanced
KPop Demon Hunters
Skill: Intermediate
NieR: Automata
Skill: Advanced
Resident Evil
Skill: Intermediate
Batman Universe
Skill: Advanced
Chainsaw Man
Skill: Intermediate
Invincible
Skill: Intermediate
Undertale / Deltarune
Skill: Intermediate
Five Nights at Freddy's
Skill: Expert
Jujutsu Kaisen
Skill: Intermediate
Printable STL props, armor, and helmets across the model marketplaces.
It is safe with the right precautions: nitrile gloves, a fitted respirator with organic vapour cartridges, eye protection and real ventilation. Never cast in an unventilated living space, and never handle uncured resin bare-handed.
A clear epoxy casting resin. It has a longer working time and cures far clearer than fast polyurethane, which is what you want for gems, cores and lenses. Tint with alcohol ink or pearl pigment during the mix.
Pour thinly down one wall of the mould, warm the resin slightly before mixing, and de-gas or pressure-cast if you have the equipment. For small parts a quick pass with a heat gun or a toothpick clears surface bubbles.
Yes, and it is the most common workflow. Print and finish a master, take a silicone mould from it, then cast as many copies as the build needs — much faster than reprinting each one.
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