How to cast resin at home (beginner guide)

Casting resin at home comes down to five steps: choose a resin, get a mold, mix it carefully by the manufacturer's instructions, pour and clear the bubbles, then let it fully cure before demolding. The most forgiving setup for a beginner is a flexible silicone mold, which releases cleanly and captures fine detail. Work in a well-ventilated space with gloves on, and you can make crisp resin castings on your first try.

What you'll need

• Casting resin (epoxy or polyurethane) and its hardener.
• A mold — a flexible silicone mold is the easiest place to start.
• Mixing cups and stir sticks, and a scale or graduated cups for accurate ratios.
• Safety gear — nitrile gloves, eye protection, and good ventilation.
• Optional: mold release, a heat gun or pressure pot for bubbles.

Choose your resin

Two families cover most home casting:

• Epoxy resin — clear, forgiving, and slower to cure, which makes it beginner-friendly for solid castings and pieces where clarity matters.
• Polyurethane (casting) resin — cures faster and is economical for larger or repeat casts, but it's more sensitive to moisture, so it wants a dry mold and dry conditions.

Whichever you pick, the manufacturer's datasheet is the source of truth for mix ratio, working time, and cure — settings vary between products, so don't rely on generic numbers.

Get a mold

You cast resin into a mold, so that's your first build. Two routes:

• Silicone mold (recommended for resin): print a box with the silicone mold box generator, pour silicone into it to make a flexible mold, then cast resin in that silicone. Silicone flexes to release the cast, handles undercuts, captures fine detail, and lasts for many pours — ideal for resin. See how to make a reusable silicone mold box.
• Two-part printed mold (best for simpler casts): the two-part box mold generator makes a rigid mold you pour into directly. It's quick and cheap and suits wax and candles especially, plus simple resin shapes that pull apart cleanly along a seam.

Not sure which fits your project? Compare them in which mold to print.

Safety first

Resin chemistry deserves respect. Work in a well-ventilated area, wear nitrile gloves and eye protection, and keep resin off your skin — wash with soap and water if it makes contact. For repeated or larger pours, a respirator rated for organic vapors adds a margin of safety. Keep it away from food surfaces and utensils, and follow the safety notes on your product's datasheet.

Mix it right

Accurate mixing is the difference between a hard, clear cast and a sticky mess. Measure the resin and hardener to the exact ratio on the label — by weight or volume as specified — and stir thoroughly, scraping the sides and bottom so no unmixed resin is left. Mind the pot life (working time): once it's mixed, the clock is running, so pour before it starts to thicken.

Pour and remove bubbles

Pour in a thin stream from one corner and let the resin flow across the mold — this drives air out ahead of it instead of trapping it. To clear bubbles that remain:

• Heat: a gentle pass with a heat gun (or a quick breath of warm air) brings surface bubbles up to pop — keep it moving so you don't scorch the resin.
• Pressure pot: for bubble-free clarity, curing under pressure compresses any trapped air until it's invisible.
• Patience: tapping the mold gently on the table also coaxes bubbles to the surface.

Cure and demold

Let the cast reach full cure on the datasheet's timeline before you touch it — pulling it early leaves it soft and prone to distortion. A little mold release beforehand makes demolding easier, though a flexible silicone mold usually releases with a gentle flex. Ease the piece out, and give it any additional cure time before sanding or finishing.

Troubleshooting

• Sticky or soft cast: almost always an off ratio or under-mixing — measure precisely and stir thoroughly next time.
• Lots of bubbles: pour thinner and slower, warm the surface, or cure under pressure.
• Cast won't release: use a mold release, or wait for a full cure before demolding.
• Cloudy polyurethane: moisture is the usual culprit — dry the mold and work in low humidity.

FAQ

Epoxy or polyurethane resin?

Epoxy is the friendlier starting point — clear and slow-curing. Polyurethane cures faster and costs less for bigger or repeat casts, but it's fussier about moisture.

Why is my resin still sticky?

The mix ratio was likely off or it wasn't stirred enough. Measure exactly as the label says and mix thoroughly, scraping the sides and bottom.

How do I get rid of bubbles?

Pour in a thin stream from a corner, pass a heat gun gently over the surface, and for glass-clear results cure in a pressure pot.