Cast and Paint Plaster Dinosaurs
An adult casts plaster dinosaurs in moulds, they set overnight, then children paint their own dinosaurs — or skip casting with ready-made plaster pieces.
By WonderCraft Kids Editorial Team, Editorial team · Updated 5 October 2026
Plaster dinosaur painting is a two-part dinosaur craft for kids aged 3 to 7. First an adult casts dinosaur shapes from plaster in silicone moulds and leaves them to set for at least two hours — overnight is best. Then children paint their own plaster dinosaurs in whatever colours they like. Because the dinosaur already looks impressive, children can focus on colour and pattern rather than drawing. If you would rather skip casting, ready-made plaster dinosaur pieces let you go straight to the painting part.
What you need
- For casting (adult only): plaster of Paris, silicone dinosaur moulds, water, a disposable mixing cup or old jug, and a stirring stick
- Or instead: ready-made / pre-cast plaster dinosaur pieces or a paint-your-own plaster kit
- Paint: washable poster paint for younger children, or acrylic paint for brighter colours
- Small and medium paintbrushes
- A palette or paper plate and a water pot
- Newspaper and a wipe-clean mat
- Watered-down PVA glue for a protective finish (optional)
Step by step
- 1
Adult step — mix the plaster: in a ventilated area, an adult mixes the plaster exactly as the packet directs. Keep the dry powder and the mixing area away from children.
- 2
Adult step — fill the moulds: pour the plaster into the moulds and tap the mould gently on the table to release air bubbles. Leave for about 40 minutes until firm.
- 3
Adult step — unmould and let it set: pop the dinosaurs out and leave them to dry for at least two hours; overnight gives the best surface for painting. They are ready when they feel cool, dry and hard.
- 4
Child step — set up a painting station: put out a few colours with one brush per colour so there is less rinsing.
- 5
Child step — paint the base coat: paint each dinosaur all over in one colour and leave it for about ten minutes.
- 6
Child step — add details: add spots, stripes, scales, eyes and teeth with a smaller brush. Once fully dry, an adult can brush on thinned PVA glue for a tougher shine.
What kids learn
Watching a material change
Children can watch from a distance as runny plaster turns hard in the mould, and notice that the finished piece is solid.
Patience across sessions
Casting one day and painting the next introduces the idea of a project with stages and waiting time.
Careful brushwork
Painting into the small ridges and scales gives children a chance to practise slower, finer brush movements than painting on paper.
Make it easier
Use ready-made plaster dinosaur pieces so the whole activity is painting. Offer three colours and thick brushes for younger children.
Make it more challenging
Ask older children to look up a real dinosaur, paint their plaster dinosaur in its possible colours, and write a small museum label. Or set up a painted dinosaur small-world scene with sand and stones.
Safety and supervision
- Plaster casting is an adult job. Mix plaster in a ventilated area, avoid breathing in the dry dust, and keep powder away from children's eyes and faces.
- Plaster warms up as it sets. Children should not touch, hold or put fingers into wet plaster or the mould until it is fully set and cool.
- Never pour plaster down the sink — it can set in the pipes. Let leftovers harden and put them in the bin.
- Use non-toxic paint and check the age guidance; acrylic paint does not wash out of clothing.
Adult supervision is required for every activity on this site. Read our full child safety guidelines.
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Frequently asked questions
How long does plaster take to set before painting?+
It is usually firm enough to unmould in about 40 minutes, but leave it at least two hours before painting. Overnight gives the best, driest surface.
Can children help make the plaster?+
Mixing and pouring plaster should be done by an adult. Children can watch from a safe distance and do all of the painting once the dinosaurs are fully set and cool.
Can I skip the casting?+
Yes. Ready-made plaster dinosaur pieces or a paint-your-own plaster kit let you go straight to painting in a single session.
What paint is best for plaster dinosaurs?+
Poster paint soaks in well and is easy for younger children. Acrylic paint gives brighter colours but does not wash out of clothes.
