Clay Types NZ — Complete Comparison: Air-Dry, Polymer, Plasticine, Pottery & More

Walk into any NZ craft store and you're hit with five different clays in five different colours. They look similar; they're radically different. This guide compares every clay type you can buy in New Zealand, what each does best, and exactly which one to grab for your next project.

Quick clay comparison

For the impatient, here's the table:

• Air-dry clay — sets at room temperature in 24–48 hours. Big sculpture, school projects, kids.
• Polymer clay — sets in a household oven at 110°C. Jewellery, miniatures, beads.
• Plasticine / oil-based clay — never sets. Practice modelling, stop-motion animation.
• Pottery / ceramic clay — needs a kiln (1000°C+). Bowls, mugs, traditional pottery.
• Paper clay — air-dries lighter than air-dry clay. Detailed sculpture.
• Cold porcelain — air-dries translucent. Cake decoration, fine sculpture.

Air-dry clay — the everyday choice

Air-dry clay (sometimes called air-hardening clay or modelling clay — confusingly, those terms can mean different things) is the everyday Kiwi clay. Mix it, sculpt it, leave it on the bench, 24–48 hours later it's hard enough to paint.

Best for

• Larger pieces (bigger than 10cm) — polymer clay gets expensive at scale
• Kids' projects — no oven, no kiln, no special tools
• NCEA art folio work (Years 11–13)
• Sculpture over wire armatures
• School projects, dioramas, model-making

Limitations

• Not waterproof — sealing required for outdoor/wet use
• Shrinks 5–10% as it dries — expect minor cracks on thick pieces
• Less detail than polymer — finer features blur
• Not food-safe even after sealing

The Mont Marte Premium Air Hardening Modelling Clay 500g is the NZ standard at $5.99. Full polymer vs air-dry comparison here.

Polymer clay — the detail clay

Polymer clay stays soft on the shelf indefinitely. Bake it at 110°C in a household oven for 15–20 minutes and it's rock-hard, sandable, drillable, paintable. Best for small pieces with fine detail.

Best for

• Jewellery (earrings, pendants, beads)
• Miniatures, dollhouse furniture
• Fine sculpture (small busts, figurines)
• Mixed media inserts (resin embeds, mosaic tiles)
• Strong colours and metallics (much more vibrant than air-dry)

Limitations

• Expensive in volume — a $3.49 60g block doesn't go far on big sculpture
• Needs oven — not ideal for kids without supervision
• Can burn at temperatures above 130°C (smells like burning plastic, ruins the piece)
• Not food-safe under any treatment

Mont Marte Make n Bake is the NZ standard. We stock 30+ colours in 60g and 400g blocks. Browse the polymer clay range.

Plasticine / oil-based clay — the reusable practice clay

Plasticine (and other oil-based clays) never dries because the binder is oil rather than water or polymer. It stays workable forever. Great for practice, never for finished pieces.

Best for

• Learning sculpture technique — rework as many times as you want
• Stop-motion animation — the clay needs to flex pose-to-pose
• Mould-making originals — sculpt in plasticine, cast in silicone, throw away the original
• Kids' free-play modelling — cleans off hands and surfaces with soap

Limitations

• Never sets — you can't keep the sculpture
• Greasy residue on hands and surfaces
• Can stain fabric
• Melts in heat (don't leave in a sunny car)

Pottery / ceramic clay — the traditional choice

Real pottery clay needs a kiln to fully set, which most NZ home users don't have. If you're not enrolled in a pottery class with kiln access, this isn't for you yet.

Best for

• Functional pottery (mugs, bowls, plates that you can actually use)
• Glazed work — the traditional shiny glaze finish requires kiln firing
• Pottery classes (most NZ community centres offer them)
• Once-fired pieces with deep tradition behind them

For most NZ home crafters, air-dry clay finished with acrylic paint and a clear sealer mimics the look of pottery without the kiln. Not the same craft but a good substitute.

Paper clay — the lightweight specialist

Paper clay is air-dry clay mixed with paper fibres. The result: dries lighter, takes more detail, and you can carve and rework it after drying. Costs more than standard air-dry. Used by professional sculptors and miniature artists.

Cold porcelain — the cake decorator's choice

Cold porcelain is an air-dry clay that sets translucent like real porcelain. Used for cake-topper figurines, fine sculpture, and miniature flowers. Not actual porcelain — it's a corn-flour-based recipe — but the finish is gorgeous.

Which clay should you choose?

• Sculpting a piece bigger than your hand → Air-dry clay
• Making jewellery or miniatures → Polymer clay
• Kid craft, after-school programmes → Air-dry clay (no oven, larger pieces)
• Stop-motion animation or practice work → Plasticine
• Functional mugs / bowls → Pottery clay (with kiln access)
• Fine detail sculpture you'll paint → Paper clay or polymer
• Cake decoration figurines → Cold porcelain
• NCEA Year 11–12 art folio → Air-dry clay (cheap, scales up)
• NCEA Year 13 final pieces → Polymer for fine detail, air-dry for scale

Pairs well with

Most clay artists also need modelling tools for shaping, acrylic paint for finishing, and a clear acrylic sealer (in our craft supplies collection) for protection. Browse air-dry clay, polymer clay, and our full plaster of paris for casting work.

Frequently asked questions

What's the easiest clay for kids?

Air-dry clay. No oven, no kiln, no sharp tools needed. Mont Marte Air Hardening Clay is non-toxic, smooth to work with, and dries to a finish that takes paint well.

Can you fire polymer clay in a real kiln?

No — polymer clay burns and releases fumes at kiln temperatures. Polymer is oven-bake only at 110°C.

Is air-dry clay waterproof?

No. Even sealed with acrylic varnish it's only water-resistant for brief contact. Don't use air-dry clay for pieces that will see constant water (vases that hold water, outdoor garden pieces in rain).

What's the difference between modelling clay and air-dry clay?

Confusingly, the terms overlap. 'Modelling clay' in NZ usually means either oil-based plasticine OR air-hardening clay depending on the brand. Read the label — if it says 'air-hardening' or 'self-hardening' it will set; if it says 'reusable' or 'oil-based' it won't.

How long does each clay last on the shelf?

Polymer clay: years if sealed. Air-dry clay: months if wrapped in damp cloth + plastic; days if exposed to air. Plasticine: indefinitely. Pottery clay: weeks if kept moist in a bin with damp rags.

Where can I buy clay in NZ?

At Handy Mandy. We ship the full Mont Marte range across air-dry, polymer, modelling tools and plaster NZ-wide from our Auckland warehouse, free shipping over $75 NZD.