Air-dry clay or polymer clay modelling

How they harden, and it changes everything. Air-dry clay sets on its own over a day or two with no oven, but it shrinks, can crack, and is not waterproof. Polymer clay stays soft until you bake it at around 110-130°C, then cures rock hard and durable. Air-dry suits quick decorative pieces and kids. Polymer suits anything you want to last, paint precisely, or wear as jewellery.

It dried too fast or too unevenly. Thick pieces crack because the outside hardens while the inside is still wet and shrinking. Build over a foil or foam core to reduce solid mass, dry pieces slowly away from direct heat and sun, and turn them so all sides dry evenly. Small cracks can be filled with a slurry of the same clay mixed with water, then smoothed once dry.

Smooth as you go, not after. Keep your fingers and tools slightly damp (for air-dry) or use a tiny amount of hand lotion (for polymer) to blend seams while the clay is still soft. Once dry or baked, sand with fine sandpaper, working up through the grits, to remove remaining bumps. Trying to smooth a fully hardened piece by hand alone never works, so address the surface at the soft stage.

Usually yes for air-dry, optional for polymer. Air-dry clay is porous and not water-resistant, so a sealer (a few coats of matte or gloss varnish) protects painted surfaces and adds durability. Polymer clay does not need sealing, though a varnish can add shine or protect surface decoration. Acrylic paint works on both. Paint polymer after baking, never before, because some paints interfere with the curing.

Yes, if you start small and simple. A pinch pot, a small dish, or a few beads are achievable in a first session and genuinely useful. The mistake is attempting a detailed figure straight away and getting discouraged. Both clays reward repetition, and your third pot will be markedly better than your first. Begin with forms that hide imperfections rather than ones that expose every wobble.