Modelling clay air dry, air dry modeling clay and air drying modelling clay are the same product with the words in different orders and the spelling on either side of the Atlantic. What actually needs separating is this material from the non-hardening modelling clay most people met at school, because the two behave nothing alike.
Hardening and non-hardening are different materials
Non-hardening modelling clay, the plasticine kind, is oil based. It never dries, which is what makes it reusable and what makes it useless for anything you want to keep. Air drying modelling clay is water based and sets permanently as it loses water. If a product does not say it hardens, assume it does not, because the packaging almost always says so when it does.
Why the spellings differ, and why both are here
Modelling with two Ls is standard British usage and modeling with one is American, and both appear in real search volume in the UK because packaging, retailers and video tutorials come from both places. This site carries both rather than picking a side, in the same way it carries calipers and callipers, because a buyer types what they saw rather than what a style guide prefers.
What it is good at
Detail. A fine air drying modelling body takes fingerprints, tool marks and texture crisply and holds them, which is why it suits figures, ornaments and models rather than functional ware. It is also forgiving: it can be worked, left, dampened and worked again over several sessions, provided it is wrapped when you stop.
Keeping an open packet usable
The one maintenance job is stopping it drying in storage. Wrap the working piece and the unused clay in plastic, squeeze the air out and keep it somewhere cool. Clay that has stiffened can be brought back by wrapping it with a damp cloth overnight; clay that has gone completely hard can be broken up, soaked and reworked, though the texture is never quite as good.
Questions people ask about modelling clay air dry
Is modelling clay the same as air dry clay?
Not necessarily. Plasticine-type modelling clay never hardens; air drying modelling clay sets permanently. The packaging is the only reliable guide.
Modelling or modeling?
Both are used on products sold in the UK. Two Ls is British usage, one is American, and they name the same material.
How do I keep an opened pack from drying out?
Wrap it tightly in plastic with the air squeezed out and keep it cool. Stiff clay can be softened with a damp cloth overnight.