Types of Modeling Clays Explained

Figures made with air-dry clay (paperclay) by Tine Kamerbeek 

There are a few different types of clays popular with today's hobbyist that don't require a kiln or any special equipment.  The 3 basic types are oil-based, wax-based and water-based.*   We can also categorize them as heat-cured, self-hardening, air-dry or non-hardening.

*Note: There are also ceramic and stone-based clays, but these usually require a kiln to be cured and aren't included in our discussion.

The most popular heat-cured clays are the polymer clays.   Polymer clays are oil-based and must be heated to cure, however, a home oven can be used and a kiln is not required.   Polymer clays are available in many brands and many colors.  Most are very stiff when first removed from package and must be kneaded before using.   Polymer clay will be plastic like, waterproof and very durable if cured properly. 

Wallace and Gromit
are made of plasticine
on metal armatures

Wax-based clays are the plasticine clays. This type of clay stays flexible and never hardens. If heated, it will melt.   Plasticine is what's generally referred to as "modeling clay". It's also known as "Plastilena", which is a brand name.   Plasticine is often used to create clay animations because the flexible clay allows the figure to be re-positioned over and over. Air-dry and polymer clays are sometimes used for non-moving body parts.

The air-dry clays are mostly water based formulas, both commercial brands and homemade clays (cold porcelain and papier mache).  Because the water content evaporates as it cures, projects created with air-dry clay will shrink a certain amount.  There are hundreds of brands all with different characteristics and the shrinkage rate varies.   The finer quality brands of air-dry-clay harden to a matte, smooth, durable finish but must be top-coated and sealed because air-dry clay is not waterproof (with a couple of exceptions).

The New Clay News is all about this last type of clay.   If it's no-bake, air-dry or self-hardening...we'll talk about it and search out artists and tutorials!   Many new brands and new formulas of air-dry clays have recently become available and this "new clay" is increasing in popularity every day.  There are also a few new polymer-based air-dry clays sometimes referred to as "resin clay".   Two-part epoxy clays are included because they are also self-hardening.

So, you can see there is a lot to learn about air-dry clays.  If you are used to working with polymer clay and want to try air-dry clay, it will take some practice and some experimenting before you find the one that's just right for you.  Air-dry clays are not all the same and which brand would work best for you depends a lot on what you want to make with it.   The best way to learn is to join our Air-Dry-Clay Yahoo Group, where we have many generous members willing to share their expertise and experience.

The clay artisans in the Air-Dry-Clay Yahoo Group use and discuss all the commercial brands of no-bake, air-dry, self-hardening clays plus homemade clay recipes such as cold porcelain and papier mache. This includes brands such as Creative Paperclay**, Delight, Makin's Clay, LaDoll, Hearty Clay, Deco ClayCraft, DAS Pronto, Apoxie Sculpt, Lyra, Artista, Angel, Aves, FormoFit, Darwi, Flumo, Lumina, Celluclay, Sculptamold, Cold Porcelain, Crayola Model Magic, Crayola Air Dry Clay, Sculpt It, Paverpol and many more brands.