October 09, 2020

Not Just Paint: Why You Should Prime Air Dry Clay Sculptures

Not Just Paint: Why You Should Prime Air Dry Clay Sculptures

Creating air dry clay sculpture calls for you to be a bit of a mad scientist: you experiment wildly with various media while using long-standing artist techniques to make truly fine art pieces. One thing I found is that if you're intending to paint your air dry clay sculpture, like any good artist, you need to prepare your substrate.

If you've done any kind of DIY-ing, you're likely familiar with prepping a surface. Priming is not just about sealing the material, but also creating a stable exterior for your paint. In this case, your substrate is clay and it should be primed (ideally) with gesso.

 Air dry clay sculpture painting
Tinted gesso primed sculptures above and then painted below

Gesso me this

Gesso is made of a combination of materials that I won't bore you with here, mixed into an acrylic base. Unlike acrylic paint however, gesso creates a toothy surface that paint adheres to easily. It is traditionally white, but you can buy black or clear gesso. You can also tint it with a bit of acrylic paint. 

The advantages of gesso:

  • Relatively cheap - a tub/tube lasts a long time
  • Can be thinned with water (in moderation) to preserve details
  • Weather or temperature are not an issue
  • Can mostly be removed if you mess up, and is generally forgiving


The Other Primers

Yes officer, I confess, I've used enamel-type spray primers from the hardware store. Guilty, as charged. They are easy to find and come in other colours, like brown. If you're making sculptures for your own pleasure, go for it. I switched to gesso due to the fact that it is an artist material and will not degrade overtime (plus, spray painting is a b***h).

House paint latex

Some other disadvantages of spray primers not dedicated to art purposes include:

  • Can be adversely affected by temperature or weather fluctuations
  • Big learning curve to apply in thin layers and cannot easily be fixed once on (e.g. drips)
  • The cans don't last very long, which ends up being pricier than gesso

Another one I have considered is house paint. It sounds like a good idea, especially since most of us have at least a couple of half-used cans kicking around. Sadly, the life expectancy of emulsion paint (often called latex paint in North America) is not great. Have you ever noticed that painted walls have a tendency to peel or slough off as a few years? Have you ever washed a painted wall and some paint invariably ends up on your sponge?

Even modern, high-quality wall paint applied with proper surface decoration can last maybe, what, 10 years? Humidity affects it a lot and whites yellow over time. Not ideal for artwork. You don't want to put all your hard work into a sculpture only to have it degrade after a short time.


Why Prime Air Dry Clay?

1. Uniformity: Air dry clays like Creative Paperclay (CPC) are water-based. Unlike epoxy clay or cold porcelain, the surface of CPC is porous. When you lay down the first layer of paint onto CPC, it soaks it up like a sponge and gesso will help you apply paint in a more uniform way.

Additionally, if you're using mixed media on your sculpture, for example your horse mane is made of a different material than the body, then priming will help to unify those elements before adding paint. It creates a more cohesive piece.

2. Sealing: Gesso creates a moisture barrier between clay and paint, and also clay and the outside world. CPC is water-based, and while it won't re-hydrate, it can be sensitive to humidity.  

Sealing the surface is also very important if you use lots of water heavy paints (like watercolour) so they don't affect the air dry clay sculpture itself. Plan on using oil paint? Remember that oil is corrosive, and you should lay down at least 3 layers of gesso to create a thick enough barrier.

3. Adhesion: Not only does it seal, gesso also helps the paints to stick to the surface better. Due to it's tooth (slight texture), gesso makes it easier for paints to stay on the surface. Funnily enough, if your surface is too smooth, the paint will not adhere very well as it has nothing to "stick to", and runs the risk of peeling off much easier. This is especially important on very smooth clay bodies, like epoxy clay

4. Strength: This last one should not be underestimated. Gesso is a like a layer of slightly flexible material over top of your work, and it can provide a tiny bit more reinforcement. Unless you're sculpting in bronze or stone, sculptures are fragile items, so I take any extra bit of strength where I can get it.


On Priming Ceramics

While paint will never be as resilient as a glaze on a ceramic sculpture, gesso-ing before you paint will help your cold finish*  last as long as possible for all the reasons listed above.

*The term to describe adding paint and other decorations to already fired ceramics that will not be put in the kiln again.

Prime gesso air dry clay horse sculpture
Use gesso to unify mixed media elements

Prime Time

While a painter easily layers gesso on a flat surface, sculptors have the added challenge of curves and edges. For those of us who hate to brush a 3D surface, you can purchase spray gesso. I have used spray gesso with success, however, due to my current studio set-up, painting it on is more accessible. Also, you will likely need to touch up nooks and crannies with a brush afterward.

My gesso application onto air dry clay sculpture is pretty simple:

More often than not, I brush on 2 light coats of gesso because I like to keep some of my sculptural texture. I let the gesso cure at least an hour between coats to ensure the adhesion is maximized and I don't pull off any semi-dry layers.

Before I start the real painting, I let the gesso cure for at least 24 hours. This is because I often use very watery surface decoration, and I want to ensure the surface is ready to handle everything I'm going to throw at it.

If you would like a smooth surface, you can sand the gesso in between coats (must be totally dry!). If you do this make sure you use a very fine sandpaper. I suggest 220 grit on the first/second pass, and then move up to 400 on the later layers for super smoothness. Wipe down after sanding to get rid of dust. This method requires at least 3 layers and often more, but if smoothness is your aim, this produces great results. 

Note: Gesso is quite thin (consistency of a runny yogurt), so ensure the surface of your sculpture is as smooth as possible before you prime to save on layers of gesso and time sanding.


Priming is just one of the many steps you should take in constructing an air dry clay sculpture that bring pleasure for many years. Don't be afraid to embrace your inner mad scientist and bring some tried and true artistic methods to sculpting with air dry clay. You might be surprised how well they work! 


What's Next?

What is Creative Paperclay?

Learn about sculpting thin areas with mixed media