After reading this article you will know everything there is to know about painting and sealing your polymer clay while avoiding any paint chipping and scratching. I will also address the most common mistakes and problems that people run into and how to avoid all of them.
Polymer Clay can be easily painted but there are quite a few things, that you have to keep in mind. There is an official article from Sculpey, that is all about products, that can be used on polymer clay. You can read it by following this link here. The part about painting is relatively short, however, so I decided to write this article, which is much more in-depth and covers a lot of problems the article above doesn´t.
How to Paint Polymer Clay?
I personally always paint my polymer clay with acrylic paint.
Acrylic paint is easy to come by, comparably cheap and easy to work with.
The article from Sculpey states, that they heat up the clay before painting it but I never did that and I don´t feel like it is really necessary to do so.
I would also recommend to NOT paint the clay before baking it. Acrylic paint is water-based and if not all of the water has completely evaporated from the clay when you put it in the oven you might have nasty bubbles appearing on the surface of the clay or the clay might even not harden completely and you will end up with a very brittle clay.
So while it is entirely possible to paint the clay before baking it I would not recommend doing so!
So to paint polymer clay simply get your acrylic paint and apply it without thinning it down to your sculpture.
Make sure, that the sculpture is completely hardened and has completely cooled down before you apply any paint to it.
If the paint is not sticking properly or you have trouble with the paint covering up the clay underneath then you may have to prepare your sculpture before you can paint it.
If the paint is not adhering to the polymer clay properly then this may be because the surface of the clay has built up a thin oily film from baking which will repel water. And because the acrylic color is water-based it will also repel the acrylic color.
To get rid of this oily film simply use some rubbing alcohol and a piece of cloth. Put some of the rubbing alcohol on the piece of cloth and then go over the sculpture carefully rubbing away the thin film.
Wait until the alcohol has evaporated, this will only take a few seconds and then try to apply some acrylic paint to see if the film is gone and if the paint sticks.
If the paint doesn´t stick then just go over the sculpture again with some rubbing alcohol until the film is completely gone.
After you are done painting your project you will have to seal it or the paint may chip off.
I always like to either use an acrylic sealer or varnish.
Just apply the acrylic sealer after the paint has dried in a very thin layer and your colors will be water-resistant and scratch-resistant. No more chipping.
You can get acrylic sealer at every crafts store and you can find varnish in every store, that sells wood.
Varnish is normally used for sealing wood but you can also use it to seal your paint job. Simply apply the varnish in a thin layer with a paintbrush to your sculpt and leave it to dry for a few hours. Then it will be waterproof and scratch-resistant. Just make sure to get a varnish, that drys transparent and shiny.
If you want to read more about sealing your polymer clay then you can read this article, which I wrote, about properly Sealing Polymer Clay.
What Kind of Paint Do You Use on Polymer Clay?
The short answer is, any waterbased paint will be fine but acrylic paint is the easiest and best paint for polymer clay. If acrylic paint doesn´t stick to your polymer clay, then simply prepare the surface by rubbing it gently with rubbing alcohol. After Painting Seal your Project with Acrylic Sealer or the paint will chip off.
So generally, water-based colors are fine as long as they can cover the underlying color of the clay.
I highly recommend using acrylic paint. It is easy to use, drys quite fast and is easy to seal. Most crafters or artists have at least a few acrylic colors at home, so you don´t have to buy them, and they are non-toxic.
Don´t use any oil paints or base paints on polymer clay. While some of these colors may work just fine a lot of these types of paints will actually react with the clay over time and deform it slightly or just peel off.
As I said, it can work if you use these types of colors but may get unlucky and your paint job could ruin your sculpture. I personally just stick to acrylic paint.
Do You Paint Polymer Clay Before or After Baking?
The short answer is, you can do both but painting the polymer clay before baking it may cause some problems if not all of the water from the paint evaporated completely. The better and safer way is to paint the clay after baking when it is completely cooled down and hardened.
In the article from Sculpey, that I linked to at the beginning of this article, they also write, that it is possible to paint your clay before you bake it in the oven.
As I said, it is entirely possible to do but it is also not as easy to do as it may sound in their article.
The main problem, that you are going to have, is getting rid of any water, that might be inside the clay.
Acrylic paint is water-based paint and if you bake your clay with some leftover water in it then the clay will not harden properly and it will be brittle when you take it out of the oven or it can even form nasty bubbles on the surface of the clay.
So if you decide to paint your project before painting it, then give the water enough time to evaporate before you bake your clay.
My recommended way to paint polymer clay is to paint it after you baked it. Wait until the clay is completely cooled down and fully hardened before applying the paint.
This way is much safer and you don´t run the risk of damaging your sculpture.
You can also get a wide variety of colored clay, so consider using these before you color the clay yourself. You can read all about picking the right clay for your project in this article, that I wrote.
Can You Paint Polymer Clay With Nail Polish?
In short, yes you can paint polymer clay with nail polish but it is not recommended to do so. Nail polish will yellow when it is exposed to direct sunlight for too long and nail polish tends to get sticky when it comes into contact with water too much or when it is humid.
I would not use Nail Polish to paint polymer clay. In some cases, it might even work fine but depending on the brand of nail polish and how humid it is the nail polish could actually cause quite a lot of problems.
Nail polish is also quite expensive so it is actually cheaper to just buy acrylic paint and some acrylic sealer and you will have a much better and more reliable way to paint and seal your polymer clay project.
So even though it is possible to paint your clay with nail polish and you may even get a good result I would still not recommend it.