My goal was to learn what I could use to paint baked polymer clay without having problems. To me, that means a product with a nice consistency, opacity and resistance to scratching. Those with a green square in the chart above didn’t scratch off. I’ve included notes about their opacity and finish later in this post.
I separated the products into air-dry and heat-dry products. I decided not to test the fabric paints and silk screen inks that failed in my previous test on raw clay.
I applied each product multiple times with a nitrile-gloved fingertip onto baked sheets of polymer clay.
I let the air-dry products dry for 24 hours before trying to scratch them off with my fingernail. When almost all of them scratched off, I realized they needed to be baked.
I baked them for 10 minutes at 250˚, let them cool, then tried the scratch test again.
Still too many scratched off, so I baked them yet again for 10 minutes at 300˚. This gave better results. A strange thing is that three that previously adhered well to Soufflé, scratched off when baked at 300˚.
I cured the heat-dry products with a heat gun. I’ve found this works well because it doesn’t cause the clay to yellow as it might if you put it in the oven at too high of a temperature. For example, curing Kato Liquid Polyclay at 300˚ on Fimo clay, which cures at 265˚, would result in orangish clay.
For the heat-dry products, I first applied Kato Liquid Polyclay that I’d tinted. In my previous test of liquid clays, I’d learned it needs 9 minutes at 300˚ to cure with an industrial heat gun held 6″ away. Next, I applied Translucent Liquid Sculpey that I tinted and cured it 4-5 minutes at 275˚. Last, I applied Genesis Heat-Set Oils and Fimo Liquid Gel that I tinted and cured them for 1-2 minutes at 265˚.
I’ve since read that Genesis Heat-Set Oils need 10-15 minutes in a 265˚ oven (or not to exceed 280˚) for 15 minutes for each 1/4 inch.
I’ve also read that Gilders Paste can be baked at 375° F with no discoloration or alteration to the colors or their placement.
Following is a list of the products in the order they were used. I added comments about opacity and surface finish after each below.
I considered an air-dry product “thin” if the clay showed through or streaked after 4-5 attempts to cover it. That doesn’t necessarily mean the product’s consistency is thin, because some are quite thick. It means polymer clay can have a slick surface. Soufflé generally had less streaking because it has a pebbled surface.
This is important because if a paint streaks, you have to apply more than one coat to get good coverage.
The heat-dry products all covered the clay quite well, except some pulled away from Kato. Liquid clay mixed with alcohol inks was somewhat translucent.
Products tested on the left hand sheets:
- Golden Acrylic Paint – opaque, glossy
- Artist’s Loft Acrylic Paint – thin, satin
- Liquitex Basics Acrylic Paint – thin, satin
- Pébéo Studio Acrylic Paint – thin, satin
- Liquitex Heavy Body Acrylic Paint – thin, satin
- Winsor & Newton Galeria Acrylic Paint – thin, satin
- Martha Stewart Glass Paint Opaque – thin, glossy
- Martha Stewart Metallic Craft Paint – thin, satin
- Apple Barrel Acrylic Paint (Matte) – opaque, matte
- Folk Art Multi-Surface Acrylic Paint – opaque, satin
- Lumière Metallic Acrylic Paint – thin, satin
- Viva Precious Metal Colour – opaque, very reflective
- Swellegant Metallic Acrylic Paint – thin, satin
- Inka Gold – thin, satin, reflective
- Gilders Paste Wax – opaque, matte
Products tested on the right hand sheets:
- Genesis Heat-Set Oils – opaque, matte
- Kato Liquid Polyclay + alcohol ink – translucent, glossy
- Kato Liquid Polyclay + Genesis H.S. Oils – opaque, matte
- Kato Liquid Polyclay + acrylic paint – a gummy mess
- Fimo Liquid Gel + alcohol ink – translucent, satin
- Fimo Liquid Gel + Genesis H.S. Oils – opaque, matte
- Fimo Liquid Gel + acrylic paint – a gummy mess
- Translucent Liquid Sculpey (TLS) + alcohol ink – translucent, matte
- TLS + Genesis H.S. Oils – opaque, matte
- TLS + acrylic paint – a gummy mess
I left numbers 4, 7 and 10 of the heat-dry products off of the results because mixing acrylic paint with liquid polymer clay makes a sticky wad. (See the right hand column in the photo below.) The longer the liquid clay/acrylic paint mixtures sat, the worse they got.
Alcohol inks mixed with liquid clay was a bit runny. Genesis Heat Set Oils mixed with liquid clay was creamy.
Some products scratched off very easily. Others were harder. If they scratched off even a little, they didn’t get a green square in the chart at the top.
The most receptive clays were Fimo and Cernit. The other brands may do better if leached.
The only product tested that adhered to all clays was Kato Liquid Polyclay mixed with Genesis Heat-Set Oils. It was opaque, creamy and cured with a matte finish.
Viva Precious Metal Colour and Martha Stewart Metallic Craft Paint also did very well. Of course, you don’t always want metallic color. Many brands of non-metallic products worked well on certain clays, if heat cured.
I learned that most acrylic paint on baked polymer clay needs to be heat cured. Alcohol inks stain the clay. Gilders Paste seemed to stain the clay the more it was baked. If it were baked longer, I wonder if it would really meld into the clay.
The products that scratched off might be able to be sealed with a thin coat of liquid clay or other sealer. I haven’t tested this.
PHOTOS OF TEST RESULTS
On the left hand sheets in the photos below, the top scratch test is without baking. The middle scratch test is after the first baking. The bottom scratch test is after the second baking.
On the sheets on the right, I only did one scratch test.
If there are no scratches, the product adhered very well to the baked clay.
Please ignore numbers 4, 7 and 10. I shouldn’t have used liquid clay mixed with acrylics. It was a disaster.
Some of the clay sheets on the left shifted color because I put them in the oven at 300˚.
Kato wasn’t very receptive to the products tested. Numbers 2, 4, 5 and 8 on the right retracted from the clay. When heated, number 5 shrunk to less than half its original size.
In numbers 2 and 8 on the right, where the tinted liquid clay was scratched away, you can see it stained the clay.
The best product for painting Kato seems to be any brand of liquid clay mixed with Genesis Heat-Set Oils.
Premo wasn’t very receptive to the products tested either. The best products for painting Premo seem to be Golden Acrylics baked 10 minutes at 300˚, liquid clay tinted with alcohol inks or Viva Precious Metal Colour for metallics. Three other products tested work, too.
Cernit was one of the most receptive clays to the products tested. Almost every product tested adhered well after heat curing.
After heat curing, Pardo was moderately receptive to the products tested.
Fimo was the most receptive clay to the products tested. Almost every product tested adhered well after heat curing.
After heat curing, Soufflé was moderately receptive to the products tested.
Contrary to the other clays, numbers 7, 8 and 10 on the left (which adhered well when air-dried or baked at 250˚) scratched off of Soufflé when baked at 300˚.
Some products scratched off very easily. Others were harder.
The most receptive clays were Fimo and Cernit.
Most acrylic paint on baked polymer clay needs to be heat cured. Please see the chart at the top for individual results.
P.S. I bought all these products myself and received nothing from the manufacturers.
UPDATES: I just read that you can bake Gilders Paste at up to 400˚F. Baking it makes the wax disappear and leaves just the pigment. Since Inka Gold contains beeswax, the same may apply. Also, Inka Gold can be buffed.
Also, Gillian Wiseman says she uses Genesis Heat-Set Oils on Kato clay all the time and curing it for at least 15 minutes at about 305˚ makes it impossible to scratch off.
Allowing acrylic paint to dry a few days or longer, may make it less likely to scratch off.
With Swellegant, waiting for several days before applying the sealer, then baking 15-30 mins at 265˚ or 275˚may solve the issue of it scratching off. I plan to try this. I hope it works, as I really like Swellegant.