This tutorial uses Pebeo Vitrea 160 products. Shapeways' Stainless Steel material was used for the models. This tutorial is only for our Stainless Steel material, other materials have different properties and do not withstand that much heat.
You may want to give a touch of color to your shiny new Stainless Steel print or maybe you would like to paint it completely to give a patina or an impression of a different kind of material. Regular glass enamel is baked under lots and lots of heat, but I have found a consumer-friendly alternative that simply requires a use of your oven. I used a cufflink to experiment.
Clean the surface with alcohol or soapy water and let dry. Clean a small paintbrush. Don't skip this step, dirty brushes ruin good paint jobs. Get some Q-tips on hand and a paper towel, just in case you need to clean up small messes. Do not shake the paint, mix it by stirring if you have to, shaking will create air bubbles on the painted part.
Load a small amount of the paint onto the brush and paint your part. I've used another approach: Loaded a nice full brush and then unloaded it onto the face of the cufflink (inside the walls). Then I used a Q-tip, while the paint was still wet, to clean the raised dots. Alternatively you could use a small syringe to 'flood' an area with paint.
I found that 45 minutes between coats (if you're building up more than one) works ok. But let it fully dry for 24 to 48 hours before baking.
Baking is done at 160°C (320°F) for 40 minutes. I am not sure how it works with metal vs. glass, but I followed their technique in placing the object in the oven and then turning it on. That way the paint and the object heat up gradually together.
Cooling is also gradual. Turn the oven off and open the door slightly so the heat escapes slowly, let it cool (or you will burn yourself), 15 minutes was enough in my case.
Here are some of the samples we tried it with.