Thickening enamel paint. Answered
I am looking for a way to thicken enamel paint to a buttery consistency similar to the acrylic paint you get in a tube. I worked out a decorative effect years ago which uses acrylics and is good for painting tins, but was never hard enough to last well.
The only thing I could think of was ground glass, but I'm not sure if you can buy this as a hobbyist, as it used to be used as a poison.
(If you're curious, the way I used to do it was to lay down a layer of acrylic in one colour, pick up the surface with a brush to make it stand out, wait for it to dry, then put a contrasting colour over it, and when it is dry sand it with wet sand paper until the colours from below stand out. It makes a marbled ripply effect which looks pretty e.g. in purple and orange).