Library: Melting Comparison Between Different Metal Oxide Colorants

These colorants were mixed 50:50 with Ferro frit 3134 (high boron, no alumina). The powder mix was melted in a crucible at cone 6.

-Red iron melts into a black slag with lots of entrained bubbles.

-Two brand names of iron chromate melt similarly to iron oxide, one is a little more fluid.

-Two varieties of black copper oxide have melted with clear evidence of boiling, the melts were so corrosive that they have actually dissolved the firebrick separator that was between and dissolved through the bottom corners of the crucible.

-Cobalt oxide has melted completely and during cooling has formed a network of needle-shaped crystals that permeature the entire matrix.

-Cobalt carboante has melted so actively that it has almost boiled over the edges of the crucible, it has also crystallized (but not as much as the oxide).

-Manganese dioxide has melted completely and frozen into a smooth metallic glass.

-Two varieties of ceramic rutile have melted enough to pull into a island in the center of the crucible. One contains a glassy component that has drained and is corroding the crucible.

-Chrome oxide has not melted at all, it has simply shrunk toward the center.

-Frit 3134: Melts completely from cone 06 upward.