Mix this copper oxide with water or Glastac Glue and either paint or spray onto glass before firing.
Apply between glass layers. Less is more, so this pot will go a long way. Great value!
Once fired it will create wonderfully random blue bubbles. Experiment to get the look you want.
Generally, the copper oxide gets darker with density and if applied very thinly will give a lighter turquoise.
Looking for a lighter, more vibrant blue bubble? Try the Glassline Bronze Patina Bubble Pen.
The elephant in the second image was painted using copper oxide on French Vanilla glass, by one of our students during a Personalised Day with us.