GT Series (Toxic)

“GT Series”
These colors are leaded and not recommended for food surfaces.

  • Kiln needs to be well vented up to 900-1100 degrees.
  • If using a kiln that has had other things in it besides glass, such as copper-based glazes and materials it could affect the outcome of the colors.  They may turn grey or smoky looking.
  • Apply for even coverage.
  • Allow drying before firing.

What types of glass can I use with “G”, “BA”, “GS” “GO” and “GT’s” Series colors?
The colors can be used on most types of glass including:

  • COE 90
  • COE 96
  • Float (window) glass.
  • They also can be used as an overglaze on glazed ceramic pieces.  When planning to use with fired ceramic glaze surface, testing is recommended.


  • If the color is chalky or dull then it is probably underfired.
  • If color crawls or pulls away from outline then it is probably too heavy.
  • Some glass cleaners or not enough ventilation will leave a residue on the glass that can cause colors to be grey.