PC- 11 Blue Spark
Blue Spark is a specialty glaze that can give dramatic metallic crystalline results when used correctly. Below find suggestions for the best results.
HOW IT WORKS:
Blue Spark is a glossy, royal blue glaze which develops small triangular dark gray metallic crystals that make this glaze look like lapis lazuli. This opaque glaze does not break over texture. For best results apply three even brush coats.
LET'S FIGURE OUT WHAT'S WRONG.
STILL NOT GETTING ACCURATE RESULTS? LET'S TALK BISQUE
Thickness of application can affect the appearance of the metallic glaze. If the glaze is translucent or dark with no crystal growth it may be too thin.
#2 BISQUE TEMPERATURE
The temperature to which your ware was bisqued can have an affect on the final piece. We recommend a bisque between cone 08 and cone 03, though a bisque as low as cone 010 will work.
LETS TALK CLAY BODIES
#3 CLAY BODY
The metallics do best on a clay body that isn’t fully vitrified in the glaze firing. Clay body color doesn’t seem to make a difference.
LETS EVALUATE FIRING TEMPS
#4 FIRING TEMPERATURE
The metallics do best at cone 6 but should be lovely even at cone 5.
STILL NOT RIGHT? TRY A DIFFERENT FIRING SCHEDULE.
#5 FIRING SCHEDULE
Most of our firings are done on a medium speed with no hold and no slow cooling schedule. We tested two alternate firings and found they reduced blistering in problem combinations.
Alternate Firing 1: long hold
Using the regular cone fire program (medium speed) we programmed a cone 5 firing with a 20-minute hold, giving a cone 6 (cone 6 was bent to 3 o'clock).
Alternate Firing 2: slow ramp/hold with drop hold
Popularized by Camille Hoffman, this program was created by Skutt to reduce pinholing and blisters.