I plunked the recipe into Insight and played around with increasing and decreasing the ingredients just in case you made an error in the weighing out like you mentioned was the possibility. If you had put only 10 silica in and 30 spodumene then the Si:Al ratio goes from 8.57 to 6.38 which along with the slow cool could be enough to make a matte glaze. Also, if the error was with the OM4 ball clay the the Si:Al ratio is 6.37 ( 10 silica, 30 ball)
Does it feel like an alumina matte, or a silky / buttery matte?
I would include a test tile with no colour additives as a baseline.
Also, do you need to slow cool if you are going for a gloss?
- Stephen likes this