Why does turquoise fire out to be green?

[Leslieb]

My dipped PC 25 turquoise turned out a dark pea green when fired at cone 5. What went wrong? On a B mix bisque fired at 05.

[Pres]

Have you used this glaze before with successful results? Did this occur with one piece, or all of them? What was your firing schedule? Post a pic. Is the glaze from a bottle or did you order the dry glaze? Are you certain the glaze was mixed well?

Often with glazes that are mixed from powders some oxides will settle earlier than others requiring thorough mixing and at time sieving to make certain everything is reconstituted. I asked about the kiln because either hot spots or firing schedules can effect the glaze fired results. Often with a new commercial or home mixed glaze you will need to experiment to get the advertised result. Hope these help.

 

 

best,

Pres 

[Min]

Could very well be a glaze thickness issue. A quick look at the glaze from the Amaco site shows the difference thickness can make. Before glazing more pots I'ld take a scrap/test pot and do one dip all over then dip a second time for the top half of the pot and see if you get the rutile/turquoise colour is better. I'ld also measure the specific gravity of the glaze so you can replicate results. (lots of posts about measuring specific gravity if need it,  do a search on the main page)

Welcome to the forum.

 

 

[Bill Kielb]

2 hours ago, Leslieb said:

My dipped PC 25 turquoise turned out a dark pea green when fired at cone 5. What went wrong? On a B mix bisque fired at 05.

Aside from what has been mentioned peak temperature can have an effect on many glazes. Not sure if you fire with cones to confirm what they actually fired to, but all that’s been said, mixture, thickness, etc….  Including temperature can influence the final look as well. Post a picture if you can, interesting to see the finished product.