Pigmented Glaze Issue!

[jesidiab]

Hi glaze friends!

 

I have been running into an issue when I try and create an ombre effect around the rim of my bowls. The bowl is first dunked in EM-1002 Alabaster White Glaze (Laguna Clay), and then the rims are airbrushed with a pigmented version of the Alabaster White Glaze using mason stains. My issue is seen in the attached images - it's as if the pigments collect in areas (as seen in the blue bowl) instead of evenly spraying for a seamless ombre. I've tried using an underglaze instead of a pigmented low fire glaze, and it results in a "cracking" look as you see in the pink bowl. 

 

The image with the purple mug is the look I am trying to achieve, and was a total fluke that I have had an impossible time trying to recreate. Does anyone have any advice on how I can create a seamless look? 

 

Thank you!!!!! Praying for a holiday miracle  

 

Jess 

 

 

[Min]

Hi and welcome. 

 

-When you combine 2 glazes (or an underglaze and a glaze) on a pot you have created a third glaze, the white base glaze, the coloured glaze and the third being the combination of the two where they are overlapped.

 

-So, with the lovely effect in the first 2 pictures, the blue glaze has something in it (the stain) that is interacting with the base glaze. The glazes are melting and flowing together more than just the base glaze alone. 

 

-With the pink pot, underglazes stay where you put them when applying directly on the clay (bisque or greenware), they are stiffer than glazes in most cases. You put them over the glaze right? When the glaze melted it moved a bit (as glazes do) and the stiffer underglaze didn't want to hence the "cracking" look to the glazed surface. 

 

-With the mug I'm guessing you used a different stain that didn't cause the fluxing the blue stain did resulting in a stiffer glaze that didn't flow like it did with the blue bowl but isn't as stiff as the pink underglaze.

 

-One last variable is the heatwork the pots got. Lots of glazes flow more when fired hotter than usual.

 

Kind of like Goldilocks of glazes, one is too fluid, one is too stiff and one is just right. Through trial and error, aka testing, you will need to match the quality of the stain to the glaze to get the effect you want.

[bciskepottery]

Rather than mix the stain/underglaze with the glaze and spraying over the base glaze, consider just spraying the underglaze/stain on the base.  That way you are not increasing the thickness of the glaze application.