Underglaze Bleeding Wanted!

[Bill Kielb]

@M5Pots Thicken the underglaze strategically along with a fluid clear gets some control in the bleeding areas. Have also achieved interesting similar looks by using underglaze over bisque, and misting with a very fine mist to get movement pre glaze application. A judicial spritz or two from a well controlled air gun also helps move things in custom ways while spraying past stencils also allows for some custom feathering especially with an airbrush.

Edited December 17, 2020 by Bill Kielb

[M5Pots]

On 12/17/2020 at 1:55 PM, Bill Kielb said:

@M5Pots Thicken the underglaze strategically along with a fluid clear gets some control in the bleeding areas. Have also achieved interesting similar looks by using underglaze over bisque, and misting with a very fine mist to get movement pre glaze application. A judicial spritz or two from a well controlled air gun also helps move things in custom ways while spraying past stencils also allows for some custom feathering especially with an airbrush.

Thank you, this sounds like it would do the trick! 

[M5Pots]

Also, what brand would have a fluid clear. Should it be one that says zinc free? 

 

[Bill Kielb]

12 minutes ago, M5Pots said:

Also, what brand would have a fluid clear. Should it be one that says zinc free? 

Zinc can affect some colors so folks generally want zinc free clear so as not to affect underglaze colors. A fluid glaze is one that melts and flows a bit. It can be achieved in a number of ways such as making the glaze melt a bit earlier with more flux and even if the glaze by composition has relatively low amounts of silica and alumina.

There is no magic predictor of when a glaze melts, it melts by composition so all glazes are really tested at or around their cone range for a good melt as well as how much they move when fired to a particular cone. It’s just a gravity and fired fluidity thing so there is no magic answer to give you. Experience is the best predictor and maybe some folks will offer up a favorite recipe.

When I want something to move more I will increase the boron slightly to get it to begin melting earlier, say cone 4 instead of cone 5  for example. But testing always is the final decider.

Edited December 19, 2020 by Bill Kielb

[M5Pots]

On 8/20/2019 at 11:44 AM, neilestrick said:

 I follow a number of people on Instagram who use bleeding underglaze, and I've never seen them making it bleed in the raw stage. It's always the glaze causing the bleed. I can control the degree of bleeding on my work by simply making the glaze more or less fluid.

Hi, 

How would you make your store bought clear glaze "more or less fluid"? Also, would you choose the clear without zinc? 

Thanks so much!

MM

[neilestrick]

1 hour ago, M5Pots said:

Hi, 

How would you make your store bought clear glaze "more or less fluid"? Also, would you choose the clear without zinc? 

Thanks so much!

MM

With a commercial glaze it's complicated because you don't know the formula of the gaze. So you can either fire it hotter, or add a little frit  to it. 1-2% frit 3134 may be enough to get it to bleed, but you'd have to estimate the amount of glaze material if you're working with a premixed wet glaze and do a lot of testing. By adding frit you'd be voiding any food safety labeling, so you'd need to test it for durability and safety. That little bit of frit shouldn't make much of a difference, though. To make it less fluid you could add equal parts EPK and silica.

Zinc free is always a good choice when working with colors.

[M5Pots]

1 hour ago, neilestrick said:

With a commercial glaze it's complicated because you don't know the formula of the gaze. So you can either fire it hotter, or add a little frit  to it. 1-2% frit 3134 may be enough to get it to bleed, but you'd have to estimate the amount of glaze material if you're working with a premixed wet glaze and do a lot of testing. By adding frit you'd be voiding any food safety labeling, so you'd need to test it for durability and safety. That little bit of frit shouldn't make much of a difference, though. To make it less fluid you could add equal parts EPK and silica.

Zinc free is always a good choice when working with colors.

Thank you for this. Very helpful!

[KimberlyM]

This is Dawn Candy doing the exact demo

https://ceramicartsnetwork.org/pottery-making-illustrated/pottery-making-illustrated-article/Anything-is-Possible#