Fix for scumming?

[carissman]

My well-aged red earthenware is now scumming. Post-mixing, is there anything that can be done about it or should I get rid of it? Thanks.

[hitchmss]

Barium is often used to prevent scumming in clay bodies. I dont have personal experience with this, so the %'s, or specific process for adding into your clay I am unsure of. I was going to write here about the health concerns using barium in the studio, and the potential for leaching in functional wares, but Tony Hansen did a much better job than I could, and it saves me from typing.

https://digitalfire.com/hazard/the+use+of+barium+in+clay+bodies

[carissman]

Thanks for the info. My clay is already mixed, and I wouldn’t mix in barium at this point. I have heard whispers of vinegar to counteract scumming. Does anyone know anything about that?

[PeterH]

On 2/12/2022 at 2:10 PM, hitchmss said:

Barium is often used to prevent scumming in clay bodies. I dont have personal experience with this, so the %'s, or specific process for adding into your clay I am unsure of. I was going to write here about the health concerns using barium in the studio, and the potential for leaching in functional wares, but Tony Hansen did a much better job than I could, and it saves me from typing.

https://digitalfire.com/hazard/the+use+of+barium+in+clay+bodies

There was an error in the label of one of Digitalfire's pictures, which has been corrected to state that the treated mug is on the left.

[Denice]

Does your scumming happen after the bisque or does it show up after the glaze firing.    I had this happen with some Laguna Red Calico,   I fixed it by cleaning my bisque with a micro fiber cloth instead of washing it with water before I glazed.    I didn't throw the clay away but decided it was trouble and didn't purchase anymore of it.    Denice