Making Colored Slip

[Dave K]

I want to make colored slip for decorating. Is it as simple as adding stain to slip? Is anything else needed?  My slip is made from throwing scrapes.

 

I am attempting to make terra sig. Would coloring it be the same?

[Dick White]

You can make slip from throwing scraps. Some issues:

 

You will want the slip to be smooth, so you will need to push it through a fine sieve to both break down any lumps of clay and to remove any gritty grog. Sieving to remove the grog is best done when the slip is very wet, so then you need to dry it some and sieve it again to smooth out the lumps.

 

Adding colorants to wet slip is not very precise because you don't know the exact amount of clay in the slip so you can't determine an amount that is the right percentage of colorant. If you are not particular about the exact hue, you can just add some stain and fire a sample. You will need to glaze fire under your intended glaze it to see the exact effect. What you see in the wet bucket and what you see after the bisque firing are not representative of the final result.

 

As for coloring terra sig, I have found that the usual colorants (oxides, stains) have a particle size larger than the t.s., so the grains of colorant tend to scratch and ruin the t.s. surface as I buff it. Others have reported that this can be alleviated by ball milling the t.s., but I don't have a ball mill.

[Marcia Selsor]

Terra sig is made by separating the heavier particles from the finer ones.i would recommend going through the process, take the finer parts of the slip and the add the stain. Be sure to use deflocculent in the settling and again if the stain settles. Natural oxides can be a problem as mentioned above

Marcia

[Dave K]

Thank you for the replies, they were helpful.

[Chris Campbell]

 

Adding colorants to wet slip is not very precise because you don't know the exact amount of clay in the slip so you can't determine an amount that is the right percentage of colorant. If you are not particular about the exact hue, you can just add some stain and fire a sample. You will need to glaze fire under your intended glaze it to see the exact effect. What you see in the wet bucket and what you see after the bisque firing are not representative of the final result.

 

Instead of using scrap you could use a predetermined amount of clay? Then you could be correct about the quantities? Correct me if I am wrong but you could break up a measured amount of clay into water to make slip. 

 

 

You could do that but would have to dry out the wet clay before you made slip from it ... unless you are using a blender, then you can toss wet clay right into water.

You can also weigh your dry scraps before you use them if you want accuracy.