Adding Color To Glaze

[cracked pot]

I would like to add color to my Falls Creek Shino as discussed on Ceramics Arts Daily.  My question is, can I mix a large batch of dry glaze, mix it together well and then divide it out into 100 gm portions to add the colorants.  In other words, is it risky to divide up the batch before adding water?  Once mixed with water, I don't know how to divide it up and figure out the percentages of color to add.

 

[oldlady]

yes, you have described the exact steps you should take.  divide the very well mixed dry ingredients and color each division with a different color if you like.    

 

if you are feeling daring, there is no reason you need to make the batches  exactly 100 grams.  you are only testing for color, right?  smaller batches allow testing more varieties of color.

[cracked pot]

Thanks for the advise.  Looking forward to playing with the colors.

[neilestrick]

You just have to make sure that you mix the dry batch very well. You can actually go into the dry batch with a stick blender to help break up any clumps. Wear a mask.

[Callie Beller Diesel]

There is math that would let you figure out how much dry mix is in a wet glaze. You have to make sure you weigh your water as you put it in, but it's doable.

[cracked pot]

Thanks for your responses. I think I'll stick to the dry method, don't have a math brain. I'll let you know how it turns out.

[Marcia Selsor]

I mix 250 grams dry, then add it to water, sieve and divide it evenly into 5 plastic cups. Then I add the colorants to the cups.

1%= 0.5 grams etc. I make 15 mixes with these.

I use each one alone on the first test tiles.

 by taking a tsp of 1 with the other 2,3,4,5

The I mix 2 with the other 3,4,5

then 3 with 4, 5

and 4 and 5 

[cracked pot]

OK, here the results of my experiment with Falls Creek Shino. I mixed a large batch of glaze, mixed well, measured out 100 gm of dry mix into five cups. I added

2 gm of cobalt carbonate, 2 gm copper carbonate, 5 gm teal mason stain, 5 gm leaf green mason stain and 5 gm buttercup mason stain. The results are very dark and

the color does not show up unless you have strong light on the piece. I probably won't use these again but it was fun to try.

Just bought John Britt's book for cone 6 glazes and will be trying some other glazes to get the colors and surface I want.

 

I used pieces my grand daughters made to test because they had lots of texture. the one photo shows a bowl with the original glaze with a

small bowl inside with buttercup stain added.

 

Marcia, I may try your method next time, it seems simpler.

[oldlady]

there is one thing none of us mentioned and might have made a difference.   read britt's book and pay attention to whatever he says about a BASE glaze.  i think you had colorant in the mixture which influenced the results.  sorry, should have said so.

[High Bridge Pottery]

Looks too thin. How did you put the glaze on?

[cracked pot]

Thanks Old Lady(really hate calling you that) I am reading the book now.

 

High Bridge, I put the glaze on as I normally do, two 5 second dips or three good brushed layers. Still have lots left of the samples so will try it thicker next

time.

I made one critical error that I know of, I did not mix a cup of the base glaze alone for comparison. I will do that in the next firing to see if I messed up the

measuring in this batch. I always write out the formula and check off when each ingredient is added to the bucket but mistakes happen.

 

Thanks for the feedback.

[Venicemud]

I have made up a few test batches of this glaze, it can give very nice results but when thin it does give you a dark look. Also you are using a red clay that can be contributing to the darker appearance. Too thin a coat definitely tilts towards the dark side and you may have to try out higher percentages of the stains. One I made up with a Zinc Vanadium Blue required 15% stain. By the way, dark or not I think some of your results are very nice looking.

[Venicemud]

You inspired me to go back and look at the article by Deanna Ranlett, I couldn't remember whether I included the zircopax and tin oxide when trying out different stains. The answer is yes, Ms Ranlett speculated that the addition of these opacifiers helped the color "float" and that without them the results were not nearly so satisfying. Did you omit or include these in your tests?

[cracked pot]

In my recipe the Zircopax and Tin Oxide are always part of the mix.

Alberta Slip                                                 56

Gerstley Borate                                          19

NC4 or Soda Spar(I use Minspar 200)         9

Silica                                                             9

Lithium Carbonate                                        7

Zircopax                                                        9

Tin Oxide                                                      5

 

I use this all the time on the dark clay and it does need a heavy application.  I'll try more tests and see what happens.  I'm having a lot of fun with this!