I am trying to create fairly large cinnamon-brown specks in a cone 05 cream glaze. While I know of materials to make dark brown or black specks in cone 5-6 glaze, I do not know how to make a lighter color (large) speck in low-fire glaze.

Any insights about materials to use for this?

Many thanks!

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I don't know if this will help or not. I have a handout from college "Guide to use of colorants" it is for cone 10 so it might do you any good. Black = [cobalt 1-2 + Manganese 2-4 ]or [Cobalt 1 + iron 8 + Manganese 3]:  Brown= [Rutile 5], [Chromium (with MgO, ZnO) 2-5]    [Iron 3-7]  [Manganese 5]  [Nickel (with Zn) 2-4] I  have no insights but this may give you some more possibilitys.  Good luck and happy firing

Hi Nancy. I do not know if this will work or not. What you want is large  brown spots in your glaze. In a higher temperature you can add  I think it is "Ilmenite". It does not dissolve in the wet glaze but melts out when it is fires. You need something that will do the same thing at ^05 (1880F, 1030C). I thought  maybe you could make a frit of sorts. Fire your clay body with the color you want in a crucible until it melts and reaches a temperature of 1800F, cool it, pulverize it to a certain mesh and add it to your glaze. It would be like a colored grog that would melt at maturing temperature and release the colorants fused to the clay body. Might add, I am not a chemist so I may be wrong,but it sounds like it should work. I will talk to a chemist where I work and see if he will help me try it. In the mean time you might try this. I went to [about.com Jewelry] How to make fused glass frit. Sounds easy. Get the color glass you want and add that to your glaze. The glass would not dissolve but it would melt out at ^05  It might make neet specks or it might make a big mess.  I am going to try it ^6 &^10. Test first. Happy Firing

Your ideas about using colored glass and colored grog are TRULY inspired! I will try both very shortly.

Thank you for your clever and thoughtful insights!

Initial testing of the frit idea shows it has a LOT of promise.

I had some frit on hand in other colors (used for fused glass work, COE 90 Bullseye product).  I tried green glass powder and chunkier orange frit.  Both melted well into glaze, although the chunkier stuff retained some dimensional feel and look.  The powder was sprinkled onto a damp glaze, and then some was glazed over with a clear.  The clear overcoat allowed the powder to lose its dimensionality but not its color.

Some colors will change with firing. Orange turned red. The green did not change color.

Powder frit creates very small specks, so I will have to do some trial and error to get the right size frit for the larger specks I need, but I am well on my way.

For information, I usually buy my fused glass materials from Delphi glass company, due to their huge selection and Bullseye product selection. I always use COE 90, but at small frit sizes and small quantities it does not matter if the COE is 90, 96, or anything else.

Again, Kabe, thanks for your great suggestion.

Check out the amaco soft arrorya glaze line.......at cone 05 they are lichen-like, but the hotter you fire, they smooth out and create a beautiful leopard-like look... I've used a low fire yellow under the arroya soft black fired to cone 5.6 and 7 with beautiful results...let me know if this is within the realm of what youre looking for and i can send photos.

 

Louis

I love your idea! I will give it a try.

Large cinnamon-brown specks can be made with "glaze crystals", especially in low-fire glazes.

The largest manufacturer is http://www.rabcospecks.com/

These same crystals, or similar products, are sold by Spectrum, Amaco and others at higher prices.



I really appreciate this lead to supplier I was not aware of.  Thank you very much!

Nancy

Norm Stuart said:

Large cinnamon-brown specks can be made with "glaze crystals", especially in low-fire glazes.

The largest manufacturer is http://www.rabcospecks.com/

These same crystals, or similar products, are sold by Spectrum, Amaco and others at higher prices.



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