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I am trying to develop and expanded palette for foil saggars. So I am testing my 8  strongest colors and overlapping them, adding some washes of things like strontium chloride, calcium chloride,and magnesium chloride. I am particularly interested to see if the magnesium will have and influence on the cobalt sulphate or cobalt chloride. I made three of each test tile to fire at three temperatures at 100 degree intervals.  I am mixing in very small quantities of 6.5 grams per 1/8 cup of water. I have my kiln set up and covered up on the concrete patio and I'm waiting for the rain to stop.

 

Hopefully tomorrow will really be sunny. I have 17 tiles

 

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RonSa, Joseph F and glazenerd like this

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Here are the results fro my color tests. Chemicals were Copper, Cobalt, Iron, Manganese, chrome in the form of sulphates, chlorides and nitrates plus sodium and potassium nitrates. Minuscule amounts of 6.5 grams were mixed in a 1/8 cup of water. 5 various rows with three tiles with the same colorants fired at roughly 1175 F, 1250 F and 1350 F.

The tiles are marked roughly. Three circles of cases were Barium, Calcium and Magnesium chloride. Hoped to see if these fluxes would effect the metallic colorants as they do in a glaze. calcium seemed to do that the most.
a cross of copper nitrate was across the tile. Edited notations:
DISCOVERIES:
temperature variations were significant on Nickel and Cobalt Chloride and Copper Sulphate
Halos develops between nitrates and chlorides. Blushes worked well between Chlorides and sulphates 
White dots were from epsom salts and more colorful lighter dots were strontium chloride crystals
Yellow developed w/ Calcium Chloride and Sodium Dichromate
nice aqua blush w/ sodium dichromate , Copper Nitrate and Cobalt Chloride
Cobalt, Copper and Nickel chloride need higher saturation
Color in chlorides weakened in higher temperatures.
 

 

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I never used sodium dichromate before. I like the color response also. There is a lot of potential there. I will probably do a firing next week. Leaving for the Brickyard Bash this weekend at the Archie Bray Foundation and the Montana Studio tour in Helena. Potters fix this weekend.Beautiful weather here in Montana.

 

Marcia

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i know you are interested in the individual test tiles but what it looks like all together is a quilt.  if you had made holes in the discs, you could hang them all on the wall or door of your studio.

Judith B and Marcia Selsor like this

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Thanks Alice. I got the same responses from several people on Facebook sites.I am excited about the potential color especially with the washes which have reactive qualities as Glazenerd pointed out. Barium Chloride, Calcium Chloride and Magnesium Chloride. I am still seeking the Cobalt pink.

Marcia

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This is very useful information.  Thanks for sharing, Marcia.

 

What colorants were used on your "best test for the day" piece?  Are the outlines a halo effect?  Can you share the temperature and hold used?

 

In a previous post you mentioned the Riggs' saggar firing schedule of 1650F with a 20 minute hold.  Why go so high when such good coloration is achievable at lower temps?

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Jpdes,

The coloranst were sodium dichromate ***toxic, calcium chloride, and cobalt cl

Gloried firedto 1300 F held fir 5 minutes in aluminum foil sagger. The Riggs fire ceramic saggar she which are using combustibles in the saggars which need a higher temperature to burn off compared to fuming salts in aluminum foil. Also the foil breaks down around 1400F. Yes it is a halo effect.

Marcia

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