Early this summer, I set out on a quest to expand my cone 6 glaze palette and since I’m attracted to vibrant colors, I decided to look for some candy colored hues such as pink, violet, and chartreuse.  I found success with Mason Stains as colorants in this pink base glaze #4 cone 6 glaze recipe I found on http://www.ceramic-materials.com.  After figuring out the cost per batch, I decided to try using chrome and tin oxide instead of Mason Stains to achieve a pink glaze and also to substitute some ingredients to make the cost per 10,000 gram batch less expensive.  My new criteria sent me off on another round of testing which I ended up abandoning to write some lesson plans in preparation for my teaching stints this last summer.

Cone 6 Pink chrome-tin combo

There is a slight error in this photo – there should be one more division of the glaze colorants lower right hand pile for the 6 part color progression glaze test.  In some ways, this glaze test was doomed to fail from the start because I lost the momentum of my glaze testing in July when I switched gears.

Cone 6 pink chrome tin combo ready to be fired

I don’t think I had anything to lose by proceeding with firing the test tiles even though I can’t say for certain which recipe I was using because it was not labeled – I could only make some assumptions based on my chicken scratch.  This test series also illustrates the need for taking good notes and accurate labeling in the studio.  The less than stellar results could also have something to do with the ingredients I substituted.  I still have another 2 batches of the base glaze to test, but since I’m not really 100% sure what these recipes are, I’m tempted to start over.  While I was in the heat of testing in July, I thought I would remember my reasoning and steps crystalline clear – big mistake.

Labeling my tests more accurately

So, in an attempt to be more organized in the studio – I added the date that I actually fired the tests on the reverse of each tile, along with the name of the (assumed) base glaze, numbered tiles 1-6 , clay body, temperature of clay – the latter three are scratched into the clay body before bisque firing and the former are written with a glaze pencil.

Cone 6 pink base chrome tin combo results

Results – blah.  I’m not sure if it’s the right recipe, the chemical make up of my substitutions or that my scale is off.  I had a dickens of a time measuring out .2 grams of chrome – it’s such a strong color.  After looking at the original recipe and then the “Raspberry” glaze recipe in Mastering Cone 6 Glazes, I know the proportion of chrome to tin was probably wrong.  .2 chrome – 7.5+ tin oxide would yield a decent result I think….

There is a little pink visible in the test tiles with higher amounts of tin and chrome

The latter 3 tiles are the only ones to show a hint of raspberry color – and these are the ones with the highest concentration of tin.  One interesting bit of info gleaned is that test tile #3 2nd photo up is close to the chartreuse color I’d like to use – much softer than what I achieved with Mason Stains.

Kiln is firing too hot

Another bit of information that I suspected, but have now confirmed is that two of my three of my kilns are firing hotter than cone 6.  Last time I visited Mile Hi Ceramics, I picked up some boxes of self supporting cone 5, 6 and 7 pyrometric cones.  Check out cone 7 – it’s touching the kiln shelf – the trio of cones should look like this instead.  These were placed in my test kiln which has a kiln sitter that turns off the kiln when it’s reached temp.  This past weekend I also tested my ancient Paragon – and it also over fired.  I haven’t tested my new digital Skutt 1027 yet, but will have the opportunity to do so next week sometime.  I almost have a full load to glaze.  Tips anyone?

Meanwhile, according to my studio log, I spent 12.5 hours out of my goal of 20 hours a week in the studio in the last 7 days.  I consider this a success considering that I was a substitute teacher 2 of those days and have reserved Sunday for family and getting ready for the following week.  This next week should prove more fruitful.

With that said, I’m signing off for the day,

~Cynthia