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
11 Responses to “Cone 6 Pink Glaze Tests September 25, 2008”
Sorry, the comment form is closed at this time.
Cynthia
My mind is a little fuzzy on this particular point, but i think i remember that in order for the chrome/tin to produce pink, you must use a base glaze that doesn’t have zinc as one of the ingredients. Zinc messes up the pinks.
Which intrigued me for there is another method of getting pink using barium and zinc with nickel. Emmanuel Cooper developed this and he’s pretty well known and respected in the field. (I’ve noticed a lot of other potters quote his recipe!) But it’s for Cone 10 and my kilns won’t achieve that temp. Did try to modify the base glaze to a Cone 5/6 but couldn’t get the pinks.
Let me know if you want Cooper’s pink. Will be glad to send it to you.
Hugs
Chae
The pink we have at my community studio uses tin oxide and rutile. Its a very pretty opaque satin/matte. I’d be happy to share it.
Have you searched http://www.potters.org for ‘pink 6′ ?
Recipes! I guess there is no pinch of this, smidgen of that in ceramics.
Cynthia,
OSIsemris, woeisl wie v;ismsedkt. But, soieru slis “soiciske didsl atlkek”. And, sile bidj-wiueres a;sj 45.
I can’t help myself! I’ve always wanted to do that when you get technical! I love reading it, but have no idea what exactly I am reading! Hope your exploration gets you something great!
hiya, my friend rose does a cone 6 pink/red depending on the glaze app. [yes zinc in the glaze does affect a lot of colours] I’ll ask her this wkd when we catch up for hahndorf artist market I’m sure she wont mind sharing…At our club we also have 2 exact same kilns that fire 30deg diff. at cone 6 we used to have a note attached to the pyro as a reminder but we’re all used to it now…just compensate your final firing temp by the discrepancy on pyro..
Hi Cynthia, my heart goes out to you with glaze recipes and experimentation. I’ve had so much bad luck with glazes lately, I am leaning towards a trend of natural looking pieces, perhaps with clear glazes, which in themselves can be a challenge as many of them react with the clay body and produce a blue clear, a grey clear or a bubbly clear. I will be experimenting with the clears in the next glaze load.
It’s weird that cone 7 is touching, but cone 6 still looks pretty perky. They look almost the same really. You’d expect 6 to be a little more melted given that 7 is touching. I think I’ve read that self-supporting cones show heat work a little differently than traditional cones. I’m not sure I understand about your manual kilns over firing. Is it just a matter of the cone or rod you are using in the sitter?
Chae – check and check – needs to be zinc and magnesium free, calcium rich. Part of my problem is that I picked up a test that is a little rusty memory wise. I did get pink with mason stains, but was trying for the chrome tin combo – which I should have done with the base glaze before trying to substitute ingredients – silly me.
Brian – I would be interested, thank you! Early this summer, I searched everywhere – I need to organize my notes and start fresh.
Janet – Alas, no smidges of anything. Have to put my lab coat on, pocket protector, and geek glasses on to get into glaze chemistry.
Jean – I love you! It probably looks Greek to non potters. My FIL sometimes reads my blog and he always tells me “You lose me on the cone this and the ox this…”.
Ang – I looked at the Orton site again and all their research and literature. I’m not sure it’s such a big deal if it’s off a tad. I did have one glaze (not mine, but the guild’s) that pin holed terribly this past summer. I don’t have a white glaze and took it to the guild to glaze and then fired at home. None of my glazes pinhole though. The orton website suggests putting in one cone lower if it’s over firing problematically. One of my glazes actually likes it hotter, so maybe not a big deal. I would love the recipe if your friend is willing to share.
Linda – Since I use white clay, I need color – lots of it. But, I love the toasty look of brown clays too. I just don’t use them anymore. Glaze testing is both fun and frustrating at the same time.
Deborah – Cone 6 is just slightly more melted at the tip, cone 5 is obviously melted and even stuck to the kiln shelf. Yes, it could just be a matter of using a lower temp cone in the kiln sitter. But, the thing that sort of tipped me off is that glaze firings are taking longer – which uses more energy if it’s not turning off until ^7+ when I only need ^6. Anyway, gotta walk my daughter to the bus stop right now….
Cynthia, your dedication to getting it worked out (and documenting it) is awe-inspiring. I get discouraged with lack of progress in my own studio and just want to skip on to something else. Hence, a lot of half-baked projects and ideas. I’m going to take a lesson from your experience and just keep keepin’ on to work out solutions. I’m seeing that it’s not “wasted” time, but part of the process. Thanks for sharing!
Oh my, all this makes my head spin. Uh, is this left brain stuff? I’m with your Father in-law. Too much thinking involved for me. *smile.
hey cynthia, yep it is a chrome and tin combo glaze that my friend rose uses, its prob got more to do with the base glaze and application for colour response and i forgot to get it last night so i’ll send her a mess. today she’s happy to share with you…