Hybrid vases, cone 6 white glaze and glaze calc program
Hybrid Leaf Vases
I liked making these 2 vases – the bases were made from slabs of clay and the wheel thrown neck was added after the hand built portion of the vase had set up (not quite leather hard) enough to withstand having the neck addition. I also made a bisque texture plate using ginkgo leaves from the little tree I planted in my yard – though I haven’t used it yet. The white glaze is new for me – it’s from Mastering Cone 6 Glazes by Hesselberth and Roy, pg. 108 “Faux Majolica”. There’s a great interaction between the white and the aqua color glaze where they overlap that I really like.
In an effort to use and store a limited number of glazes and all the associated raw materials in my small garagio, I thought this white would be good as both a liner and I might like to try painting some stains on top in the future maiolica style. I decided to be conservative and only made a 5,000 gram batch just in case I didn’t like it, but I have to say, it fires terrifically!
In regards to glazes, I decided to bite the bullet today and purchased the Digital Fire Insight Glaze Calculator after testing several different programs, even a free glaze calc program. I’m all about free, unless it isn’t working for me and this one isn’t a terribly intuitive program – but that really applies to me only. Maybe now that I have the glaze calculation program, I can add my glaze recipe page to my website. I’ve been too lazy to format tables in word for my recipes and it would be really cool for others to see the analysis that accompanies each.
Square Bottom Mug – hand built from slabs of clay
I really like the way this mug turned out – round top, square bottom and the faux majolica MC6 glaze interacts nicely with this green one too! In an effort to move away from the templates that ceramicist, teacher and writer Annie Chrietzberg gave to everyone this past summer during a workshop I took here in Denver, I tweaked her template just a tad giving the mug a square base instead of a round one. The tweak was minimal, but effective.
Speaking of Annie – I wonder if her ears are ringing right now…I enjoyed spending a couple of hours with her yesterday in my studio. She’s warm, funny and very generous with her knowledge. Oh Earth to Annie…thanks for stopping by!
Meanwhile, yesterday was hectic and I didn’t get a chance to do all my daily Internet activities such as responding to blog comments, answering emails etc. In the am, I took my daughter to visit the Denver Center for International Studies, which is a 6th grade -12th grade public magnet school in Denver. Denver residents are lucky to have school choice – but we are also cursed because choosing a school is like applying to college. She will be starting middle school next year and we’ve narrowed our choices down to 4 including the one above, Denver School of the Arts, Morey Middle School which has a gifted magnet program, and one other neighborhood school.
My first choice for her is the international studies school – it’s so cool, they start studying a foreign language in 6th grade (French, Spanish, Italian, Chinese or Japanese) and they visit countries where their language is spoken starting in 9th grade. Her first choice is Denver School of the Arts – but they only accept 20% of applicants. Besides, does our family need more than one artist? DCIS accepts about 50%, Morey is an automatic in – and the other school is just an extra for decision making purposes. All 3 of these schools are urban & very diverse – and bonus upon bonus – they provide busing!
The downside to all of school choice is that applications are due by Dec. 12 for following year and include essays, interviews, teach recommendations, test scores – all for 6th grade! It’s a little overwhelming for both of us. I promised her that if she decides to go to DCIS, I’ll take classes in whatever foreign language she picks. Wouldn’t Japanese be cool? Of course I’d sign up to chaperon field trips whenever possible!
TGIF,
~Cynthia
Cone 6 Pink Glaze Tests September 25, 2008
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
Success! Pink and Violet ^6 Glaze Test Recipes Part 2
This is a continuation of my last post.
Mason Stains in ^6 Glazes
In my second round of testing, I was optimistic that I’d found the holy grail of base glaze recipes to achieve a pink ^6 glaze – but I was mentally prepared to open the kiln this morning and find nada. Imagine my surprise and delight, when I opened my kiln and found these gorgeous tiles! After loads of research and internet sleuthing, I happened upon this article by Tony Hanson that included a recipe for a base glaze good for chrome/tin colorants on the ceramic-materials.com on Sunday morning. I quickly made up 3 test batches of the base glaze and fired up my little test kiln yesteray with anticipation.
To be expected, color developed much better after using a higher percentage of colorant. I decided to try up to 12% stain this time just to compare with my tests a couple of days ago where I used up to 10% stain. Truth be told, 10% is plenty – but I wanted to see if it made any difference. It looks like color doesn’t start to really develop until tile 3 which would be 25% of the total amount of stain used (in this case, 25% of 12 = 3% of the total 100 gram recipe which results in a very pastel color). I’m guessing that when I test some blues & greens, I will need even less colorant since cobalt and copper are much stronger colorants. Also, I’m going to try redoing the pink glaze using chrome oxide and tin with the new base glaze. Yesterday, Annie generously forwarded another chrome/tin compatible recipe to try and my friend Mary Cay emailed me this morning reminding me about a recipe that she included in the materials from a glaze workshop I took with her last year. Thank you to both of you!
I also retested the chartreuse stain using the pink base glaze #4 (used with the pink and violet stains sucessfully) from Tony Hanson. I’m interested in have 1 or 2 base glazes so that I only have to buy minimal ingredients in bulk for future use. And, I had a thought… I plan on using a combination of 2 different glazes for my work. For example, glaze the exterior of a cup violet and the interior chartreuse. My thinking is that if violet is a chrome/tin glaze that can have no zinc, magnesium and needs calcium – then some funky stuff might happen where the violet and chartreuse glazes meet. But, not if they’re the same parent base glaze (or so goes my rational). I may be wrong and I plan on calling Mason Color later today to ask some questions.
There is a slight color difference between the 2 glazes. The one tested in the last post is more green, whereas the one with the pink base glaze #4 truly is more mustard yellow. If that’s what I’m going for, I could simply use rutile as the colorant at a lower cost than the mason stains. I suppose this is the whole point of testing; to see what can be learned and how to apply the knowledge effectively.
Thermal Expansion and Clay/Glaze Fit
I still need to find out a little bit more information too, before I mix up big batches of glaze. Kris left a comment on my last post about the thermal expansion of the clay body I use. If the clay body and the glaze’s thermal expansion don’t jive, crazing and a host of other issues could crop up down the road. Funny, thing is that I was just reading up on this last night in Mastering Cone 6 Glazes, Chapter 5 “Fitting Glazes to Your Clay Body”. I need to call Mile Hi Ceramics this morning when they open and find out what the thermal expansion is for the 2 clay bodies I generally use – Ash (^6 white stoneware) and Aspen (^6 porcelain). If the glaze is too big for the clay body, shivering results. If the clay is too big for the glaze, crazing results. Shivering is not cool – chunks of glassy glaze falling off the ware. Crazing (fine crackling) is sometimes desirable for some potters, but isn’t really a good attribute for functional ware that comes into contact with food.
Update: Neither of the people I spoke with at Mile Hi Ceramics know the thermal expansion of their clay bodies – I was told to call back when the owner is in. Boohoo. Am I over thinking this?
Using Underglazes to ^6
I did come upon some other interesting test tiles in my studio a few weeks ago while cleaning. These were tests that I had mis-fired last year involving Duncan Cover Coat Underglazes. I was doing these tests to provide my kid’s clay classes reference color chips. The kids always wanted to know what the various colors were going to look like when fired. My mishap was due to my Aim cone 10 test kiln over firing due to a couple of very careless mistakes. I put a small pyrometric cone 6 in the kiln sitter, loaded the kiln, turned it on, ramped up the heat on my predetermined schedule. My mistakes: I wasn’t around when it was supposed to turn off and when I opened the kiln in the morning I realized that the kiln had totally over fired because one of the shelves was touching the kiln sitter. I’m not quite sure what temperature the kiln reached – the pyrometric cone was totally melted and black (normally white after a succesful ^6 firing) and the kiln fires to cone 10. It’s a good possibility that these tests were fired to cone 8-10, depending on how long it took the pyrometric cone to melt allowing the sitter to turn the kiln off.
I used cone 6 porcelain test tiles and though they didn’t melt or even bloat, they all have a sheen to them like glaze in all the unglazed places. So, why am I telling you this? Because I found out that Duncan Cover Coats can be fired quite high and retain their colors. When I get around to photographing them, I’ll post those results. Underglazes would certainly be an option for me to use as a colorant under a clear glaze. I should redo these tests firing them to cone 6 and compare the results. I have everything from yellow, organge, red, violet, light and dark blues, green and black in my “failed” tests.
I originally wanted to toss these test tiles since I was angry at myself for my mistakes, but held onto them for some reason. There’s something to learn in both our successes and more often in our mistakes. Zen master is teaching me again 
So – I’ll post those tests later this week for you.
Meanwhile, I’ll be teaching a kid’s class at the Art Student’s League of Denver starting next Monday called, “Mixed Media Marionettes”. The class is now full and is for grades 3-5 but, lucky for me I will have an assistant to help. I will be spending part of my time this week making the proto-type and lesson plans for the class so I’m well prepared. I pulled my daughter’s wood marionette down from her bedroom ceiling ceiling the other day and am studying its construction so I can successfully recreate a working one next week with the kids. I’m also deliberately working fast since we only have 5 days to work on these. 3 with wet clay and the other 2 decorating, assembling and hopefully playing with them on the last day.
Whew… have a good day,
~Cynthia
Happy Independence Day!
Happy 4th to all my US readers! For my family, it’s an occasion to enjoy some good old fashioned family fun. We’re spending a quiet day together and will join our neighbors late this afternoon at our local neighborhood park where we’ll enjoy a picnic while listening to a concert band play patriotic favorites. After dark we have a good view from our grassy knoll in the park of the fireworks display organized by the Denver Country Club. That said, today is as good a day as any to wander off topic…
When I lived in Maine, gardening seemed easy – an abundance of rain and acidic soil allowed me to grow my garden favorites with minimal effort. Here in the arid west, gardening isn’t quite as easy. We have alkaline soil which means a lot of my east coast faves don’t grow here well past one season such as azaleas, rhododendrons and astilbes and we don’t get much in the way of precipitation.
We do get an abundance of sunshine which certainly helps, but lack of water is tricky. In fact, I think here in Denver, we’re going on about day 30 with no rain. The storm clouds swell every afternoon, but any precipitation evaporates before hitting the ground. These magnificent thunderhead clouds move towards the mid-west where they have received more than their fair share of rain. Being fairly environmentally conscious, I’ve decided to use plants that are rugged and that tolerate harsher conditions. I’ve xeriscaped our backyard and hell strip (that little section of ground between the road and sidewalk) in front of our home. Did you know that it’s illegal to capture rain water in Colorado? Apparently it is considered stealing by the folks who own the water rights in our arid lands.
My little veggie patch
So where am I going with this? Yesterday morning when I got back from my little jog in the park around 6am, it was nice and cool. I started doing a little weeding and before you know it I’m full fledged all out dividing, tending and rearranging my yard. It didn’t hurt that I’m on drugs and had the stamina and single mindedness to keep on going. They are prescription drugs lest you become alarmed, and are my dirty little secret – which I guess isn’t so secret now afterall.
Here’s the back story on the drugs…. I was diagnosed with hypo-thyroidism after having my daughter 10 years ago. The symptoms of an under active thyroid are decreased metabolic activity which results in weight gain, fatigue, depression, infertility, anemia and heart disease. These were my symptoms – weight gain, fatigue, infertility, anemia and high cholesterol. I’m fully medicated now with Synthroid and Cytomel which is a combination of T4 and T3 (thryroid hormone) replacements to make me feel well.
For the most part all is well except that I never managed to lose the 25 pounds that I gained after being diagnosed. I’ve tried severe calorie restricted diets: low carb, low sugar, vegetarian, grape fruit, cabbage soup, even ran and trained for 2 half marathons. Weight loss – nada zip. And, I might add to all this, that I’m not a good dieter – it’s no fun and sucks the fun right out of life. Now, I’m not aiming for super model thin – I just want to feel better and lower my cholesterol. Both my father and paternal grandmother died of heart attacks – my dad at age 44 (only 2 years older than I am now).
Every 6 months I go to one of the top endocrinologists in Denver for lab work to check all my levels. About a year ago, the nurse practioner suggested phentermine to help lose the weight. In between last year and this, I visited a nutritionist and kept on trying to lose the weight myself drug free to no avail. Now, I’m not a huge fan of drugs – especially since it’s humbling to know that I will be on prescription drugs for the rest of my life. Yes – I have one of those little day of the week pill cases to keep it all organized!
After stepping on the scale at my bi-annual appointment on Wednesday, I decided what the hell, give me the phentermine! OMG – this must be what speed feels like. I haven’t felt this energetic in years, not to mention I’m not hungry and am not really interested in food right now. Weird feeling. I am feeling some side effects, mainly I have a really dry mouth – though it’s making me drink more water * bonus here in arid Colorado. I hope this works in the weight loss department and I’ll keep you updated as time goes on. One note about phentermine, you have to have good blood pressure and not be pregnant and it might cause your arm to fall off (okay not true about the last bit).
Thanks for taking my tangent with me… backtracking to yesterday morning’s garden binge – I could have kept going and going. I felt terrific – I haven’t felt this good in years. Meanwhile, I think I pulled a muscle in one of my little toes and I got sun burned after spending 7 hours in the garden working in a tank top and shorts.
The photo above is my little veggie patch. It’s not much to brag about, but I have 2 tomato plants, a zucchini plant and lots of herbs. It saves me a lot of money in the summer and it really yoinks my chain to pay $4.00 for a little packet of fresh basil. As an added bonus, they’re organic since I don’t use any chemicals in my garden. See that dinky little bamboo stake and jute fence around the veggies? That actually keeps my 2 big dogs out of the veggies.
Egyptian onions also known as tree or walking onions
I divided my Egyptian onions too. I originally planted them in my hell strip (see above) last year and they’ve gone wild. I thought that they were ornamentals, but it turns out that the little bulblets that grow on the top are edible. Next time my recipe calls for onions, I’m going to give them a try. They are purportedly stronger than regular onions.
Well, if this wasn’t a TMI post, I’ll be a monkey’s aunt! But, just maybe someone out in blogland will benefit if they stumble upon my site.
I’m off to the guild to mix some glazes after spending some quality time with Hopper, Roy and Hesselberth the past couple of days before heading to the park for today’s 4th of July festivities.
Have a great weekend,
~Cynthia
