Wednesday, June 3, 2015

Test Run

I did my first glaze load in my new little kiln using their suggested slow program to cone 6 then added a slow cool to 1400 after a five minute hold at top temp. It fired to a full cone 7 so will work at developing my own program now that I can make a good guess at actually temperatures. A nice plus with my new little kiln is with two thermocouples I expect the kiln should be firing pretty evenly.
 Besides testing the glaze program I also did some glaze tsting. I was looking for a satin or metallic black to use on this bell. Rather than start from scratch I looked for something that already looked close. I found one but it's only colorant was some copper carb. Although it had some zinc in the recipe I wondered if the carb was actually oxide or if it was missing something like cobalt or manganese. So I added 10% RIO to half the test mixture and put it on my bell. 
Turns out the original recipe was not misprinted and did produce a black but I'm glad I added the RIO as it gave exactly what I was hoping for. The original recipe test below. 

 Another test was for a purple. Although I like it, it is a semimatte so I would want to test it well before using it functional work. It has a silica/alumina ratio of almot 9 so I was expecting a glossy glaze although it does have some magnesium in it. I think I'd like to use it on a totem that I'll make as part of our class project next year. The first test in on my clay, Mike's Stoneware from Axner and the second is on one of our studio clays, Buff from Highwater. They are actually closer than the photo shows.

One other glaze test was a very old one from my FAU days. It was one of my made from scratch recipes for an assignment. I found the old sample and dug out my recipe. It is actually a little glossy which surprized me as the original test was fast cooled and it was super dry. I like it a lot, however it is definitely not a glaze for functional ware as it has very little alumina. I think it will work well with the purple on my totem.
That same glaze is on the lower two thirds of the vessel next to the test, then Waterfall brown from the rim down halfway. I like how they worked together.
A good reminder about refiring: I put this beer tumbler in to refire hoping to seal over a couple pinholes that were bothering me. I added a little bit of glaze to the rim and that was it. However with the refire and the kiln going to cone 7 it sure ran! Reminds me of one of those drip candles from the 70's. Ideally I would only refire to cone 5 but I'm not a big fan of refiring to fix things so I rarely have much that I'd fill a kiln for cone 5.
Above is copper oxide. I usually stick to iron as I like its effect and it is safer than other oxides. However I really like the more orange color on this piece above. Just realized it came from the last load of my old kiln but my new little kiln gave me another cap jar below....

I'm headed to add some pine needles to another piece that came out of this load.
Hope you're having a great day!


  1. Lots of technical terms. Beautiful results.

    1. LOL Yes, I guess there are lots of glaze terms!

  2. Wow, there is sure a lot to know about glazes, temperature and time! It pays to know what to expect from your materials I guess.

    Fun results as always. Your pieces are very recognizable as yours! (In a good way-I always enjoy them!)

  3. Looks like your little kiln is working just fine. Looking forward to seeing what else comes out of it!


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