Tuesday, July 19, 2011

cone 6 glaze tests

Got the tiny test kiln fired Sunday. These tests were mainly glazes that Steven Hill is currently using for his cone 6 oxidation, and some that he used for his cone 8-10 firings, as well as a few of my own re-vamped version of a couple, and two new glazes of mine. Before continuing with this cone 6 ox spraying project, I wanted to see just what these glazes looked like on the various cone 6 bodies available from Highwater. I tested each glaze on at least 3 bodies - Little Loafers Glory, Buncombe white, Desert Buff and one tile on a P5 tile that I had on hand.

It seems that Little Loafers Glory or P5 porcelain would be the best choice. So I'll have to get to Highwater to get some P5 porcelain this week. They'd been out of it for a few weeks last time I was there, so this time I'll call first, or just make up my own if they're out. The firing schedule I used was a slow one, soaking an hour at top temperature till a free standing cone 6 was touching, then cooled to 1700, and from there fired down 50 degrees F per hour to 1600, held for an hour at 1600 and let the kiln cool naturally. Looking at the results, some of these would benefit from a hair more heat or tweaking a couple of these recipes with a bit more flux.

Not all the tests I have on tiles, made it into the small kiln; but I'll wait till I get the next bisque done in my Skutt, which should be in a week, then do another glaze firings of these and other cone 6 ox tiles and pots after that. It was as much leg work manually firing that tiny kiln with all the holds, firing down, etc as firing a gas kiln, so the rest of these tests will have to wait to be fired in the larger Skutt programmable kiln. The results from such a tiny kiln don't warrant this much work. I was exhausted!

Today I'll finally get around to slipping and decorating some more cone 10 soda pots, which will enable me to top off and fire the bisque kiln in a few days. Carpet cleaners are arriving in an hour and Jim says he'll deal with them so I can get into the studio right after breakfast for a full days work. Dinner is simple - linguini with pesto, arugula and watermelon salad, already prepped, other than making a light vinaigrette which I'll do right after breakfast.


  1. What a great group of test tiles. Boy that's a long soak at top temperature, what is your top temperature and hHow long was the total firing in hours?

  2. Linda, top temperature was a large, freestanding, cone 6 touching. I fired pretty fast in the earlier stages, slowing d 1060 so so and sped up a bit till I got to around 1900 or so and then slowed it. The whole firing took 12 hrs.

    Since some of these glazes looked like they could use a bit more heat, and these large cones go down faster than small ones, next time I'll fire these cone 6 ox glazes to cone 7 starting.

  3. Thanks June, I've been finding it interesting how changing the firing slightly really affects the glazes, initially I thought I should lengthen my top hold time, but then I shortened it by five minutes and slow cool to 1500 instead of 1400, I am learning each time.

  4. Linda, a really small test kiln is great for this, especially if you can bite the bullet and get one with digital controls. I have two small, tiny actually, cone 10 electric test kilns, which I have to fire manually. It's a chore to fire them that way if I want to do big holds and fire down; but it's either that or wait till I have enough pots to fill the larger Skutt.