Sunday, August 15, 2010
Been getting my firing done in big bites, like a grasshopper does to a leaf. This Eastern Lubber Grasshopper, Romalea guttata, is almost 4 inches long and quite colorful. I thought about chocolate covered grasshoppers; when I saw the armor-like skin, I said to myself, no thanks.
The test fire for my new kiln was a fast 04 as recommended, completed in 7.5 hours, with one coat of kiln wash. It was rather smelly, the oils on the elements burning off. The cones showed the bottom shelf went beyond 04 target. If there's no clay pieces in the load does it fire hotter or cooler? I might get a few more cones like 03 and 05.5 if there is such a cone. Ideally I'd like to shoot for firing my bisque just tiny bit under 04.
I know if the kiln is fired faster it's programmed for a hotter fire from the factory. Perhaps a slow fire wouldn't be as hot. So I programmed in 05 for the bisque because I don't want to go over 04. I think higher than 04 will adversely affect glaze penetration and adhesion. I figure a little under is better than over 04 cone. I've adapted a firing log that Gay, from Sister Creek Pottery, sent me to keep notes about my firings. The notes will be invaluable as I go along, thanks Gay.
I had so many tall vases I had to use one side of the kiln for those. Remember the tall vase I wondered about, well it is too tall to fit in the kiln, unless I use a half inch post on the bottom. I'll check it out when I unload the kiln. I may have to take that one somewhere else to be fired. For a half shelf that's 26 inches across, I've used four posts, do you think I should only use three? If so that would give me more room.
I wanted to make a more even load, but I couldn't figure out any other way to load this one. Let's see, I've got 17 vases, 6 lided boxes, 4 pinch bowls, 2 fern trays, a magic umbrella (ha) covered dish, and a wall vase in this load. I really packed those vases, are they too close? I probably could have squeezed lots of small items on the right side of the kiln, but I didn't have any made. I'll have to remedy that for the future. I'm half an inch from the top on the right hand side, hope that's not too close.
I didn't get any of my plates or platters in this load, I figured if I got all the vases out of the way, then I could do a load of smaller pieces and plates. Actually I have a few more vases and some odd shaped sculptures for another load too. I probably could have put a shelf on the bottom right below the vases for plates, but I don't want plates on the bottom, so I left a bit of room at the top on that side.
Various circumstances beyond my control prevented me from firing my new kiln much till recently, so now I am getting caught up. My plans are for back to back firings for the next week or so. The bisque load was fired yesterday and is almost cool enough to open, firing was 11.57 hours, final temp 1881. Please check back for results, only the cones know for sure. I'll be doing a glaze fire in a jiffy. Comments and suggestions are welcome.