Post #790611 by MadDogMike on Mon, Oct 22, 2018 7:45 PM

Thanks Wendy. Jon, you got PS skilz!!! :o

Here's the deal - I WANT a new $1000 kiln. I guess I could AFFORD a $1000 kiln. But I just cant JUSTIFY a $1000 kiln because ceramics is just a hobby for me :lol: My KilnSitter (that turns off the kiln when it's hot enough) isn't working so I have been using a pyrometer (thermometer). But the last few items I fired developed hundreds of little holes in the glaze. I suspected the bisque firing wasn't hot enough and didn't drive out all the gasses. Then when I glaze fired it continued to release gas causing the bubbles. So I tested my theory with some Orton cones.

I have been firing to 1800F for Cone 04. With 05, 04, and 03 cones, the middle cone (04) should have bent down and the tip touched the kiln floor. But at 1885F, the coldest cone (05) is just starting to soften. Sure enough, the kiln was too cold

So I bumped it up to 1950F and it fired to a perfect Cone 05, but still a little too cold

I put in my 2 new tiles and fired to 1975. Perfectly fired at Cone 04 (the tip of the 04 was missing to start, I didn't put in an 05 because I already knew it would melt at 1975F). If everything remains constant, that should be a good temp to fire to.

One of the tiles cracked in the kiln. I'm patching it with some Magic Mender and will glaze them soon. You can see three more Orton cones in the middle, 07, 06, and 05. Will use those to test my 06 glaze temperature.