Biscuit Firing at 800deg centigrade

[steviepeas]

18 hours ago, High Bridge Pottery said:

I always turn off auto-correct, causes more issues than it solves.

 

Sorry for going off on a tangent steviepeas, let us know if you try a 700-800c biscuit and how it turns out.

So, I undertook an 800c biscuit fire and the only difference I noted was the fired ware  was not quite as white as usual for my 1040 fire temperature. No difference in strength, just a shade darker, which must mean something.  I then fired a glaze kiln to 1040c,( EW) with some of the glazed 800c biscuit ware and the normal white shade reappeared, no pinholes or any visible crazing. (. I usually mix biscuit and glaze firing at 1040 for efficiency if I don’t have a load full of each.)  One other question… I hear the “biscuit high and glaze low “ quote often,  but what is the consensus on the temperatures for each of those…. low and high ? 

[High Bridge Pottery]

Good to hear it worked out  Not sure about the shade darker, could be due to it being higher porosity/less dense or that's what colour it looks at an 800c firing. Might be down to carbon but I am doubtful. 

 

Not sure there's a right temperature, I have read the hotter you fire the higher the COE of the clay but I guess as you are still firing the clay to 1040c then it's still the same COE. I have no data to back up the claim other than people telling me about shivering issues with premade bisque when fired hotter due to higher COE of the body. The lower glazing temperature is just chosen from what works best for the glaze I guess.

[glazenerd]

All information is sourced from PhD’s (Ceramic Engineering) that I collected over the years.