Ceramic Human

Yeah, I thought about that and it's definitely possible, but I thought I'd ask you guys just to see if it was easy to rule out. There are so many factors, but I'm grateful to have this forum as a resource to help me get acquainted with the process. Sometimes it makes my head spin. I don't want to be an out of touch manager. The more information the better.

I'll crack open the next few that come out. Thanks.

I should have supplied more information. I didn't really give you guys a lot to go on. My bad. I'll look into the tools and possible contamination. A rate of 5/500 is 1% defect rate. I thought if it were a really simple fix then it would be worth reducing defect rates by 1%. Heck, even if it's not a simple fix. You fix two or three problems like this, and reduce your defect rate by half or more. I figure that's worth the time.

This particular glaze is the eggshell from Coyote. We mix a 25lb bags at a time and then sieve using 100 mesh. Not sure on the recipe for the dry mix, but I've attached a photo of the suggested water amount and specific gravity of eggshell. We only sieve after the initial mix. How frequently SHOULD a glaze be sieved?

We're firing in an electric kiln to cone5. Been getting green spots like this on several mugs/week. It's usually only 3-4 out of 500 but that starts to add up over years of business. Do you guys have any experience with this defect?