A clay stumper question for you.
My brother works for a ceramic tile company, and recently called me with a clay question that has him (and now me) completely stumped.
They roll out slabs of commercial clay fresh from the bags to make their tiles. Fresh out of the bag, the clay is perfect. When they cut out the squares from the slab, the edge scraps (still soft and pliable) get pugged using a de-airing pug mill. The ONLY thing they add to the soft scraps is a bit of water.
The pugged clay is now always completely short and breaks apart when they try to run it through the slab roller. The only way they can stop this, is by adding "too much" water, which makes the clay sticky and hard to use for their production purposes.
I asked him a ton of questions, trying to figure out the problem, but can't find the obvious answer.
My brother has been working for the company for 4 years, using the exact same process, and this problem is brand new.
They are using the same clay body they've always used.
They buy their clay in multiple ton loads, and are using clay from the same shipment that originally they had no problem with.
The clay has not been frozen and then thawed.
As mentioned above, nothing other than a small amount of water is added to the clay when it's pugged.
Does anyone out there have any idea what could be causing this problem? I'm stumped.
Thanks in Advance for any info you might have.