Post #413997 by coruscate on Fri, Oct 17, 2008 10:59 PM

Nice peep hole plugs!

Going back a few threads about the crack.

That sure looks like an S crack.

This is way more common on wheel thrown stuff where you work wetter while spinning the clay than with slip cast or hand built.

If you get a section real wet, especially when working and smoothing with wet fingers or an elephant ear sponge, you expand the volume of the clay when adding the water to it.

When it dries it shrinks in volume because the water has left, leaving the S crack.

The best way to avoid this on your hand built is to wrap it snug in light plastic (like dry cleaners use)and keep it out of the light.

It slows down the drying, but more important it equilabrates the moisture throughout the peice AND then it slows down the drying.

This way you don't have things shrinking at substantially different rates which results in different adjacent volumes that pull and stretch and sometimes crack.

Also, it doesn't hurt to post a kiln god with a good vibe on your firing :)