Jan Mandrake on thu 12 feb 98
Allison--I too had a terrible time with bottom cracks on pots. I thought it
must be the way I was drying them--so I tried every way to dry more evenly,
etc. The cracks ran from small s-cracks to all-the-way-across-the-plate
cracks. I compressed bottoms so carefully. I stopped using plastic
bats--that seemed to help some, but not all. Then I mentioned this problem to
a potter who threw lots of plates--some pretty thick and massive. She told me
that she always roughly centers the pots and them bangs her fist on the
roughly centered clay--then re-centers it. (She also compresses the bottoms
after she opens up the clay.) I tried it and have not had a single pot crack
since! I also started drying my pots on pieces of drywall (cut to fit my
shelves) that have their edges sealed with wide duct tape (to keep the plaster
from getting in the clay.) Also make sure you cut the pots off the bats asap
even if you don't take them off until they've set up a little. I know this
method sounds a bit unorthodox, but it saved my sanity! Let me know if this
helps!
Bob+Judy Weeden on tue 17 feb 98
Hi, Iwonder if you have solved the cracking problem?
For many years i dug and processed my own stoneware clay. It came from the
foothills of Mount Denali in Alaska. What could be mor romantic? It wasa
beautiful clay body, very plastic, fired to cone 15, was creamy colour in
oxidation, soft tan-gray in reduction,had incredible wet strength. It was
perfect in every way except that it wanted to crack, crack and crack no
matter what was added to it. Since I do a lot of very time-consumuing slip
carving, I couldn't afford to lose pieces. So I learned all the tricks in the
book as well as some that aren't.
Yes, compress, compress and compress some more.
Reverse throw,i.e. after you've opened up, run your finger from periphery to
center several times , moving some clay as well.
Before you center your clay ,put a walnut sized piece on the wheelhead and
dry throw it into a small disc that is thick in the center and fades out to
nothing at the edges, compress this with a credit card, then center your lump
of clay on top of that.
I bet hundreds of people have told you to dry the thrown pieces evenly and
slowly . Rules are made to be broken. I discovered if you dried the pieces
(especially plates and platters) UNEVENLY from the center out it gieves the
rim a chance to still move while the center has already set up. I do this by
wrapping the plates in a piece if plastic in which a large hole has been cut
over the center of the plate.
Good luck.
Judy Weeden
| |
|
