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spiral cracks/canvas bats

updated sun 16 dec 01

 

Cindy Strnad on thu 13 dec 01


Well, I tried the canvas bats, and after a little
getting used to them, I really like them. Problem
is, now I seem to have a rash of spiral cracks on
my hands. Of course, the basement is drier than
normal, but I don't think that's the problem. Any
ideas? Here's what I did:

First, I tried not trimming at all, as I liked the
look of the canvas pattern. Noticed the cracking,
so next time I did trim and burnish, but I still
got cracking. I added grog to the clay, which
seems to have helped, but I'm still seeing cracks.
Suggestions?

Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com

Dale Neese on fri 14 dec 01


Cindy, first compress the bottoms with a rib back and forth across the =
bottom, not just from center out.
Even though you like the pattern on the bottom of your ware, don't let =
the pots dry on the bats. Cut and remove the pot and place it on several =
layers of newspaper on a flat surface. After a while, flip the newspaper =
over and place the pot on it again to dry to leather hard. When the =
newspaper is done for, throw it in the recycling bin. If you throw to =
the right thickness and don't need to trim, just recenter the pot upside =
down on the wheel and briefly burnish the bottom on the outside edge. I =
do this for most everything I throw except bowls where you need a nicely =
trimmed foot. I still place the bowls after trimming on newpaper to dry. =
Rarely do I use bats but it is better that you remove your pots from the =
bats as soon as you can. Use another bat to help flip your larger pieces =
over without having to handle them, put a sheet of newspaper on the rim =
first.=20
I hope this helps with the spiral cracking.=20
Dale Tex

vince pitelka on fri 14 dec 01


> Well, I tried the canvas bats, and after a little
> getting used to them, I really like them. Problem
> is, now I seem to have a rash of spiral cracks on
> my hands. Of course, the basement is drier than
> normal, but I don't think that's the problem. Any
> ideas? Here's what I did:

Cindy -
I am glad to see that someone else out there is as lysdexic as I am, often
writing words other than what I mean. I was trying to envision spiral
cracks on your hands. It was not a pretty picture.

I have never encountered this, and I have used the canvas for both stoneware
and porcelain. Are you removing the canvas as soon as the pots are stiff
enough? You do not want to wait any longer than necessary, because of
course the stuck canvas will prevent the bottom from shrinking as it should,
and if you wait too long that could result in surface cracks. I always
remove the canvas AS SOON as I can carefully pick up the pots with
distorting them.
Best wishes -
- Vince

Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/

Dannon Rhudy on fri 14 dec 01


...... tried not trimming at all, as I liked the
>look of the canvas pattern. Noticed the cracking,
..... added grog to the clay, which
>seems to have helped, but I'm still seeing cracks....

I've not had problems, even with large platters and
servers - say 18" or so. I DO pull a wire beneath
the canvas before I remove it from the wheel, so
that the clay can shrink without undue stress. If
you already do that, then - how thin is the base?

regards

Dannon Rhudy
.

Cindy Strnad on sat 15 dec 01


Spiral cracks on my hands--you're right, Vince.
That would be very bad. Would make it hard to
throw. Yes, I took the canvas off pretty quickly.
As quickly as I was taking the tile bats off, at
least. And set the pots on their little rims.
Maybe, after all, it is the drier air of winter,
and the cracks just happened to happen right after
I started using the canvas bats.

Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com

Cindy Strnad on sat 15 dec 01


Hi, Dannon.

Strangely enough, I didn't have problems with
plates and platters. Just mugs and bowls. They
seem the same as they've always been (aside from
the cracks). Since neither you nor Vince have had
problems with this, my present thinking is that
perhaps the basement was more drier-than-usual
than I thought it was, or else I didn't throw the
bottoms thin enough because I'm used to losing
quite a lot when cutting them off the bat. At any
rate, now that I know it's not the bats, that'll
make it easier to figure out what it actually is.
Thanks. :)

Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com