potterybydai on wed 13 feb 02
I am going to try this on my own, but wonder if anyone else has had the same
thought, or already worked it out-----slip made with water that has Darvan
(defloc liquid) in it SHOULD have less shrinkage than slip made with just
water, right? I'm thinking that this slip may work better for using on dry
or leatherhard pots. So should a sugar-water mixed slip, if it would have
the same properties as the "magic party trick" from a year ago or so
(kneading sugar into really firm clay to soften it to patch greenware). On
the other hand, given the properties of vinegar to sort of "eat" into clay,
then a slip made with vinegar-water should adhere to the dry clay more
readily. Definitely need to experiment with these variations. If I do all
the varieties on the same tall cylinder, at various stages of drying, or
even after bisque, then kiln position, etc. shouldn't have any bearing on
the results. Will let you all know how I make out.
Dai in Kelowna, BC, fighting a "beast of a cold" as my grandfather used to
say.
potterybydai@shaw.ca
Life is 10% what happens to you, and 90% how you
respond to it.
David Hendley on thu 14 feb 02
Hmm, if you really mean 'trailing slip', and you want to use
techniques such as feathering, then I think Vince is correct,
and you don't want to lose the surface tension of the slip
by deflocculating it.
On the other hand, deflocculating slip can allow you to get
a thicker coating of slip on the surface with less water.
I regularly use slip-glazes that that are so thixotrophic they
will pass the 'Blizzard test': an undisturbed tub of slip can be
inverted and it will stay at the bottom of the tub, but once
stirred, it becomes easily brushable. These slips can be made
extremely thick, and they stay put pretty well even when
brushed on vertical surfaces.
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
----- Original Message -----
From: "potterybydai"
To:
Sent: Wednesday, February 13, 2002 1:42 PM
Subject: defloccing trailing slip
> I am going to try this on my own, but wonder if anyone else has had the
same
> thought, or already worked it out-----slip made with water that has Darvan
> (defloc liquid) in it SHOULD have less shrinkage than slip made with just
> water, right? I'm thinking that this slip may work better for using on
dry
> or leatherhard pots. So should a sugar-water mixed slip, if it would have
> the same properties as the "magic party trick" from a year ago or so
> (kneading sugar into really firm clay to soften it to patch greenware).
On
> the other hand, given the properties of vinegar to sort of "eat" into
clay,
> then a slip made with vinegar-water should adhere to the dry clay more
> readily. Definitely need to experiment with these variations. If I do
all
> the varieties on the same tall cylinder, at various stages of drying, or
> even after bisque, then kiln position, etc. shouldn't have any bearing on
> the results. Will let you all know how I make out.
> Dai in Kelowna, BC, fighting a "beast of a cold" as my grandfather used to
> say.
> potterybydai@shaw.ca
>
vince pitelka on thu 14 feb 02
David Hendly wrote:
> I regularly use slip-glazes that that are so thixotrophic they
> will pass the 'Blizzard test': an undisturbed tub of slip can be
> inverted and it will stay at the bottom of the tub, but once
> stirred, it becomes easily brushable. These slips can be made
> extremely thick, and they stay put pretty well even when
> brushed on vertical surfaces.
David -
I think this is what makes the difference. I have done a lot of
slip-trailing, feather combing, and marbling, and in my experience
deflocculated slips do not work for that (as you point out). Regarding
using deflocculated slips just for surface coating and brush painting, I
think I have probably never mixed them thick enough. And besides, I have
never had any problems with flocculated slips, so I have had no reason to do
further experimentation with defloccuated slips.
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/
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