Vince Pitelka on thu 4 sep 97
Just a little afterthought regarding yesterday's comment about vinegar and
deflocculants/flocculants. Many white slips made from standard ceramic
materials come out a little alkaline, which can be a disaster in decorating
slips, since they are in effect deflocculated. When you deflocculate a slip
it becomes "super-flowing." If you are depositing a slip heavily on a
surface, as in slip-trailing, feather-combing, marbleizing, etc., you do not
want a super-flowing slip. You want it to stay where you put it, and you do
not want the colors to intermix unless you cause them to do so by
manipulating them. When I first started trying to do feather-combing on
vertical surfaces I had a hell of a time, even with a slip which was not
purposefully deflocculated. On a hunch, I mixed up a saturated solution of
epsom salts in hot water, and added a few drops to the problem slips. They
immediately thickened an incredible amount, indicating that they were in
fact deflocculated. So, by adding a little epsom salts concentrate, or a
little vinegar, we neutralize any alkalinity which may be present due to the
washing of kaolins or other processing of raw materials. If you have been
having trouble with slips flowing or intermixing too readily in application
and manipulation, try flocculating them just a bit. You will be amazed.
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
1560 Craft Center Drive, Smithville TN 37166
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