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engobe/slip

updated fri 18 jan 02

 

Tommy Humphries on tue 15 jan 02


What do you call a slip that is not mixed with water, but with some other
suspender, such as glycerin, turpentine or diesel oil ? I had the
impression that these were engobes, but I guess I was wrong...

Tommy


----- Original Message -----
From: "vince pitelka"
To:
Sent: Tuesday, January 15, 2002 8:05 PM
Subject: Re: Engobe/Slip


> The commonly used definitions among many ceramics professionals are that a
> slip is essentially just clay or claybody thinned with water, and perhaps
> with flocculants or deflocculants added. An engobe is, as someone else
> suggested, somewhere between a slip and a glaze, and is formulated for
> application to bone dry and bisque-fired wares. Engobes generally contain
> some calcined clay to reduce shrinkage after application. They also
usually
> contain additional fluxes to ensure adhesion, often a little borax to
assist
> adhesion early in the firing.
> 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/
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>

Gwyn Ace on tue 15 jan 02


Glen Nelson states...an Engobe is essentially Clay Slip.
Leach refers to Slip or Engobe.
It seems that slip is generally called just that in England etc. but is =
frequently called Engobe in America.
Just to confuse things..we make the clay into a slip before sieving out =
impurities.........and then we have casting slip.We have slip/engobe =
with a low shrinkage for use on dry or biscuit pots..and to complicate =
things further.. we have slip glazes( a glaze which is mainly clay) and =
self glazing slips ( which are often almost the same as a slip glaze)
The main thing is to have a mixture which will achieve the result you =
want and the name you fix on it may depend on your tutor's or =
colleague's preference.
GWYN in N.Z.

vince pitelka on tue 15 jan 02


The commonly used definitions among many ceramics professionals are that a
slip is essentially just clay or claybody thinned with water, and perhaps
with flocculants or deflocculants added. An engobe is, as someone else
suggested, somewhere between a slip and a glaze, and is formulated for
application to bone dry and bisque-fired wares. Engobes generally contain
some calcined clay to reduce shrinkage after application. They also usually
contain additional fluxes to ensure adhesion, often a little borax to assist
adhesion early in the firing.
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/

vince pitelka on wed 16 jan 02


> What do you call a slip that is not mixed with water, but with some other
> suspender, such as glycerin, turpentine or diesel oil ? I had the
> impression that these were engobes, but I guess I was wrong...

Tommy -
I would call them goo, but I have not had experience with such slips. What
would you use them for?
- 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/

Denise Philipbar on wed 16 jan 02


I would call this a slip because you haven't added anything that would make
it flux more than a slip. Actually, the glycerin, turpentine and diesel oil
only help keep the clay particles from sticking together (like a
deflocculant, kinda sorta) so they are more brushable (if that's a word).

I know what the glycerin does...it "wraps" itself around the clay particles
to keep them separated from each other so they won't cling together,
allowing them to move more fluidly against one another...like a lubricant.
I suspect the diesel oil does the same thing and perhaps the turpentine, but
these would be more stinky. However, glycerin won't work if it's too warm
(say over 90 degrees Fahrenheit). When the glycerin gets warm, it thins
enough to let the clay particles get cozy again and flocculation occurs.

I have used gum/glycerin to suspend oxides and carbonates more than
clay...these I call stains.

Hope this helps!
Denise


-----Original Message-----
From: Tommy Humphries [mailto:thump@shreve.net]
Sent: Tuesday, January 15, 2002 9:42 PM
To: CLAYART@lsv.ceramics.org
Subject: Re: Engobe/Slip


What do you call a slip that is not mixed with water, but with some other
suspender, such as glycerin, turpentine or diesel oil ? I had the
impression that these were engobes, but I guess I was wrong...

Tommy


----- Original Message -----
From: "vince pitelka"
To:
Sent: Tuesday, January 15, 2002 8:05 PM
Subject: Re: Engobe/Slip


> The commonly used definitions among many ceramics professionals are that a
> slip is essentially just clay or claybody thinned with water, and perhaps
> with flocculants or deflocculants added. An engobe is, as someone else
> suggested, somewhere between a slip and a glaze, and is formulated for
> application to bone dry and bisque-fired wares. Engobes generally contain
> some calcined clay to reduce shrinkage after application. They also
usually
> contain additional fluxes to ensure adhesion, often a little borax to
assist
> adhesion early in the firing.
> 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/
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>

____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org

You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/

Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.

Tommy Humphries on thu 17 jan 02


Once upon a time hydraulic pressed pots were liberally dosed with diesel oil
and stearic acid as a lubricant/release agent... when banding these bowls
before the clay dried out many non water based colored slips were used, as
water based ones would bead up on the oily surface of the pot.

Tommy


----- Original Message -----
From: "vince pitelka"
To:
Sent: Wednesday, January 16, 2002 8:51 PM
Subject: Re: Engobe/Slip


> > What do you call a slip that is not mixed with water, but with some
other
> > suspender, such as glycerin, turpentine or diesel oil ? I had the
> > impression that these were engobes, but I guess I was wrong...
>
> Tommy -
> I would call them goo, but I have not had experience with such slips.
What
> would you use them for?
> - 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/
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>