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help with brushability enchancement using on-hand materials

updated sun 12 feb 06

 

Maid O'Mud on fri 10 feb 06


I had a good fall on Tuesday and hurt my knee but more=20
importantly a finger on my right hand. I had it x-rayed=20
(not broken) but very swollen, stiff and painful.

Because of this, I'm trying to keep myself busy with smaller=20
projects - namely jewelry. I'm used to pouring and dipping,=20
but never have brushed glazed. These pieces are so tiny
that brushing seems the only way to go - especially since I
want to use more than 1 glaze per piece.

I have on hand:
macaloid
Vee Gum T
Glycerin
Liquid wax resist

and from the Home Depot paint department: glaze base
(which is used to extend drying time in water based
paints and for faux effects).
=20
My glazes are mixed to dipping consistency.
I'm looking for direction on what/how to
add to my current glazes that will lengthen
the dry time/increase brushability with
materials I have on hand as getting out hurts
too - my car is a 5 speed stick shift :-(

Many TIAs

Sam Cuttell
Maid O'Mud Pottery
RR 1
Melbourne, Ontario
N0L 1T0 =20
CANADA
=20
"First, the clay told me what to do.
Then, I told the clay what to do.
Now, we co-operate."
sam 1994
=20
http://www.ody.ca/~scuttell/
scuttell@ody.ca

Snail Scott on sat 11 feb 06


At 12:12 PM 2/10/2006 -0500, you wrote:
>I'm looking for direction on what/how to
>add to my current glazes that will lengthen
>the dry time/increase brushability with
>materials I have on hand...



I'd go with the glycerin. -Snail

Paulette Carr on sat 11 feb 06


Sam,

I make all my glazes as brushing glazes, and have even turned a
commercial dipping glaze to a brushing glaze. To prepare from
scratch, I add 1-1.5% Veegum Cer (Veegum + CMC) to the dry
ingredients; slake; sieve twice, once through 50m and once through
80m sieves. I then add 1 tablespoon of glycerine/300 grams dry glaze
(not including the colorants), mix and adjust viscosity. As long as
I wet, or wash the bisque, I can brush easily. The first coat
(thinned with water on brush) is just to lay down a ground and rewet
the piece. There after, the brushing goes easily. I use 3-6 coats
depending upon whether the glaze requires a thick or thin
application. The CMC add a hardness to the dried glaze coat so that
the pieces can be handled, or further coated with additional glaze.

To add to an already prepared glaze: You can determine how much
veegum is required, by measuring the specific gravity, and
calculating the amount of solids in the glaze (see the archives for
Brogniart's formula- specifically: post: 20 Jan 2004, Dave
Finkelnburg, Re: dry vs. wet weight for glazes ...). Determine how
many grams of the Veegum you will need to add to that volume of glaze
you want to change to brushing glaze. Decant some of the glaze
water, and heat it in the microwave; use that to dissolve the Veegum
T or macaloid. Add this back into your glaze, and sieve 2x through
80m for good mixing and suspension. Add your glycerine, mix and try
brushing with a nice soft brush. The glaze should flow from it. If
not, add more water, or deflocculant to adjust the flow.

If you do have some CMC on hand, you could add a little of that to
harden the glaze shell (0.5-1%). Before I discovered Veegum Cer, I
sprayed my pieces with aqua net hairspray - or fixative. That would
work for your small pieces, but was driving me crazy for the larger
ones.

Good luck, and take care of yourself!

Regards,
Paulette Carr
Paulette Carr Studio
Member/Potters Council
St. Louis, MO