Randy McCall on thu 19 aug 10
I am having trouble with ball crawl glazes drying=3D2C cracking and then fa=
ll=3D
ing off the sides of the pots. Falling off the sides is the problem I woul=
=3D
d like to resolve.
Does anyone have a ball crawl that adheres to the pot better than I have or=
=3D
do you have any tricks you use?
=3D20
This is what I am using.
=3D20
Recipe Name: Lanas Crawl Glaze
Cone: 6 Color: white
Firing: Oxidation Surface: Beaded
Amount Ingredient
60 Nepheline Syenite
22 Magnesium Carbonate
18 Ball Clay Number 1
100 Total
Unity Oxide
.241 Na2O
.077 K2O
.662 MgO
.02 CaO
1.000 Total
.489 Al2O3
.003 Fe2O3
2.023 SiO2
.007 TiO2
4.1 Ratio
75.9 Exp
Calculations by GlazeMaster=3D99
www.masteringglazes.com
------------------------------------
Randy
=3D
DJ Brewer on thu 19 aug 10
I have a very successful crawl glaze that does not fall off -- here is
a piece that I fired to cone 10 two years ago. It gets handled and used
-- nothing falls off.
http://corazondedios.deviantart.com/gallery/#/d1yg9el
I can get you the recipe for it. This IS a cone 10 reduction fired
piece, however.
DJ
On 8/19/2010 6:58 AM, Randy McCall wrote:
> I am having trouble with ball crawl glazes drying, cracking and then fall=
ing off the sides of the pots. Falling off the sides is the problem I woul=
d like to resolve.
> Does anyone have a ball crawl that adheres to the pot better than I have =
or do you have any tricks you use?
>
> This is what I am using.
>
> Recipe Name: Lanas Crawl Glaze
> Cone: 6 Color: white
> Firing: Oxidation Surface: Beaded
> Amount Ingredient
> 60 Nepheline Syenite
> 22 Magnesium Carbonate
> 18 Ball Clay Number 1
> 100 Total
>
> Unity Oxide
> .241 Na2O
> .077 K2O
> .662 MgO
> .02 CaO
> 1.000 Total
> .489 Al2O3
> .003 Fe2O3
> 2.023 SiO2
> .007 TiO2
> 4.1 Ratio
> 75.9 Exp
> Calculations by GlazeMaster(tm)
> www.masteringglazes.com
> ------------------------------------
>
>
> Randy
>
>
paul gerhold on fri 20 aug 10
Randy,
Very often the problem is in how the crawl glazes are applied to the piece.
If you are doing multiple thick coats, allowing the first coat to totally
dry can cause adherence problems. Glazing too thick can cause problems.
Bisque firing too high can hurt adhesion. If brushing allowing the brush t=
o
pull on the glaze rather than flowing the glaze off the brush can be a
problem. Adding gum to the glaze can help with your problem.
Spraying a crawl glaze is really a good way to apply but then you have
thickness issues.
The approach that usually works for me is to brush thin layers of glaze on
the pot. Allow to dry totally and then apply another thin layer. I repeat
this until I just see small cracks appearing in the surface of the dried
glaze. Stop glazing at this point. Usually will result in nice large but
controlled crawl pattern. Glaze is made using a water and gum mix of 50
grams of CMC per gallon of water.
Paul
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