Jonathan Kirkendall on thu 3 mar 05
Hi,
I've had many emails and just wanted to clarify that when I say the
glazes were measured in parts, I meant parts instead of weight, so that
means volume. So sorry to leave that out! I use a quarter cup to
measure ingredients, then stir well, no sieving.
Next glaze tests will include ash and ravenscrag slip. Now to find time
to make the test tiles!
Jonathan in DC
Jonathan Kirkendall wrote:
> Hello all,
>
> Pulled some interesting tests out of the kiln and wanted to report...
>
> Like Alisa, I have been moving more and more towards textured glazes,
> and have found Brian Gartside's work extremely helpful in terms of
> establishing a baseline from which to work. The following tests (except
> for the last) were all inspired by the success of one test from another
> line of experiments, which was ash, blackbird clay, and magnesium carb
> mixed in equal parts. This glaze came out looking interestingly bark
> like - exactly what I've been going for.
>
> I took the ash/blackbird mix and added different ingredients as the
> third. The resulting glazes were much more like what we generally think
> of glazes - melted, smooth, some were glassy - and not the texture that
> I was looking for, but I will take these results and keep moving
> forward, probably adding some mag carb to them to see what happens.
>
> I fire to Cone 6 using John Hesselberth's suggested firing schedule:
>
> 100 F to 220 F
> 350 F to 2000 F
> 108 F to 2185 F
> Hold 18 minutes
> 500 F to 1900 F
> Hold 10 minutes
> 125 F to 1400 F
> off
>
> The following glazes are measured in parts, and have not been tested for
> durability or safety.
>
> 1:1:1 ash, blackbird clay, and frit 3195: semi matt clear amber, pools
> nicely, very runny, smooth covering
>
> 1:1:1 ash, blackbird clay, and soda spar: waxy, dense dark brown, little
> movement of the glaze
>
> 1:1:1 ash, blackbird clay, and spodument: dark brown background, light
> brown rivulets on top, much visual texture, well melted, a little running
>
> 1:1:1 ash, blackbird clay, and petalite: matt, more reddish brown than
> with the spod, overall covering is matt and smooth but two drips are
> shiny, dark brown. Nice feel - smooth and buttery
>
> 1:1:1 ash, blackbird clay, and custer: dark brown, pin holes, undermelted
>
> 1:1:1 ash, blackbird clay, and soda ash: very nice - shiny, stringy
> (like an ash glaze), runny, mahogany red.
>
> I had one more test tile so in my quest for a metallic, dry, rust like
> glaze, I threw together 1:1:1:1 red iron oxide, bone ash, ball clay, and
> magnesium carb, and got a terrific rough lichen glaze, with small
> irregular islands. Today I rubbed white glaze in between the cracks and
> will refire to see what happens.
>
> You can see pictures of these glazes at:
> http://pg.photos.yahoo.com/ph/potterdc2001/album?.dir=/66d7
>
> Jonathan in DC
> waiting for the next winter storm!
>
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