Wednesday, September 1, 2010

Latest Firing Results

Ok then...
My second load of ware that was glazed with the spraying technique, and I can see I need to learn to better judge my glaze thickness.
I also need to develop some reliable method for a slow cooling of the kiln to encourage crystals in my Tea Dust.
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This was a cone 11 reduction firing, though for some reason I didn't get as much reduction as I typically do.
Everything was raw glazed and single-fired.
Kiln was soaked at about 1800 degrees, and then light reduction was started.
Occasionally I added a couple of sticks of wood with an idea of increasing redux and adding some fly ash, but it smoked so much that I realized I had better wait till I could contact the local fire dept first to let them know I was not torching the Mother Lode to the ground.

Everything but a few test tiles was Quyle Kilns Sandstone Buff - an irn rich clay that is typically nice and dark in redux.




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Malcolm's Shino


Neph Sy.................40.9
Kona........................9.8
Kaolin.....................18.2
Ball Clay.................13.8
Redart.......................6
Soda Ash................17.3

From John Britt's "Complete Guide to High Fire Glazes"
Dipped 2/3 on damp clay. Tested on 2 dark and 2 light tiles, with the last tile having both Red IO and Rutile washed over and under the glaze. On one each of the light and dark tiles, I sprinkled a little coarse salt, thinking it might create some variation in surface moisture/soda ash migration (if I understand the theory behind carbon trap shinos...)
I guess I expected something more spectacular.
Anyone have any thoughts?



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Penn State Shino


Neph Sy .......................14.6
Kona..............................34
Spodumene.....................29
Kolin................................9.7
Ball Clay...........................4.9
Soda Ash.........................7.8


From John Britt's "Complete Guide to High Fire Glazes"
Dipped 2/3 on damp clay. Tested on 2 dark and 2 light tiles, with the last tile having both Red IO and Rutile washed over and under the glaze. On one each of the light and dark tiles, I sprinkled a little coarse salt, thinking it might create some variation in surface moisture/soda ash migration (if I understand the theory behind carbon trap shinos...)
Again, I guess I expected something more spectacular.


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Matte Black

Don't laugh...I forgot to add the colorants!

Cornwall Stone.....................42
Dolomite...............................15
Whiting.................................10
EPK.....................................23
Silica....................................10
    (forgot) Yellow Ochre........6
    (forgot) Cobalt Carb..........2
    (forgot) Chrome Ox...........1

From the March/April 2010 issue of PMI .
Dipped 2/3. Tested on 2 dark and 2 light tiles, with the last tile having both Red IO and Rutile washed over and under the glaze.
Now, Ms Bohls explains that she fires cone 10 electric, but I couldn't see any reason this glaze wouldn't work in my kiln. I did put the pieces on the top shelf, which typically gets very little reduction (its right under the flue.). Wonder why its not at least matte...



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Malcolm's Shino under...

Left to right:
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Shaner Yellow
Matte Black
Melinda's Not Yellow




Another tile with the Shaner Yellow over the Malcolm's Shino.
I am really liking this!
Definitely want to use this combo!










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A Couple "Matte Black" Items

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OK, I was expecting this butter dish to be Matte Black.
I still like it! It has a Rutile wash under it and has some nice interest.
Not as dramatic as I had hoped, but in looking at it, I wonder if it really would have been as successful if it was black.

On the other hand, I think this spice shaker would definitely have been more successful and dramatic in the black.
I think I will re-glaze this piece...its just not doing anything for me as is.






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A Few "Melinda's Not Yellow" Items

Well, I just love this glaze, and am so grateful to my Stay-at-Home mug exchange partner Melinda Collins for sharing it with me!

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A couple of spice shakers. The one of the left has an RIO wash under the glaze.

Wren House - I'm just starting to develop this. Put my own stamp on it.
2 things...
I found I have a weak spot on the neck when I alter the lip, but sticking a wad of clay there and stamping in my chock seems to solve that issue.

That blue streak is a piece of copper tape I got at the hardware store. Thought it would be fun to play with. Might do better over the glaze rather than under it.







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A Few "Coleman Tea Dust" Items


I did not spray this glaze thickly enough, and I'm having some issues cooling my kiln down slowly enough, but overall, its a nice glaze on just about anything.

Salt and Pepper shakers - what's to say?
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Another Wren House.
I think they should be a little larger, and I had some issues with correcting for torque. The houses were pretty wet when I cut the keyhole in the back for hanging. As they dried, the keyhole moved so now they will hang kinda wonky.

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Butter Dish...
The glaze was fine on this one, but its pretty warped. Not funky/good warped, but poorly executed warped.
I had a sushi tray in this load that looks like a record left in the sun too!
I need to make the slabs for these butter dishes thicker, and handle them less. Rutile wash under this BTW.

This was kinda interesting.
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That's a piece of that copper tape, cut into a pattern and applied to the tile before glazing. This pic is a bit over-corrected, and I don't think the results were all that attractive - a dark indigo matte area), but it was interesting to see what happened.

That's pretty much it.
As usual, I welcome input, critique, suggestion and comment. I always learn so much from you all.
Thanks for having a look!
CMCK

6 comments:

Kartott said...

Great blog!

Marian said...

Cathi, at the time the PMI article came out with the Margaret Bohls glazes, I emailed her about the matte black glaze. Specifically, I asked her about whether or not it worked well in reduction. She replied that it was even better in reduction than oxidation and to go for it. I did and it's become one of my favorite glazes. It works well over shino glazes with wax resist design on the shino for a lovely pattern with the black.

So go for it and put that black glaze anywhere in the kiln!

Marian

the Square Peg said...

Thanks Marian!
Will report my results...

Melinda Collins said...

Things are looking up! Some great glaze tests....I gave up on Shinos too quickly......you are onto something...Melinda

Brixvold said...

ok, your soda ash shinos:

1. let them dry until you get soda crystals growing on the surface. These are the necessary ingredient of the amazing pieces Malcom does.

2. begin reduction earlier, when the soda ash melts it traps the carbon. Thus if you don't reduce early enough you wont get anything but white.

I'm just doing a firing now, that hopefully will give better results than the last couple of test firings, which were whitish ;)

Brixvold said...

-a firing with penn state and m. davis shinos that is.

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