Friday, August 6, 2010

16 Glazes, 80 Test Tiles!

Glazing is truly my weak point at this time.
I have a terrible time getting predictable results of late.
So I bit the bullet and did a whole lot of testing, with a mixed bag of results.
Please to enjoy...




Notes:
This was a cone 10/11 reduction firing.
My kiln is a small (3.5 cubic feet) electric, converted to a propane updraft. I did some experimenting with the load as well as the glazes...

On the bottom shelf, I posted around the edge of the round shelf, using 8 posts.
On the middle shelf, I places posts on their sides, 2 rows tall, creating a sort of saggar around the tiles, with just enough opening in the "enclosure" for the cone pack
The topmost shelf was covered with a shelf posted with just 4 posts, and then a baffle shelf was placed on that about 3" under the flue opening.

This was a single-fire load, on bone dry greenware -  I used 2 clay bodies - a high iron, groggy clay (Sandstone Buff from Quyle Kilns) and a white/gray body (SilverStone, also from Quyle).

For each glaze, 5 tiles were used - 2 of the dark body and 2 of the light body were dipped either 1/2 or 2/3, with 1 tile of each body being placed on the middle and top shelves.
A 5th tile of the combined bodies was glazed, with washes of red iron oxide and rutile brushed on both under and over the glaze. All the washed tiles were placed on the lowermost shelf.

The "saggared" shelf (the middle shelf) had much more reduction, which is noticeable in the bare clay at the bottom of each tile.
The tiles are numbered:
1= dark body on middle shelf. 2= light body on middle shelf. 3= dark body on top shelf. 4= light body on top shelf. 5 mixed body with RIO and Rutile washed over and under, on bottom shelf.
Click on images to enlarge.
whew!



Shaner Yellow


  • Custer...............29
  • Whiting.............20
  • Talc.....................4
  • Bone Ash............4
  • Zircopax............23
  • Red iron oxide.....4


Notes:
These were all dipped 1/2.
Has significant crawling on the dark body, but none on the light body.
Wonder why...





Melinda's Not Yellow

  • Neph Sye..........58.1
  • Dolomite...........19.3
  • Ball Clay.............3.9
  • Bentonite.............7.3
  • Zircopax............11.4
  • Tin Oxide..........2.1
  • Red iron oxide...0.5
Notes:
These were all dipped 1/2.
Melinda gets lovely blues and creams, breaking to rust.
She says this glaze is best with an RIO wash underneath, and better on bisqued  clay.
I didn't have any Tin Oxide, so I subbed more Zircopax.


Candace Black

  • F-4 Feldspar..........65
  • Whiting.....................5
  • Silica......................20
  • Kaolin......................5
  • Red iron oxide..........8
  • Colbalt carbonate.....5
Notes:
Just fail.
From "Complete Guide to High-Fire Glazes", by John Britt. All dipped 1/2.
First (and perhaps most importantly), I didn't have F-4 feldspar, so I used Custer.
Still searching for a nice black...


Snow White


  • Hawthorne Bond.....30
  • Custer.....................10
  • Silica.......................30
  • Oak woodash.........25
  • Zircopax...................6
Notes:
All were dipped 1/2.
Formulated playing around on GlazeSimulator.com .

Just not very pretty.
The glaze called for Tin oxide, so I added Zircopax at twice the amount. Again, crawling on the dark body, but not on the light. The dark body has much more tooth. 


Orange Peel


  • KMS Kaolin.....20
  • Custer.....31
  • Talc.....34
  • Silica.....15
  • Copper carbonate.....0.05
  • Copper oxide.....0.05
Notes:
Dipped 1/2. Again, playing with GlazeSimulator.com . This one has potential I think. Its satiny and touchable. I like what its doing over the Rutile wash. I think I might either sub Rutile for the coppers or just add it in. Might also try an addition/substitution of Chromium oxide.


Coleman Tea Dust

  • Custer.................40
  • Silica...................25
  • Whiting................16
  • Talc.......................7
  • Red iron oxide.....10
Notes:
Dipped 1/2, should have defloculated a bit and dipped 2/3 I think.
First, I didn't do a slow cool-down in this firing, so I didn't get any crystallization, but I knew that would be the case.
I really like how it reacts both over and under the Rutile.
Its a keeper...


No-Barium Blue

  • Strontium................31.9
  • Neph sye................53.1
  • Ball clay....................6.7
  • Silica.........................8.3
  • Copper carbonate.....4.0
  • Bentonite...................1
  • Zircopax..................10
Notes
1/2 dipped. From the article "Leaving Bariumville" on CeramicsArtsDaily.org .

The original recipe looked lovely on porcelain, but not so good on my clays. I didn't like the translucent quality, so I added the Zircopax for opacity. I like it much better now, and actually prefer it on the dark body.

Don't think it works with any of the washes.


Bone Ash white

  • NC-4 Feldspar.....40
  • Kaolin.....25
  • Dolomite.....30
  • Bone Ash.....5
  • Bentonite.....3 
Notes:
From the book "Complete Guide to High-Fire Glazes" by John Britt.

#1 & #2 - single dipped. #3 & #4 twice dipped. #5 single dipped.

I didn't have NC-4 Feldspar, so used Custer. I really like this on tile #4, though it crazed a fair amount.


Haynes White

  • Neph Sye.....45
  • Silica.....30
  • Whiting.....8
  • Dolomite.....10
  • Talc.....7
  • Bentonite.....1
Notes:
Dipped once, glaze was a cream consistency. From the book "Complete Guide to High-Fire Glazes" by John Britt.

Well...Its essentially a clear glaze.
It has something of a chun quality to it, and as you can see, is very different in heavier reduction.
Anxious to see it in an Oxidation firing.
I really like the life it has both over and under RIO,


Ostman's green Crackle


  • Neph sye...............55
  • Dolomite................23
  • China clay..............21
  • Silica........................1.25
  • Copper carbonate....0.75
Notes:
Dipped 2/3. From Lasse Ostman's glaze page.

When Mr Ostman uses this glaze, thinly, on a white body, in oxidation, he gets a lovely matte green crackle,

I wish you could feel this glaze and see it in person. Its so alive...I love ll its incarnations.
You can't tell here, but that red on tile #5  is crystal formation - perhaps encouraged by the RIO wash...


Gary's Gold


  • Dolomite.............21.02
  • Whiting...............10.51
  • Custer.................36.84
  • Silica...................31.63
  • Bentonite...............5.3
  • Ritile....................10.51
  • Red iron oxide.....10
Notes:
Dipped 1/2. From Gary Kelsey, Trenton, Mo.

One of my favorite, most consistent glazes. I just love it. More crystals on an iron rich body, but nice either way. Not really effected by either of the washes, but a dip of Celedon over it produces great effects.


Ohata Red



Notes:
Dipped 1/2 - best with 1 thin dip.
Shoot! Can't find my recipe right now.
I don't really like this glaze on its own, but under ash glazes it does crazy-wonderful oil-spotty type things.
tile #5 is showing over and under Rutile.










3/3/3 chrome Ash


  • Redart.....33.3
  • Silica...33.3
  • Wood ash...33.3
  • Chromium oxide...4
  • Bentonite....1
Notes:
1/2 dip. I was just playing around...so while I'm sure others have made this same glaze, its just out of my head.

I've mixed it up with Rutile, Copper oxide and with no oxides. I like it because it doesn't run, and has a lot of life to it.
I don't use it inside functional ware.
Tile #5 shows it under Rutile.


333 Chrome Ash Over Rutile


Notes
Half of each tile (vertically) is washed
 inside and out with Rutile. 
You can see the difference I think.

I find the more texture a piece has, the more interesting it is.












Well, that's all I have.
I always get such good feedback from fellow potters when I post here, and I'm pretty anxious to hear everyone's thoughts.

I'll be doing another test next week  same process, but in an oxidation atmosphere.
Looking forward to that!
thanks for taking a look!
CMCK


5 comments:

CorazondeDios said...

sweet! nice test results! I rike! I rike!
I like that you did it on different clay bodies, and did one with a rio wash, too.

Ann said...

Hi Cathi- I really enjoyed my quick look this morning- thanks for posting your tests..Ann Brink

TexasMac said...

Boy, you were busy.....hope it leads to great firings in the future! I haven't been on facebook for forever....I am on a pinchpot kick...love Melinda

crutch said...

I found your blog through a link on clayart and sat this morning with my peanut-butter/toast and coffee and perused all your post. Surely did enjoy what you have done. -carl
http://www.flickr.com/photos/crc0823/

Cindy said...

I'd be interested in more information on your converted kiln. Do you have a post explaining your modifications?
Cindy

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