test glazes Jan. '16

I'm new to mixing my own glazes, so here are my notes on my latest firing. I try to keep in mind variables that may have affected the glazes. I don't have the most precise scale, and when doing a 100g test batch that can have a major affect on the glaze itself. My scale measures to the .1g so the recipes not turning out exactly as expected doesn't surprise me.  I also must note that I'm firing with an automatic kiln sitter to cone 6. These glazes are "midfire" some of which have some specific suggestions on programming a ramp/hold schedule. Some are best at cone 5 and I can see that in some of the results. All the taller tiles are thrown from laguna b-mix, it gives a nice smooth white surface.   The ones in the front are made by just smashing a thick coil in my hand and flattening out the bottom. You will notice a variety of different claybodies used for those. I bought sample packs from laguna in search of a body I like, I will eventually write about my findings from throwing with each of them.

Tomato Red is ^5 and I can now see why. It came out a very ugly brown and seemed to not stay smooth, it took a lot of glaze to make it show.  The thrown tile only had a nice coat on the top corner where it was dipped. The other tile the glaze cracked a lot as you can see. the thin place was where it crumbled off and I was too tired to redo it.

Tomato Red

Tomato Red #13   W/ Bone Ash & Lith)
Nepheline syenite 23.1
3134 10.8
Bone ash 10
Magnesium carb 62
Whiting 7.70
EPK 21
Flint 21.2

TOTAL   100
 
ADD:         Bentonite +2
RIO +12
Lith. carb. +2






Eggshell is nice, it's not too glossy. It breaks a nice brownish color where thin and on the rims. The thicker it goes on the less it breaks the tall tile in the back illustrates this.  bottom third is one brushed on coat, middle is 2 coats and the top is 3.  It doesn't seem to run. the front sample is speckled buff and the speckles break through nicely. The recipe calls for Spanish RIO, which I don't have. It seems to be nice with reg RIO too.

Eggshell

Eggshell ^6 Ox.
Whiting: 9.50
Zinc Oxide: 5.50
FF #3124: 44.50
Custer Feldspar:   20.00
Bentonite: 7.50
EPK: 5.00
Silica: 8.00

Total: 100.00 Grams

         ADD:

Tin Oxide:                 9.00 %
        RIO                                 3.00%

Ron Roy's Licorice

Ron Roy's Licorice.  This one runs if too thick.  You can see the top third is a dark brown because the glaze slid past it. I will be testing it again with thinner application.

Ron Roys Licorice #3
 
EPK 17
Custer feldspar 22
Whiting         4
Talc 5
Frit 3134         26
Flint     26  
  TOTAL 100

Bentonite +2
RIO +9
Cobalt carb. +2

Opal Blue

     This one is bright!! almost blinding... you can see it needs to be a couple layers thick  but runs if too thick. The bottom third is one coat middle is 2 and the top was 3 and I dipped the top 1/4"  you can see that it ran quite a bit where thick.  You can see the one inch of darker blue part on the top,  I think this was from that really thick 1/4" running down, you can see on the very top the glaze melted away from the rim. three brush coats seem necessary.  It does have a lot of cobalt. It calls for 2.5 Cobalt Oxide, which I adjust to 4 Cobalt Carb.

Opal Blue ^6 Ox

EPK Kaolin: 30
Ferro Frit 3134: 50
Silica:     25  
TOTAL: 105

Add:
Cobalt Carbonate                   +4
Rutile: +5

Haynes White

Neph Sy        45
Silica 30
Whiting 8
Dolomite 10
Talc       7  
Total 100





This one I'm not sure of.  It is about as matte as I'd go. almost flat and some roughness to it. I wouldn't be comfortable using it for food.  It reminds me of the zinc base glaze from hasselberth and roy when I left out colorants. (they call for different levels of cobalt carb. and  rutile. and without them it was as though a very thick layer of white icing was on there)

Frog Pond Green

EPK                      31.7
FF3124                 31
Wollastonite         23.2
Silica                    14.1

Copper Carb         2

The recipe calls for different levels of copper carb. .5 is supposed to be a pale yellow/green and 5 is a dark green.   I went with 2 to start with. I like the texture. The tall tile is only one and two brush coats, not thick enough. I dipped the other tester and you can see that it likes to be put on thick.

This is supposed to be dark purple that breaks to black. It is rather light and didn't break through at all. it seems to do as well with one coat as it does three...

Dark Purple

Soda Feldspar         37
EPK 9
Whiting         9
Talc 18
Silica 19
Lithium Carb         8  
TOTAL 100

ADD: Rutile +0.6
Cobalt Carb +3.2
Bentonite         +2.0

These are butterscotch.  The tile and the sample in front of it are the mottled and the one behind it is just regular. from what I've heard of the recipes the should be the same base tone, but the regular butterscotch seems much lighter

Butterscotch

Dolomite 20
Spodumene 20
Frit 3134 20
OM4 Ball Clay 20
Silica 20

TOTAL 100
Add:
Rutile +6
Titanium Dioxide +10




                                                       Butterscotch ^6 Mottled

                                                      Dolomite 20
                                                      Spodumene 20
                                                      Frit 3110 20
                                                      OM4 Ball Clay   20
                                                      Silica        20
                                                           TOTAL 100

                                                      Titanium Dioxide +10


this is Nutmeg

Dolomite                23.3
Spodumene            23.3
Frit 3134                6.8
Ball Clay (OM 4)  23.3
Silica                     23.3 
                              100

Red Iron Oxide     +1.07% 
Yellow Ocher       +3.24% 
Tin Oxide             +4.85% 
Bentonite              +1.94%


Kind of boring when thick. when thinner there is a bit of pale yellow to it that breaks to a light rusty brown. not sure how I like it. might play with it more




That's everything for now... a lot more to play with and some other things to try with these. until then.... don't do anything I wouldn't do, but if you must don't get caught...

A ghastly lack of gerstley: introducing "Carl's Sat. Iron Fuggup"

I ran into the trouble of not having Gerstley Borate when mixing a Saturated Iron and kaki glaze... part brain fart, part naivete, I thought I had ordered Gerstley when in fact I hadn't. I thought g200-hp was gerstly, when in fact it is a potash feldspar. I recognized it when doing the Sat. Iron recipe called for both Gerstley and potash. I found myself adding  the same feldspar as two different ingredients....

I had already made messed up a kaki glaze:

KAKI:

Potash  27           (supposed to be Gerstley)
Silica 25.3
Custer  16.9
RIO  12.8
Talc 11.8
EPK 4.2
Bentonite             2    
                                100

I was in the middle of making the following when recognizing my mistake:

Saturated Iron Glaze  (originally)

Red Iron Oxide 24.6
Gerstley Borate 28.9
Flint 20.2
Potash Feldspar 13.4
Talc 9.4
EPK 3.4    
99.9

  Thick it produces a nonshiny iron red. When Thin it’s a smooth brown, greenish, with hints of blue. Fire to ^6  When over a Kaki Glaze it produces a beautiful copper sheen.  Needs to be thin to get the Tenmoku effect.

In my frustration (because who wants to waste 100g of glaze chemicals) I split the 27 gerstley among the other ingredients as follows:


Sat Iron fuggup:

RIO                  30.6      (+6)
Potash Feld,     28.9      (+15.6)
EPK                 3.4        (+0)
Talc                  9.4        (+0)
silica                 21.6      (+1.4)

I also added :
    Bentonite             2     (+2)
     3134                    6     (+6)


In my amateur rationale, I split it up by my understanding of gerstley.

+6 RIO because I had to put it somewhere and I figured it would act in part as flux characteristic of Gesrtley

+15.6 Potash because I had already measured it out as the gerstley

+1.4  Silica because I thought the RIO's flux quality might do too much

+2  Bentonite because(as I remember) I learned of it's benefit when added to other glazes in helping fit because of its tiny particle size

+6  FF3134 for the borate


I'm not sure of the effectiveness of this, but it seemed to work. I have no idea of its durability or stability and it looks nothing like the copper sheen as advertised by the real recipes with gerstley borate. The modified Saturated Iron looks more like a ketchup glaze as seen on the tile in the back.  the front test is a sample of a sculpture body I tried out. I was able to really gob it on the because of it's gritty texture. the sculpture body has a layer of the kaki with potash in place of gerstley. I may playaround with what we shall call henceforth as "Carl's Sat Iron Fuggup"

Glaze Explorer

I've just begun exploring glazes and claybodies. I've shared things on Facebook, but I'm sure there are friends who have no interest in ceramics, and even less in glaze chemistry.  Every firing I learn new things about glazes, how well they fit different clay bodies or how the respond to different firing schedules.

I have had trouble with memory all my life and even more so since my brain surgery in 2011. Epilepsy has been a major struggle in my life, and through the wonders of modern medicine they were able to locate just where in the brain where seizures originate: my left temporal lobe. It is quite complex, but suffice it to say it wasn't fun.  Seizures affected my life greatly and I haven't had any since then.  A down side of the surgery was it affects my memory. I find it frustrating if I don't document things. I redo things because I forget what I did to get a result or even doing them at times. I greatly prefer the lack of seizures with memory issues versus having no control of when I might have seizures and what I may have been doing at that point.


This blog is to serve as the memory I lack. I've had long periods of time where I was unable to get to the studio and lose track of what happened when. I'm sure there are more to come with the struggles my son faces.  I invite others to use what information they may find useful. I aim to produce enough to gain from the efforts.

CR