Cone 6 colour tests

Date: 9 April 2018
Clay: Keanes Stoneware 7

Following on from last week's Cone 6 tests. Adding different colour oxides in 50-50 mixture for HP and four different colour tests for 14Pine.

HP 
Colour tests 50:50 grid

Mixed up 250gms of Base Glaze and then divided it volumetrically into 5 equal batches.
Started the five test pots with double strength as they will be diluted by 50% when combined with another pot.

Added colourants as below:
A - 3% Copper Carbonate
B - 2% Cobalt Carbonate
C - 6% Red Iron Oxide
D - 12% Rutile flour
E - 8% Titanium Dioxide



14 Pine Street
Colour variations

Mixed up 200gms Base Glaze and divided it into four batches.
Added these colourants
1 - 0.375% Cobalt Carbonate, 6% rutile
2 - 0.25% Cobalt Carbonate, 3.5% Titanium dioxide, 2.25% Copper Carbonate
3 - 0.25% Cobalt Carbonate, 2.25% Copper Carbonate
4 - 0.25% Cobalt Carbonate, 3% Red Iron Oxide

Cone 6 tests

Three tests in recently fixed kiln.

Date: 7th March 2018
Clay: Keane's Stoneware 7

Hopeful Potter Matte

40      Potash Feldspar
20      Whiting
25      Eckalite (China Clay)
15      Silica

John Post Calcium Matte [JP. JPSM]

30.2    Ball Clay FX (Kentucky OM)
5.7      Frit 3134
32.5    Nepheline Syenite
16.3    Wollastonite
4.9      Whiting
10.4    Silica (Flint)

14 Pine
4.03     Frit 3124
28.20   Potash Feldspar
16.11   Whiting
19.17   Eckalite
32.50   Silica


Love them all.
Surprised JP wasn't more matte.
HP is lovely, read later its for ^8? Seems okay though, I"m going to perservere.
14 is taken from my Currie grid test at Pine Street. Initially I'd chosen another square but later it crazed so I went with another mix that hadn't.

Now to test with colour!

Earthenware tests 18/2

Out of the kiln this morning a number of Earthenware cone 04 glaze tests.
I'm still just trying to find successful base glazes, retesting some of the recipes I've tried before to make a base line for revisions.

All were fired to 1080 degrees Celcius on Keanes Earthenware tiles bisque fired to cone 04.

Worthington Clear 
EW cone 04

Gerstley borate     55%
Eckalite                30
Silica                    15

Results
Very clear glaze, some bubbles in suspension in thickest parts.




ABEM 
cone 04

Frit 3124               50
Eckalite                15.65
Whiting                16.65
Silica                    17.75
Total                            5

Results
Nice smooth matte glaze

EB* 
clear EW, cone 04

Frit 4131              83.3
Eckalite               16.6
* batches 2 and 3 combined and whizzed up to be smoother

Results
This seems quite matte even though its a clear recipe. Much better results from first try when I must have put incorrect amounts in. Whizzed up. Need to buy a sieve.




Julie's Satin
cone 04

Whiting                   17
Gerstley borate        27
Lithium carbonate     6
Nepheline syenite      4
Eckalite                    12
Silica                        34

Results
This glaze is still cracking. Which is a pity because I like the quality of its matte surface.
Will maybe try to modify it though I have tried before with no improvement.





Satin Base SB

Results
This is the old batch remixed. The white version of this has a tendency to late crazing which is a pity because I really like the creamy surface of this.

Earthenware tests 10/2/18

AB Clear glaze Frit Eckalite LB revised to use Strontium carbonate LB revised to use Whiting


 

Five Earthenware Base Recipes

Originally written 26 Sept 2016

Testing of five different Cone 04 matte or satin base recipes. All of the recipes have very similar ingredients, but different ratios.

These tests weren't ultimately successful as a week later four of them had crazed.

Retesting Julie's Satin (JMBC) and also testing a variation (JMBC revA), revised using hints from Glaze Simulator.

 A. Jackie's Matte via Priscilla Hollingsworth

38  Gerstley borate
10    Lithium carbonate
5    Nepheline syenite
5  Eckalite 2
42  Silica

5% Zircosil



B. Satin Base (from here)

65.5 Ferro frit (4124) 3124
11    Nepheline syenite
5      Eckalite
42    Silica

C. Julie's Satin (from here)

27  Gerstley borate
7    Lithium carbonate
17  Whiting
4    Nepheline syenite
11  Eckalite 2
34  Silica

 D. Hirsh's Satin Matte

32  Gerstley borate
9    Lithium carbonate
17  Whiting
4    Nepheline Syenite
4    Eckalite 2
35  Silica

2% Bentonite

 E. Julie's Matte revised to fix crazing (JM rev A)

27  Gerstley borate
6    Lithium carbonate
17  Whiting
4    Nepheline syenite
12  Eckalite 2
34  Silica