Gold - Cone 6
|
Code # G3868 |
| Materials | Amt | |
|---|---|---|
| Alberta Slip | 35.000 | 35.82% |
| Alberta Slip 1000F Roasted (Alberta Slip) | 35.000 | 35.82% |
| Zinc Oxide | 2.800 | 2.87% |
| Lithium Carbonate | 7.500 | 7.68% |
| Dolomite | 12.800 | 13.10% |
| EPK | 4.600 | 4.71% |
| Additions | ||
|---|---|---|
| Rutile | 1.800 | 1.84% |
Total:99.50
|
Si:Al: 5.4:1 7.5 (Molar:7.0) 18.1 Cost 0.00 per kg |
Notes
*A popular yellow (gold) burning glaze. The surface it develops is a product of crystallization of the iron. Total crystallization such that the normal glossy black surface is covered with a fine mesh of yellow crystals. The glisten they can exhibit gives this glaze its name. That happens when the glaze cools slowly enough, when it cools fast it is jet black glossy.
But this recipe has major issues:
-It shrinks and cracks excessively on drying. To fix that I am using half roasted Alberta Slip here (Alberta Slip is plastic and 70% in a glaze makes it shrink like a clay body).
-The cost to make the recipe, $15/kg, is very high. Lithium carbonate is ridiculously expensive. I want to try alternatives (that will require some chemistry).
-This crazes (the thermal expansion needs to come down).
-As is, this is likely to leach lithium (because of the lack of silica).
Pictures
G3868 gold with roasted Alta Slip vs. Spodumene
Same overall chemistry. Left: Lithium carbonate supplies Li2O. Right: Spodumene supplies it.
Gold using spodumene and frit
Frit version much more fluid.
G3868A flow tests
Fired at cone 6, slow cool to 1400F
#1: G3868
#2: G3868A
#3: G3868
#4: G3868B
For some reason #1 and #3 are the same glaze but have very different amount of crystallization.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Gold - Cone 6" id="146904" key="WvCSaYca" date="2023-10-16" codenum="G3868"> <recipelines> <recipeline material="Alberta Slip" amount="35.000" tolerance=""/> <recipeline material="Alberta Slip 1000F Roasted" lookup="Alberta Slip" amount="35.000" tolerance=""/> <recipeline material="Zinc Oxide" amount="2.800" tolerance=""/> <recipeline material="Lithium Carbonate" amount="7.500" tolerance=""/> <recipeline material="Dolomite" amount="12.800" tolerance=""/> <recipeline material="EPK" amount="4.600" tolerance=""/> <recipeline material="Rutile" amount="1.800" added="true"/> </recipelines> </recipe> </recipes>
Born: 2019-01-14, Modified: 2023-10-16 03:06:40
Gold Using Spodumene
|
Code # G3868A |
| Materials | Amt |
|---|---|
| Zinc Oxide | 3.038 |
| Spodumene | 42.272 |
| Dolomite | 25.759 |
| Ferro Frit 3110 | 21.796 |
| Red Iron Oxide | 3.435 |
| Additions | |
|---|---|
| Rutile | 2.000 |
| Bentonite | 2.000 |
Total:100.30
|
Si:Al: 5.8:1 7.5 (Molar:7.2) 13.1 Cost 0.14 per kg |
Notes
*The sources the Li2O from Spodumene instead of lithium carbonate.
I removed Alberta slip in order to achieve the target chemistry. I found the Frit 3110 supplies the oxides lost from the Alberta Slip (that are not being supplied by Spodumene). Iron Oxide was needed to restore the Fe2O3 the Alberta Slip was supplying.
This will be hard to suspend because it has only 2% bentonite. But the iron will gel it and flocculation should also help. But it will still be far more difficult to use that the G3868 original.
Not to be to ignored is that spodumene is very difficult to work with. At 42% it is down right miserable! And because so much is needed to source the required lithium it brings along all the alumina and silica the glaze needs (leaving no room for clay) to suspend it.
Pictures
G3868 gold with roasted Alta Slip vs. Spodumene
Same overall chemistry. Left: Lithium carbonate supplies Li2O. Right: Spodumene supplies it.
G3868A flow tests
Fired at cone 6, slow cool to 1400F
#1: G3868
#2: G3868A
#3: G3868
#4: G3868B
For some reason #1 and #3 are the same glaze but have very different amount of crystallization.
Dish is old gold, snail tile is this
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Gold Using Spodumene" id="146905" key="fgQYZqHj" date="2023-10-16" codenum="G3868A"> <recipelines> <recipeline material="Zinc Oxide" amount="3.038" tolerance=""/> <recipeline material="Spodumene" amount="42.272" tolerance=""/> <recipeline material="Dolomite" amount="25.759" tolerance=""/> <recipeline material="Ferro Frit 3110" amount="21.796" tolerance=""/> <recipeline material="Red Iron Oxide" amount="3.435" tolerance=""/> <recipeline material="Rutile" amount="2.000" added="true"/> <recipeline material="Bentonite" amount="2.000" added="true"/> </recipelines> </recipe> </recipes>
Born: 2019-01-14, Modified: 2023-10-16 03:13:27
Gold Using Fusion Frit 493
|
Code # G3868B |
| Materials | Amt |
|---|---|
| Zinc Oxide | 3.000 |
| Dolomite | 22.500 |
| Fusion Frit F-493 | 27.000 |
| EPK | 26.500 |
| Red Iron Oxide | 3.000 |
| Talc | 1.500 |
| Silica | 15.000 |
| Additions | |
|---|---|
| Rutile | 2.000 |
Total:100.50
|
Si:Al: 6.2:1 7.5 (Molar:7.1) 15.1 Cost 0.12 per kg |
Notes
*In this one I am sourcing the Li2O from a frit. The frit has low Al2O3, this has permitted adding kaolin, a lot of it. That produces a slurry with good application properties.
The frit is very expensive but I am buying a 50lb bag. My cost is about $800/bag.
The frit has introduced some boron, that is increasing the melt fluidity even more. This appears to be a real benefit because it will permit increasing the SiO2 (that will reduce thermal expansion also).
This one has more KNaO, but expansion is the same. However this should be reduced to reduce crazing.
Surprises:
-This responds to kaolin for increased crystallization (very fine crystalline surface). Al2O3 is normally the enemy of crystal glazes??
-As is, this is not crystallized, even though it is more fluid. But pure alumina is seeding crystals in it. A lot.
-The glaze is so much lower in micro-bubbles and the surface is so much more brilliant.
Next test: Add 5% silica and 0.25 alumina as a seed.
Pictures
G3868A flow tests
Fired at cone 6, slow cool to 1400F
#1: G3868
#2: G3868A
#3: G3868
#4: G3868B
For some reason #1 and #3 are the same glaze but have very different amount of crystallization.
G3868B Ball Melts (with added silica)
On BuffStone clay at cone 6
TR + 10% silica
BL + 20% silica
BR + 40% silica
G23868B with 20% added silica - Cone 6
G23868B with 10% added silica - Cone 6
G3868B with added kaolin/alumina
TR + 10% kaolin
BL + 20% alumina
BR + 10% alumina
L3868B Ball melted on BuffStone clay at cone 6
Slow cool to 1400F
Worst case flow test overflow for G3868
G2868 overflow on flow test one
Crystals growing from edge but not from bottom of glass pool as others.
G3868B + 10% kaolin
Cone 6. Ball melt.
Near edge of sample. Tiny crystals. Cloud of superfine ones.
G3868B + 10% silica closeup
Crystals growing at body:glaze interface
G3868B + 20% kaolin closeup
G3868B + 40% kaolin closeup
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Gold Using Fusion Frit 493" id="147012" key="eozTrTic" date="2020-03-16" codenum="G3868B"> <recipelines> <recipeline material="Zinc Oxide" amount="3.000" tolerance=""/> <recipeline material="Dolomite" amount="22.500" tolerance=""/> <recipeline material="Fusion Frit F-493" amount="27.000" tolerance=""/> <recipeline material="EPK" amount="26.500" tolerance=""/> <recipeline material="Red Iron Oxide" amount="3.000" tolerance=""/> <recipeline material="Talc" amount="1.500"/> <recipeline material="Silica" amount="15.000"/> <recipeline material="Rutile" amount="2.000" added="true"/> </recipelines> </recipe> </recipes>
Born: 2019-01-14, Modified: 2020-03-16 17:29:40
Gold Using Frit #2
|
Code # G3868C |
| Materials | Amt | |
|---|---|---|
| Zinc Oxide | 2.800 | 2.87% |
| Dolomite | 20.000 | 20.51% |
| Fusion Frit F-493 | 25.000 | 25.64% |
| EPK | 24.500 | 25.13% |
| Red Iron Oxide | 2.700 | 2.77% |
| Talc | 4.000 | 4.10% |
| Silica | 18.500 | 18.97% |
| Additions | ||
|---|---|---|
| Rutile | 2.000 | 2.05% |
| Calcined Alumina | 0.250 | 0.26% |
Total:99.75
Auto Unity Formula
|
Si:Al: 7.0:1 7.2 (Molar:6.7) 13.8 Cost 0.11 per kg |
Notes
*This is G3868B with:
-Increased SiO2 and MgO (at expense of CaO) to reduce expansion and melt fluidity.
-Calcined alumina to seed crystals (add more to slurry if needed).
The cost of this is close to the original.
Pictures
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Gold Using Frit #2" id="152186" key="iKte6QbJ" date="2020-03-16" codenum="G3868C"> <recipelines> <recipeline material="Zinc Oxide" amount="2.800" tolerance=""/> <recipeline material="Dolomite" amount="20.000" tolerance=""/> <recipeline material="Fusion Frit F-493" amount="25.000" tolerance=""/> <recipeline material="EPK" amount="24.500" tolerance=""/> <recipeline material="Red Iron Oxide" amount="2.700" tolerance=""/> <recipeline material="Talc" amount="4.000" tolerance=""/> <recipeline material="Silica" amount="18.500" tolerance=""/> <recipeline material="Rutile" amount="2.000" added="true"/> <recipeline material="Calcined Alumina" amount="0.250" added="true"/> </recipelines> </recipe> </recipes>
Born: 2019-01-14, Modified: 2020-03-16 17:17:14
