Project Name
Campana Clear Cone 6 Adjustment Project
Project Codenumber
UnAssigned
Notes
This project is attempting to find a middle fire clear that has a lower expansion than G3806C (one that we have been using and recommending starting in 2016). 3806C does not pass the 300F:IceWater test on P300.
This is an encouraging recipe because it contains both lithia and zinc, their powerful fluxing action coupled with low expansion give this alot of potential to take COE very low. Other tests we have done with zinc and lithia containing recipes have lost gloss while this recipe is ultra-gloss.
Campana Cone 6 Transparent Glaze
3134, Spodumene, Zinc
|
Code # G3813 |
| Materials | Amt |
|---|---|
| Spodumene | 11.000 |
| Ferro Frit 3134 | 21.000 |
| EP Kaolin | 20.000 |
| Silica | 20.000 |
| Wollastonite | 20.000 |
| Zinc Oxide | 8.000 |
Total:100.00
Auto Unity Formula
|
Si:Al: 8.7:1 6.7 3.0 |
Notes
*This is a popular fluid-melt cone 6 base recipe. We first compared it with 4 others in an effort to produce a fluid-melt, super-gloss, low-expansion transparent base. This appears to be the 20x5 recipe with Custer feldspar switched for a mix of zinc and spodumene (combining the power of lithia, zinc and boron fluxes to achieve a very low calculated thermal expansion, it does not craze on any of the bodies tested). Interestingly, because it has lots of melt fluidity it could likely accept more Al2O3 and SiO2 and yet still fire glossy (meaning the expansion could be taken still lower).
The bubble population is a concern.
Equal weights of water and powder creates about 1.47 SG. To get it to 1.45 SG thus requires more water than powder. It creates alot of bubbles in the slurry itself (from the Spodumene, wash it first to reduce these). The powder resists wetting. It responds quickly to vinegar.
We ended up choosing the Panama base over this one because of the higher bubble population in the melt and the issues that Spodumene creates with the slurry. But if you need a lower thermal expansion (the G3806C crazes on your clay body), then this one is worth trying.
Pictures
Compared with G2926B
These are 10 gram balls melted down onto a tile to demonstrate fluidity, clarity and bubbling. Left is our standard cone 6 glaze. Right: G2813. It is flowing significant more, but not as much more as some others I am testing right now. Bottom: G3813 on a Polar Ice porcelain tile. It is high glossy, not crazing out of the kiln.
G3813 16x closeup of entrained bubbles
Others also had bubbles, but there are alot here. And they are all the same size (in clouds). Although the photo does not show it clearly, hundreds of these are breaking at the surface, leaving dimples. This was fired by drop-100F-an-soak. This would do better in clearing itself with thinner application.
G3814 Low Zinc High Feldspar Fritless base melt balls
Top: G3814 G2926B Plainsman whiteware base L3808A high B2O3 fluid clear G3813 Campana clear
Fluid cone 6 clear glazes
These are 10 gram glaze balls are fired down onto tiles to demonstrate melt fluidity and bubbling. Left: L3808 GB clear from Shaun Mollonga (most fluid). G3808A fritted recalculation of former (best surface). G3813 Campana clear (most transparent). G3806B Panama Blue base. All of these survived 260F:Icewater test without crazing on M370, M390 and M340. Campana Clear is the smoothest on M340, Panama is second best.
Campana clear on Plainsman M370,340,390
These were ice water tested at 260F and did not craze. Coverage is defect free on all three clays.
Fluid cone 6 clear glaze comparison
Top are 10 gram balls melted down onto a tile to demonstrate melt fluidity and bubble populations. Second row: Plainsman M370 whiteware Third row: Plainsman M340 buff stoneware Fourth row: Plainsman M390 red stoneware Left to right: G3814 - not melting as well G2938 - Water blue base G3808 - High Gerstley Borate base G3808A - 3808 using frits instead G3813 - Campana base G3806B - Panama base
Cone 6 High Fluid Melt Transparents
The chemistry of these glazes falls outside typical cone 6 boron, soda, calcia, magnesia chemistry. Why? To achieve higher melt fluidity for a more brilliant surface and for more reactive response with colorant and variegator additions. Classified by most active fluxes they are: G3814 - Moderate zinc, no boron G2938 - High-soda+lithia+strontium G3808 - High boron+soda (Gerstley Borate based) G3808A - 3808 chemistry sourced from frits G3813 - Boron+zinc+lithia G3806B - Soda+zinc+strontium+boron (mixed oxide effect)
Compare four clear bases for copper blue
Has extenal picture also
The flow testers at the back and the melt-down-balls in from of them have 1% copper carbonate. The glazed samples in the front row have 2% copper carbonate. L3806B, an improvement on the Panama Blue recipe, has the best color and the best compromize of flow and bubble clearing ability.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Campana Cone 6 Transparent Glaze" keywords="3134, Spodumene, Zinc" id="75226" key="SuWbGcvh" date="2018-03-19" codenum="G3813" email="strawdogs@hotmail.com"> <recipelines> <recipeline material="Spodumene" amount="11.000"/> <recipeline material="Ferro Frit 3134" amount="21.000"/> <recipeline material="EP Kaolin" amount="20.000"/> <recipeline material="Silica" amount="20.000"/> <recipeline material="Wollastonite" amount="20.000"/> <recipeline material="Zinc Oxide" amount="8.000"/> </recipelines> </recipe> </recipes>
Born: 2015-06-23, Modified: 2018-03-19 15:58:30
Campana Clear Lower Expansion #2
3134, Spodumene, Zinc
|
Code # G3813B |
| Materials | Amt | |
|---|---|---|
| Spodumene | 11.000 | 10.00% |
| Ferro Frit 3134 | 21.000 | 19.09% |
| EP Kaolin | 20.000 | 18.18% |
| Silica | 30.000 | 27.27% |
| Wollastonite | 20.000 | 18.18% |
| Zinc Oxide | 8.000 | 7.27% |
Total:110.00
Auto Unity Formula
|
Si:Al: 10.3:1 6.4 2.7 |
Notes
*This recipe is the product of an ongoing search to find cone 6 low expansion ultra glossy clear glazes. P300 is the most difficult cone 6 body we have at Plainsman for fitting glazes. Our standard G2926B will fire uncrazed, but the combination fails a 300F:IceWater test (the way we evaluate long term resistance to crazing). Our G3806C recipe does the same. This recipe survives the test.
This recipe is a descendent of the well-known Campana Transparent. A first test was too aggressive in adding SiO2 and Al2O3 (G3813A), while it survives the 300F:Icewater test, gloss was lost. This trial adds less Al2O3 and SiO2.
It melts really well. It also survives 300F:Ice test.
However, this has tiny bubbles and surface dimples. A first drop-and-soak is not removing them all. Must experiment with firing schedules soaking lower. Will also try sourcing the Li2O from Fusion Frit 493.
Pictures
G3813B Campana Clear mugs
Fires super glossy, looks good. But there are entrained bubbles (top) vs. no bubbles in 2926B one below.
2926B vs G3813B clear glaze melt balls
Crazing on the inside upper of P300 mug after a week
This did not happen on P6476 Pioneer P300.
G2926B vs G3813 B, C, D
B top right, C - bottom left, D - bottom right. The added silica and MgO in the D make it appear more opaque yet on a mug it is crystal clear. D is moving toward the appearance of 2926B Whiteware (top left) but is still more fluid. Perhaps it could host a reactive result like floating blue.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Campana Clear Lower Expansion #2" keywords="3134, Spodumene, Zinc" id="95906" key="KSX3RnLG" date="2016-11-19" codenum="G3813B" email="strawdogs@hotmail.com"> <recipelines> <recipeline material="Spodumene" amount="11.000"/> <recipeline material="Ferro Frit 3134" amount="21.000"/> <recipeline material="EP Kaolin" amount="20.000"/> <recipeline material="Silica" amount="30.000"/> <recipeline material="Wollastonite" amount="20.000"/> <recipeline material="Zinc Oxide" amount="8.000"/> </recipelines> </recipe> </recipes>
Born: 2015-06-23, Modified: 2016-11-19 11:26:15
Campana Clear Low Expansion (no Spodumene)
3134, Spodumene, Zinc
|
Code # G3813C |
| Materials | Amt | |
|---|---|---|
| Fusion Frit F-493 | 9.000 | 7.35% |
| Ferro Frit 3195 | 18.000 | 14.69% |
| EP Kaolin | 25.000 | 20.41% |
| Silica | 34.500 | 28.16% |
| Wollastonite | 27.000 | 22.04% |
| Zinc Oxide | 9.000 | 7.35% |
Total:122.50
Auto Unity Formula
|
Si:Al: 10.3:1 6.5 3.0 |
Notes
*This sources Li2O from a Fusion Frit instead of Spodumene. This is a strategy to remove the micro-bubbles in the fired glass (and tiny dimples on the surface).
Used 800 water for 1000 dry to give about 1.48 SG.
It is very glossy where thin. Where thicker is has enough bubbles that the surface mattes. Needs more firing to see for sure.
Survives 300F:Icewater test.
Pictures
G3813C Campana Clear Low Expansion (no Spodumene)
G2926B vs G3813 B, C, D
B top right, C - bottom left, D - bottom right. The added silica and MgO in the D make it appear more opaque yet on a mug it is crystal clear. D is moving toward the appearance of 2926B Whiteware (top left) but is still more fluid. Perhaps it could host a reactive result like floating blue.
G3813C glaze on inside of P300 mug
Bottom is a little matte, as well as sides (because of clouds of micro bubbles). Just below the rim it is glossy. Survives 300F:Icewater test.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Campana Clear Low Expansion (no Spodumene)" keywords="3134, Spodumene, Zinc" id="99421" key="1eBXpCDR" date="2016-12-02" codenum="G3813C" email="strawdogs@hotmail.com"> <recipelines> <recipeline material="Fusion Frit F-493" amount="9.000"/> <recipeline material="Ferro Frit 3195" amount="18.000"/> <recipeline material="EP Kaolin" amount="25.000"/> <recipeline material="Silica" amount="34.500"/> <recipeline material="Wollastonite" amount="27.000"/> <recipeline material="Zinc Oxide" amount="9.000"/> </recipelines> </recipe> </recipes>
Born: 2015-06-23, Modified: 2016-12-02 11:48:21
