Leach's Satin Clear Original
|
Code # G2941A |
| Materials | Amt |
|---|---|
| Custer Feldspar | 21.700 |
| Whiting | 21.700 |
| Silica | 21.700 |
| EPK | 21.700 |
| Ferro Frit 3124 | 13.200 |
Total:100.00
Auto Unity Formula
|
Si:Al: 7.0:1 7.2 (Molar:7.1) 12.8 Cost 0.48 per kg |
Notes
This is crazing on Laguna B-mix. Neither the clay or glaze are at fault, they are simply incompatible. Still, 20% feldspar sourcing lots of KNaO plus extra KNaO coming from a frit certainly makes crazing less than a surprise for this glaze.
Concerns: It is melting enough, but has low B2O3 and it won't take much to introduce cutlery marking and leaching.
Since this is a silky matte, it will be able to accept low-expansion MgO and can afford to give up high expansion KNaO. MgO is a mechanism for matte glazes.
It might be wise to consider using the base matte at http://plainsmanclays.com/index.php?menupath=62
It can be tuned by adding glossy glaze, giving alot of control over the degree of matteness. Matteness is a fragile mechanism that needs close control and assure a compromise between functionality and appearance.
Another matte base option is G1214Z. It is a calcium matte base that is well documented on the internet (just google "G1214Z recipe".
Pictures
Leaches clear on BMix - Crazing
URLs
A good adjustable base matte recipe
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Leach&#039;s Satin Clear Original" id="61955" key="ecauBL67" date="2019-05-31" codenum="G2941A" email="j_johnsrud@hotmail.com"> <recipelines> <recipeline material="Custer Feldspar" amount="21.700" tolerance=""/> <recipeline material="Whiting" amount="21.700" tolerance=""/> <recipeline material="Silica" amount="21.700" tolerance=""/> <recipeline material="EPK" amount="21.700" tolerance=""/> <recipeline material="Ferro Frit 3124" amount="13.200" tolerance=""/> </recipelines> </recipe> </recipes>
Born: 2014-10-14, Modified: 2019-05-31 12:14:43
Leach's Satin Clear - Craze fix
|
Code # G2941C |
| Materials | Amt |
|---|---|
| Custer Feldspar | 21.485 |
| Whiting | 21.485 |
| Silica | 22.475 |
| EPK | 21.485 |
| Ferro Frit 3124 | 5.149 |
| Ferro Frit 3249 | 7.921 |
Total:100.00
Auto Unity Formula
|
Si:Al: 6.8:1 6.8 (Molar:6.6) 12.7 Cost 0.48 per kg |
Notes
This recipe is the product of tweaking in my Insight-live.com account. My objective was to introduce MgO (very low thermal expansion oxide) at the expense of KNaO (very high expansion).
I originally tried supplying MgO from Talc. But in this recipe I employed Ferro Frit 3249, it is a much better because it has zero-LOI, is more consistent, melts better and brings more B2O3 (that extra B2O3 is going to make the glaze melt better). Frit 3249 is a super-low expansion frit. Only small changes were needed to match up oxide levels disrupted by its introduction. The fired result looks identical on the flow tester. But if it is a little too glossy, Al2O3 levels can be raised to tune it (that would by easy in Insight-live, just lower the EPK until the calculated Al2O3 hits 0.50, then raise the SiO2 to bring it back up to 2.95).
Another helpful change that could be made is sourcing CaO using Wollastonite instead of calcium carbonate. That would really lower the LOI.
Pictures
Leach's Clear crazing adjustment
This substitutes MgO for some of the CaO and KNaO. It also adds a little more B2O3 for better melting. This melts just as good or better and appears to have about the same surface gloss. It would be a little more matte by raising the Al2O3, this would drive the expansion down even further.
Leach's clear and craze adjustment
3mm thick x 15mm square samples fired on a porcelain tile.
Left: Original
Right: Adjustment.
The surface is iddentical on this samples.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Leach&#039;s Satin Clear - Craze fix" id="61966" key="GwoWh6gG" date="2019-05-31" codenum="G2941C" email="j_johnsrud@hotmail.com"> <recipelines> <recipeline material="Custer Feldspar" amount="21.485" tolerance=""/> <recipeline material="Whiting" amount="21.485" tolerance=""/> <recipeline material="Silica" amount="22.475" tolerance=""/> <recipeline material="EPK" amount="21.485" tolerance=""/> <recipeline material="Ferro Frit 3124" amount="5.149" tolerance=""/> <recipeline material="Ferro Frit 3249" amount="7.921" tolerance=""/> </recipelines> </recipe> </recipes>
Born: 2014-10-16, Modified: 2019-05-31 12:12:23
