Randy's Red Original Cone 6 Glaze
|
Code # G2890B |
Batch # -2 |
| P | Materials | Amt | |
|---|---|---|---|
| Gerstley Borate | 31.700 | 31.67% | |
| F-4 Feldspar | 19.800 | 19.78% | |
| Talc | 13.900 | 13.89% | |
| EPK | 5.000 | 5.00% | |
| Silica | 29.700 | 29.67% |
| P | Additions | ||
|---|---|---|---|
| Bentonite | 2.000 | 2.00% | |
| * | Red Iron Oxide | 15.000 | 14.99% |
Total:117.10
Auto Unity Formula
|
Si:Al: 15.7:1 5.8 (Molar:5.7) 11.0 Cost 0.06 per kg |
Notes
The most widely known iron red recipe. But it is also one of the most widely hated. The combination of Gerstley Borate and high iron turns the slurry into super-jelly. Thinning it with water just gels again. It also shrinks and cracks on drying and crawls on firing. People endure it in a quest to get the red it can produce.
This recipe may have a new life since the above problems are eliminated or much less when using Gillespie Borate.
Pictures
Example of a picture search of Randy's Red on google
All of these people suffer using this!
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Randy&#039;s Red Original Cone 6 Glaze" id="36586" key="PLMy14uj" date="2024-02-16" codenum="G2890B"> <recipelines> <recipeline material="Gerstley Borate" amount="31.700" tolerance=""/> <recipeline material="F-4 Feldspar" amount="19.800" tolerance=""/> <recipeline material="Talc" amount="13.900" tolerance=""/> <recipeline material="EPK" amount="5.000" tolerance=""/> <recipeline material="Silica" amount="29.700" tolerance=""/> <recipeline material="Bentonite" amount="2.000" added="true"/> <recipeline material="Red Iron Oxide" amount="15.000" added="true"/> </recipelines> </recipe> </recipes>
Born: 2012-11-04, Modified: 2024-02-16 17:29:50
Red Orange Glazy Original
|
Code # G3948 |
Batch # -2 |
| P | Materials | Amt |
|---|---|---|
| Minspar 200 | 36.700 | |
| Silica | 12.800 | |
| EPK | 12.900 | |
| Talc | 13.800 | |
| Tricalcium Phosphate | 12.100 | |
| Ferro Frit 3124 | 7.500 | |
| Lithium Carbonate | 4.100 |
| P | Additions | |
|---|---|---|
| * | Red Iron Oxide | 11.500 |
Total:111.40
Auto Unity Formula
|
Si:Al: 7.9:1 6.2 (Molar:6.2) 5.1 Cost 0.15 per kg |
Notes
From https://glazy.org/recipes/111576
We immediately noted from testing that this gives a better iron red than Randy's Red.
Touted as a reliable iron red. This achieves its high melt mobility with low SiO2 and lithium whereas Randys Red does it with high B2O3. This one sources CaO from TCP, which seems to act as a catalyst for the formation of the crystals.
Crocus Martis is often used as the source of iron in this recipe, but since most people do not have it they use red iron. That is a big problem, this much iron creates glazes that are "buckets of jelly!" That being said, in our recent experience with this recipe no gelling has been noted, it appears the very fine lithium carbonate powder is deflocculating the slurry.
We immediately saw things that could be improved:
-Source Li2O from Spodumene.
-Use black iron so the slurry does not gel.
-Source Na2O from Frit 3110 to enable sourcing Al2O3 and SiO2 from the spodumene and kaolin instead feldspar.
-Use Frit 3134 instead of 3124, it contributes less Al2O3, that should come from kaolin instead.
We calculated an adjustment, G3948A.
Pictures
G3948 Red Orange Glazy Original
On M390 fired at cone 6 using the C6DHSC schedule.
G3948 Red Orange Original vs PC-56
Left: Amaco PC-56 Ancient copper (more thickly applied)
Right: G3948 iron red
Firing schedule for both is C6DHSC.
Clay is M390.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Red Orange Glazy Original" id="217984" key="hBAqY6Hp" date="2023-11-06" codenum="G3948" email="jrspiteri@comcast.net"> <recipelines> <recipeline material="Minspar 200" amount="36.700" tolerance=""/> <recipeline material="Silica" amount="12.800" tolerance=""/> <recipeline material="EPK" amount="12.900" tolerance=""/> <recipeline material="Talc" amount="13.800" tolerance=""/> <recipeline material="Tricalcium Phosphate" amount="12.100" tolerance=""/> <recipeline material="Ferro Frit 3124" amount="7.500" tolerance=""/> <recipeline material="Lithium Carbonate" amount="4.100" tolerance=""/> <recipeline material="Red Iron Oxide" amount="11.500" added="true"/> </recipelines> </recipe> </recipes>
Born: 2022-06-21, Modified: 2023-11-06 04:17:14
Iron Red Orange
|
Code # G3948A |
Batch # -2 |
| Materials | Amt | |
|---|---|---|
| Ferro Frit 3110 | 20.500 | 20.48% |
| Silica 325 mesh (Silica) | 10.200 | 10.19% |
| EPK | 15.800 | 15.78% |
| Silverline 303 Talc | 13.800 | 13.79% |
| Tricalcium Phosphate | 11.300 | 11.29% |
| Ferro Frit 3134 | 7.000 | 6.99% |
| Spodumene | 21.500 | 21.48% |
| Additions | ||
|---|---|---|
| Black Iron Oxide | 11.200 | 11.19% |
Total:111.30
Auto Unity Formula
|
Si:Al: 7.6:1 6.5 (Molar:6.4) 3.9 Cost 0.68 per kg |
Notes
This fires like Amaco PC-56 Ancient Copper. It is an "iron red". Recipes in use are very problematic (erratic firing, excessive running, gelling in the bucket).
I mix 80:100 water:powder to get a thixotropic slurry (it might be different for you depending on the electrolytes in your water). It does not gel like what happens when using red iron oxide. And application properties are very good.
Initial fired results on all bodies tried were very good using the C6IRED schedule. Later I found the C6DHSC worked well also.
Good control of the slurry rheology is important so that each time you use the glaze is applies as the same thickness for a given immersion time. This is because the thickness of application is the key to the visual effect this produces. Its melt fluidity is high (it is runny), yet a thick application is needed to achieve the visual effect. That means a catch glaze on the outsides of ware is required (this glaze itself can be the catcher if applied thinly). Allowing pooling on the insides of pieces is not advisable; it can produce glaze compression which will cause cracking at a later time.
Some of the pictures do not convey the red color as well as others. This gives much better iron red coloration on dark-burning bodies like M390 or Coffee Clay.
Durability: This could be an issue because of the relatively low Al2O3 and SiO2 (their low levels are the mechanism of the fluid melt - this could fail a vinegar leaching test). I tried using the G3806E base recipe; its thermal expansion is lower, but the iron crystals do not develop (it later became evident the problem was with the chemistry of that base).
Crazing: The thermal expansion calculates fairly low despite low SiO2 and Al2O3, but crazing is still possible. Using 325 mesh silica is important.
A lithium carbonate version of this is also possible (would require chemistry).
Pictures
G3948A on Coffee Clay
Fired using the C6DHSC schedule and the catch glaze technique for application.
G3948A Red Orange Iron Red mugs
Done using our standard C6DHSC slow cool schedule. This in M370.
G3948A Red Orange Iron Red on dark body
The mug on the righty is M390, left is M340.
G3948A Iron Red on Coffee Clay and Polar Ice
C6DHSC schedule
G3948A Iron Red glaze on Polar Ice and M370
Fired at cone 6 using the C6IRED schedule.
Glaze was applied double thickness on the top half of the samples. Clearly this has a high melt fluidity.
G3948A - special iron red firing schedule vs normal slow cool
C6IRED vs. C6DHSC firing schedules.
The latter is working much better.
G3948A vs Amaco PC-56 at cone 6
Using the PLC6DS firing schedule.
G3948A, G3948A and Amaco PC-56
Fired cone 6 using the C6DHSC slow cool firing schedule.
Top left: G3948, the original recipe found at Glazy
Top right: G3948A, our adjustments
Bottom: Amaco PC-56 Ancient Copper
The PC-56 is firing more matte and more heavily crystallized. If you want that then add more iron to the G3948A recipe.
G3948A on M390, M340
C6DHSC firing schedule.
This glaze seems to produce great results on almost any clay!
Of course, if applied thickly on ware a catch glaze will be needed at the bottom to stop overflow.
G3948A vs Amaco PC-56 melt flow
Fired at cone 6 drop and hold.
PC-56 has a slightly greater melt fluidity (suggesting a little more lithium or boron). It is crystalizing, indicating more iron oxide (in my opinion a little too much).
G3948A closeup
G3948A Iron Red to cone 6, 5, 4 on Coffee Clay
They were fired at cone 6, 5 and 4 using the C6DHSC schedule (adjusted for top temperature).
Iron Red gone wrong?
Mar 2023: We mixed the recipe multiple times and kept getting this. The problem turned out to be filling our TCP jar with the wrong material, likely Pyrophylite.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Iron Red Orange" id="218094" key="c6CnEZRR" date="2026-06-14" codenum="G3948A" email="jrspiteri@comcast.net"> <recipelines> <recipeline material="Ferro Frit 3110" amount="20.500" tolerance=""/> <recipeline material="Silica 325 mesh" lookup="Silica" amount="10.200" tolerance=""/> <recipeline material="EPK" amount="15.800" tolerance=""/> <recipeline material="Silverline 303 Talc" amount="13.800" tolerance=""/> <recipeline material="Tricalcium Phosphate" amount="11.300" tolerance=""/> <recipeline material="Ferro Frit 3134" amount="7.000" tolerance=""/> <recipeline material="Spodumene" amount="21.500" tolerance=""/> <recipeline material="Black Iron Oxide" amount="11.200" added="true"/> </recipelines> </recipe> </recipes>
Born: 2022-06-21, Modified: 2026-06-14 15:03:30
