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Fusion Frit F-19 is said to be a substitute for Ferro Frit 3124, for this particular glaze that appears to be true. The Arbuckle Majolica glaze was applied on Plainsman L210 and fired at cone 04 (but not as thickly applied as would be customary on Majolica ware). On the left is the one with Ferro Frit 3124, on the right is the one with the F-19. The recipe is based on Ferro Frit 3124 and adds 20% of a feldspar neheline mix (likely to increase thermal expansion because it shivered on the original clay body). It is suspended by 10% kaolin. This may craze on your clay body, the G1916Q thermal expansion adjustable transparent base might be a better solution (it responds similarly to a zircon/tin addition to opacify).
Tin oxide is a powerful opacifier, but the 5% in this Frit 3124 based Arbuckle Majolica cone 04 recipe on the left is not sufficient. Adding 10% zircon (e.g. Zircopax, Superpax) produces the one on the right. Would just using 15% zircon be better? No. More zircon means a stiffer melt and more issues with crawling (notice the small bare spots on the right edge). This could be managed by the addition of CMC gum or a higher clay content to get better adhesion and dry hardness). But another improvement would be worth trying first: Use 4% tin and 8% zircon. That should opacify enough and present fewer problems with crawling.
The mug on the left has three coats of Spectrum Majolica base, painted on by brush. Drying was required after doing the inside coats, so the total glazing time was several hours. The glaze layer is way too thin and it is not even at all! The one on the right was dipped in a 5 gallon bucket-full of G3890 Arbuckle white (that was weighed out according to a recipe and slurried at 1.62 specific gravity). It took seconds to dip-apply, the thickness coverage is good. As is obvious, it makes sense to make your own base white. Then decorate using the overglaze colors (e.g. the Spectrum Majolica series). Another advantage of making your own white is that you can splurge on the amount of opacifier (in this case 9% zircon and 4% tin oxide), to achieve maximum whiteness and opacity. And, you can proportion a mix of two frits (having higher and lower thermal expansion) to fine-tune the fit with the body (a big issue at low fire).
Glossary |
Majolica
Majolica is white opaque glazed red earthenware clay having colored overglaze decoration. But if you know more about what it is technically you will have more control of your product. |
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Glossary |
Material Substitution
Material substitutions in ceramic glaze and body recipes must consider their chemistry, mineralogy and physical properties |
Materials |
Fusion Frit F-19
A commonly available calcium borosilicate frit having a similar chemistry to Ferro Frit 3124. |
URLs |
https://glazy.org/recipes/11469
Linda Arbuckle Majolica glaze recipe |
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