What is Gerstley borate used for?
Gerstley Borate is a sodium-calcium-borate compound used in ceramics as a low and mid-range temperature flux. It is essentially a source of boron in glazes, and acts as a melting agent. It also can act somewhat as an opacifier and prevent crazing. It is a conglomerate mineral made up mainly of Colemanite, Ulexite and Hectorite.
Is Gerstley borate a flux?
The frit and Gerstley Borate are always fluxes, the talc is a flux under certain circumstances. Left: Worthington Clear cone 04 glaze (A) uses Gerstley Borate to supply the B 2 O 3 and CaO. Right: A substitute using Ulexite and 12% calcium carbonate (B).
Is Gerstley borate soluble in glaze?
Chemical Composition of Gerstley Borate. (PDF: 84k) This material is partially soluble and can flocculate glaze slops. It can help prevent crazing when used in small amounts, and can act somewhat as an opacifier in larger amounts, giving glazes a milky appearance.
How to replace Gerstley borate with boron?
You can use glaze calculation software to replace it with a boron frit. Gerstley is mainly silica, calcium and boron with some sodium More sharing options... Gerstley Borate is a common name for a mineral of the sodium calcium borate hydrates that ware mined in the western desert in in USA.
What can I use instead of Gerstley borate?
IMCO Borate is a blended product that is a direct substitute for Gerstley Borate. They say it "has the same physical properties as Gerstley Borate. It mixes with water to form a creamy slurry that gels and keeps the glaze from settling.
Is Gerstley borate borax?
Gerstley Borate is a sodium-calcium-borate compound used in ceramics as a low and mid-range temperature flux. It is essentially a source of boron in glazes, and acts as a melting agent. It also can act somewhat as an opacifier and prevent crazing....Gerstley Borate.Qty:Unit Price:5$3.3825$2.8250$2.54100$2.26
Is Gerstley borate a clay?
GB natural source of boron that was mined in southern California for many years. Mineralogically it is a combination of colemanite, ulexite and high plasticity clay (likely hectorite).
Where does Gerstley borate come from?
Gerstley borate is a calcium borate ore containing the mineral Ulexite ( 3CaO Na2O 5B2O3 16H2O ), along with accessory minerals such as Bentonite, Colemanite, and Probertite. Gerstley borate was formed in marshes and drying lake basins during the Miocene (10 million years ago).
Why is borax no longer used?
In fact, the U.S. Food and Drug Administration (FDA) banned borax as a food additive. Borax is not safe to ingest. According to the NLM's Toxicology Data Network, borax is easy for the body to break down when either inhaled or swallowed.
What is the difference between borax and borate?
Borax is a common name used to name sodium borate. They have different chemical and physical properties depending on their chemical composition. Borax is a mineral. It is a salt of boric acid.
What does Borax do to clay?
Borax is not typically used in clay bodies; because it is highly water-soluble, this means that it will 'travel' with the water bound up in a clay body furing the drying of a vessel, ultimately migrating to the vessel's surface and leaving behind tell-tale salt-scumming.
Are Gerstley borate and Gillespie borate the same?
In the fired state, Gillespie borate is virtually identical to Gerstley borate by virtue of the chemical match of oxide content. The special behavior of Gerstley and Gillespie borates that produces the unusual glaze effects results from two mechanisms: immiscibility and solubility.
What does wood ash do in a glaze?
A glaze that employs organic ash (e.g. paper, wood) as a supplier of oxides (e.g. silica, alumina, soda, calcia). Ashes are generally flaky and fibrous and cannot be screened well, this consistency contributes to variegation in the color and texture of the fired surface.
Why did the EU ban borax?
The EU banned borax in 2010 due to claims of impacts on reproductive health. This ban was implemented following studies on rodents who were fed high – some might say abnormally high – doses of borax. The only study I can find looking at the potential impact of borax on human reproductive health is this study.
What is borate used for?
Borate-based preservatives can be used to treat solid wood, engineered wood composites and other building materials like studs, plywood, joists and rafters. Borates prevent fungal decay and are deadly to termites, carpenter ants and roaches - but are safe for people, pets and the environment.
What is the most common use for borates?
Borax is a powdery white substance, also known as sodium borate, sodium tetraborate, or disodium tetraborate. It's widely used as a household cleaner and a booster for laundry detergent.
Does borax have another name?
Borax is a powdery white substance, also known as sodium borate, sodium tetraborate, or disodium tetraborate. It's widely used as a household cleaner and a booster for laundry detergent. It's a combination of boron, sodium, and oxygen.
What is a brand name for borax?
20 Mule Team is the best known brand of borax, which they sell primarily as a laundry detergent booster.
Is Gillespie borate the same as Gerstley borate?
In the fired state, Gillespie borate is virtually identical to Gerstley borate by virtue of the chemical match of oxide content. The special behavior of Gerstley and Gillespie borates that produces the unusual glaze effects results from two mechanisms: immiscibility and solubility.
Is Colemanite Gerstley a borate?
GERSTLEY BORATE (real) A sodium-calcium-borate compound used as a low and mid-range glaze flux. This is a conglomerate mineral made up primarily of Colemanite, Ulexite and Hectorite.
What is a Gerstley Borate?
GERSTLEY BORATE (real) A sodium-calcium-borate compound used as a low and mid-range glaze flux. This is a conglomerate mineral made up primarily of Colemanite, Ulexite and Hectorite. Gerstley is a natural borate similar to but not interchangeable with Colemanite on a 1 to 1 basis.
What was the reaction to the end of Gerstley mining?
The general reaction to the end of Gerstley mining can best be described as panic, in response to which Laguna has been forced to adopt a revised sales approach.
What is Laguna Borate?
Laguna Borate is most useful as an auxiliary melter in a high fire glaze. So when a cone 6 glaze calls for 20% GB substitute Laguna Borate one to one (or less). Major complaint Laguna Boring! It just lays there and makes a boring glaze, great if that is what you want.
What is a cadecal?
Cadycal is a calcium borate , it seems to work best when you were using GB to do something in a glaze. Use 70% of the original amount of GB in your glaze. It does things like break and create a visually uneven color.
What is zinc used for?
It is used extensively for Bristol Glazes and Crystalline Glazes.
What is domestic porcelain?
Domestic Porcelain is a blend of three American kaolins, NO ball clays, and two plasticisers to create a porcelain clay less expensive than the Grolleg bodies, a little less translucent, whiter, and a lot easier to throw.
Is Laguna Borate cheaper than Cadycal?
And guess what, the blended Laguna Borate is actually cheaper than Cadycal! CADYCAL has been discontinued.
What is Gerstley Borate?
Gerstley Borate (sold per lb.) A sodium-calcium-borate compound used as a low and mid-range glaze flux. This is a conglomerate mineral made up primarily of Colemanite, Ulexite and Hectorite. Email this page to a friend!
What is sodium-calcium-borate?
A sodium-calcium-borate compound used as a low and mid-range glaze flux. This is a conglomerate mineral made up primarily of Colemanite, Ulexite and Hectorite.
What is the chemical composition of Gillespie borate?
The exact chemical composition of Gillespie borate is proprietary to Hammill & Gillespie. Gillespie borate is a mixture of ulexite (Na2O.2CaO.5B2O3.16H2O) with various clay minerals (aluminum silicates), alkaline earth carbonates and silicates. This material contains approximately 25% B2O3, 23% CaO, 4% total alkali and 31% loss on ignition.
What are the mechanisms of glaze effects?
The special behavior of Gerstley and Gillespie borates that produces the unusual glaze effects results from two mechanisms: immiscibility and solubility . Boric oxide (B2O3), when provided to a glass as a coarse raw mineral (e.g. ulexite), is slightly immiscible with silicate glass matrices, and the differential surface energy of the molten phase drives a mass transfer process along the interface (Gibbs-Marangoni effect) that generates the characteristic variegated texture. The slight solubility of these borates also contributes to the mottled glaze surface via migration of soluble oxides, although this effect becomes exaggerated when mixed glazes are stored for long periods.
What is Gerstley borate?
Gerstley Borate has been a valuable glaze constituent for many years and is a key part of many interesting and successful glazes over a range of firing conditions. As the supply has dwindled Hammill & Gillespie's technical staff went to the lab and began experimenting. Beginning with x-ray diffraction to determine the mineral constitution of Gerstley borate and following up with other physical and chemical tests, they fully characterized the material and identified three key characteristics: extended particle size distribution including a colloid fraction, a specific and unique distribution of oxides, and a fired property that promotes a variegated color in many glaze compositions.
What is Gillespie Borate?
Description : Gillespie Borate™ is a blended borate mineral for use in glaze formulas replacing Gerstley Borate on a pound for pound basis .
What is Gerstley Borate's wide swings in chemical composition?
Gerstley borate’s wide swings in chemical composition are a factor in finding a direct substitute. It’s like trying to hit a moving target when deciding on what chemical formula to use when developing a substitute.