True Cone 10 Zinc Crystal glazes have fascinated potters for the last hundred years. One major advance, digital controllers, put Crystal glazes in reach of any potter. In this short article, I will outline the basics and give some recipes.
Clay: use a smooth, white clay for cone 10; such as New Mexico Clay' s Domestic, CK-mix, or any cone 10 porcelain. Try making plates or tiles at first, as crystal glazes are VERY runny*. If you wish to make a vase you must throw a little dish to fire your pot on; after bisquing, glue the dish and the vase together with alumina hydrate.
The glaze: After trying many different glazes, I recommend one based on Ferro Frit 3110. Herbert Sanders book on Glazes for Special Effects (sadly, out of print) lists this as Glaze #3.
Notice that this glaze is very high in Zinc and contains no Alumina. The excessive amount of Zinc crystallizes into Zinc Orthosilicate crystals in the glaze, the same way sugar when super saturated in water will turn into rock candy. Low alumina allows the necessary fluidity* that the crystals need to be able to grow.
For color add these oxides to base glaze:
Cobalt Carbonate .75% to 1% for dark blue crystals with a lighter background.
Iron Oxide 4% for brown crystals.
Nickel Oxide Green 4% for blue green crystals on brown background.
Manganese Dioxide 1% to 4% for lavender on tan.
Uranium Oxide 6% to 10% for yellows and golds.
Praseodymium Oxide for white with yellow edges.
Apply the glaze by spraying onto bisque, as it contains no clay and is horrible to brush on. Try layering the glazes, as opposed to mixing the oxides, for interesting varied colors.
Firing: In general fire to cone 10, cool the kiln to 2000 degrees and hold for 3 to 5 hours in-between 2000 and 1800 degrees.
With a digital kiln a firing would go like this:
Ramp 1: rate 250°, to 1000° no hold.
Ramp 2: rate 500°, to 2320° hold 15 minutes. (00.15)
Ramp 3: rate 500° (to 9999 to cool faster), to 2000° hold for 03.00 hours.
Ramp 4: rate 500°, to 1800° hold for 01.00 hours.
Let cool, no peeking!
*These glazes are very runny. A catch plate is a base you throw that matches the bottom of the pot, it is then glued onto the bottom of the pot with a mixture of alumina hydrate and elmers glue. After firing the catch plate is removed and the bottom is ground to a nice finish. That is why I just made plates and bowls, not vases.
The Sandia Mountains - Plate by Brant Palley Cone 10 crystal glazes 1988
Make parts one day assemble the creature on another day.
Make a bowl
Learn to work the paperclay way of attaching dry to dry with a slip and some clay.
Sheepdog fiberclay that doesn't rot.
WHITE EARTHENWARE WLO: A smooth white clay. Our most popular clay with schools and teachers. Excellent for all types of modeling projects. Compatible with all commercial glazes.
We go to great effort to make this clay smooth.
WHITE EARTHENWARE WITH SAND: A very smooth body better for kids work than the WLO Same as above but added fine white sand provides strength for larger forms. Compatible with all commercial glazes
SHEEPDOG lowfire earthenware with fiber, our version of that Papered Clay! Our fiber doesn't rot, and will fit most commercial glazes. lowfire sculptural body 04-06. It contains 5% fine white sand and our superfine nylon fiber.
TAXIDERMY Non firing, air dry clay with fiber. Will adhere to armatures, let dry, cover or paint.
SHEL’S Outdoor sculpture body has an absorption rate of .3 % at cone 02. Great for colorful outdoor sculpture.
W.E.S. White earthenware for sculpture: Finally a low fire white clay for sculpture that fits all Duncan and Mayco Glazes.
STORYTELLER (APSW): A light tan to pink colored earthenware . An excellent plastic throwing body. Compatible with all commercial glazes.
RED EARTHENWARE RL6: A smooth red clay. Perfect for hand building. Fires from an orange at Cone 016 to a red at cone 06 to a brown at 02. Beautiful when burnished.
APS RED: Similar to RL6 in color, but with the addition of 90 mesh sand, this clay body is more rugged and better suited for wheel work. Perfect for functional ware.
JONIES CLAY: Same as APS Red with 5% grog for working larger.
MANZANO : Manzano Red clay is one of the first real N.M. Clays. It is mined from the Manzano Mountain area, it is then ground and airfloated. The Manzano clay body also contains 10% fine sand from Placitas, the sand has been screened and washed. There is some talc, from south of El Paso Texas, to help with glaze fit. And 1% Mica for pretty. Unfired clay is green color
MICA WHITE AND MICA RED Two new clays similar to Indian pottery from around New Mexico, Mica historically was mined near Taos. Can be glazed if bisqued to 04. Burnish and fire to cone 010.
RAKU 2000*: A rough white clay body designed to take the rigorous handling of Raku firing. This body throws well and is perfect for large sculpture or slab work. Contains Kyanite and grog. For best results bisque to 08
CLEANOUT CLAY: White or Red , we don’t know what is in it exactly, but they are fine for most kid’s projects. If you try some and like it better buy the whole ton.
PECOS PORCELAIN: NEW formula- True porcelain with good plasticity suitable for throwing SMALL useful and serviceable tableware. It has good translucency at cone 6 and is great for wind chimes or jewelry.
CASHMERE: A smooth throwable porcelain. New Mexico Clay's version of all those B-Mixes out there. Same body as Cashmere slip.
MAGIC CLAY A new product from New Mexico Clay, Magic Clay is a fibered Cone 6 smooth, plastic, porcelaneous body. The fiber is extremely fine and burns out in the firing. Works like paper clay but doesn’t rot.
COLUMBINE: A cream white clay that is easy to throw and form. Excellent glaze results. Smooth porcelain texture contains extremely fine sand you can’t feel. Pugged soft.
WHITE STONEWARE WH8: midrange white stoneware with 10% sand. An excellent plastic throwing body.
WHITE STONEWARE ROUGH WH-Rough for tile . A Tile clay that your glazes will not craze on.
OCHRE: A plastic throwing body, also good for small sculpture and hand-building. Based on goldart stoneware clay, adapted from a Richard Zakin formula.
SUPER SCULPT 2000!: New buff sculpting clay, not too rough but toothy, contains pyrophillite for excellent strength and has a wide firing temp from 5-10, even stands up to wood firing at cone 11.
ANASAZI 5: Cone 5 version of original cone 10 ANASAZI it is an outstanding, all purpose, medium texture, moist clay. Durable and affordable, good for professional or student. Reduces a warm orange/brown, light tan to yellow in oxidation.
ANASAZI 5X same as above however the addition of a larger amount of red clay gives it a warm brown color.
SANDIA RED : Semi smooth red body with sand. Fires paver tile red in oxidation at cone 5, more chocolate in reduction
MARILYN’S BOD. A red brown stoneware excellent for throwing and functional ware.
TERRA-COTTA TC: Similar to red Earthenware in color at 04* but lighter, chocolate brown at cone 5, with good quality grog and fire clay, this clay body is more rugged and better suited to large sculptural pieces. Cone 04-5.
RED SCULPTURE: A sculpture, tile and throwing body, very plastic that fires red-er at cone 5 to red-brown at cone 6. Can be used for sculpture at cone 04. Glazes will fit this clay at cone 6.
ChoCoLate: A Dark Hershey brown smooth clay, almost black, glazes look cool and fit! Best results fire medium speed to cone 5 and hold for 10 min.
* Glazes will craze at normal firing temp. Not food safe.
Vase By Gary Parker
Clay, High Fire Cone 10
SRUBEK: All Grolleg kaolin NO ball clay. 2-5 formula. Genuine Japanese style porcelain translucent and white.
DOMESTIC: A new NO ball clay porcelain, Throws great, has a nice white color and fair translucency. White as the grolleg porcelains, but is 30% cheaper and throws way better! We used 3 kaolins and 2 plasticizers to create this new body. Best for crystal glazes.
CK-MIX : A cream white clay that is easy to throw and form. Excellent glaze results. Fires off white in reduction lighter in oxidation. Smooth porcelain texture. Our version of B-mix
CK-MIX WITH PURE SILICA SAND: This is a nice cone ten white stoneware, perfect for dinnerware. Throws great, feels smooth before and after it is fired. Fires a pleasing white to gray. Will show off bright glaze colors.
Stoneware Clays Cone 10
NMSOL: All California fireclays give this versatile clay body a pleasing sunny California toasty warm color in reduction. Our sand doesn’t pop out giving the body a smooth texture after firing.
HIGH HILLS II: Our version of the popular Missouri fireclay, Goldart, ball clay and grog type stoneware. Very forgiving and throwable clay for production potteries. Tan to gray brown in reduction, medium texture. Jeff Zamik approved body
STILLETO: High Hills with no extra iron so it has a slightly lighter look.
ANASAZI 10: An all purpose orange brown to yellow firing clay. Anasazi has a beautiful color whether fired in an electric kiln or gas, did great in the Anagama kiln, with no sign of bloating, and beautiful flashing form the flame. DON’T OVER REDUCE!!!
SUPER SCULPT 2000!: Buff sculpting clay, not too rough but toothy, contains pyrophyllite for excellent strength and has a wide firing temp from 5-10, even stands up to wood firing at cone 11.
ANN’S SODA AND WOOD FIRED WHITE STONEWARE: Our Cone 10 soda and flashing body contains 2 Kaolins (Helmers is one) for whiteness, and stoneware and sagger clays for flashing, also has 10% fine grog. A creamy color in oxidation, a grey color in light reduction.
Laguna Clay Pugged clays
B-MIX CONE 5: A smooth cream-white colored throwable porcelain
Frost Porcelain: Finally a white translucent porcelain for cone 6, looks amazing and is expensive.
AMADOR-5X: Cone 6 version of original cone 10 AMADOR with extra iron. 5X is an outstanding, all purpose, orange brown, moist clay. Durable and affordable, good for professional or student. Reduces a warm orange/brown, light chocolate in oxidation.
SPECKLED BUFF a buff clay with pronounced speckles that bleed into a glaze. Smooth texture.
S-B RED: Medium texture bright red body with sand and grog. Fires paver tile red in oxidation at cone 5, more chocolate in reduction
B-3 BROWN: A pliable BLACK clay with smooth grog and color from Manganese and Iron. Fires black when reduced, and a pretty good black in oxidation.
WESTSTONE II: Excellent general purpose clay, Slightly coarse texture, yellow-brown in oxidation, warm brown in reduction.
SANTA FE: Medium coarse, excellent throwing body a golden tan adobe color.
WS-5: A gray white body with 70 mesh sand. Fires a textured gray/white in reduction and a buff/white mottled surface in oxidation. Care should be taken when used for functional ware, not vitrified in most cone 5* firings. Glazes may craze. Can be fired to cone 10.
SOLDATE 60: Soldate 60 is a gray clay with a high sand content and is pugged firm which makes it an ideal choice for large thrown pieces and sculptural forms. Fires to a yellow brown under medium reduction, it has a coarse texture.
AMADOR: Is an inexpensive, all purpose, orange brown, moist clay. Durable and affordable, good for professional or student. Reduces a warm orange/brown, lighter in oxidation.
LB BLEND: Long Beach Blend is an excellent, very fluid throwing clay, which is also extremely popular for throwing open forms, small to large. It is brownish pink in its raw form, light brown reduced and buff in oxidation. Includes iron and 60 mesh sand
B-MIX : A cream white clay that is easy to throw and form. Excellent glaze results. Fires off white in reduction lighter in oxidation. Smooth porcelain texture.
B-MIX W / SAND with 10% 90 mesh sand for texture and speckle.
FROST PORCELAIN 10: Finally a white translucent porcelain from New Zealand kaolin, looks amazing and is expensive. Imported. Cone 10
COLEMAN porcelain from Aardvark, Cone 10, The whitest most translucent formula possible, NO ball clay, contains new secret plasticizer
We will custom blend your own clay body, (Or one of our clays harder or softer, smoother or rougher) at no extra charge. One ton Minimum. (1000 lbs minimum when we are making that clay.) Allow 6 weeks time. Try to use the raw materials we stock when formulating a custom clay body, some east coast ingredients or older recipes are not available.
All Skutt kilns with KilnMaster Controllers are programmed to generate Error Codes when something goes wrong during a firing. These not only give you an indication of what the problem may be, they also often will shutdown the firing to protect your ware or the kiln itself. When an Error Code is generated it will appear in the display and, depending on your controllers age and the code, trigger the alarm. On older units it is important to make note of the code before you press any key to stop the alarm and clear the code. On newer boards you can go to the Diagnostic Menu and access the ERTF feature to see the last Error Code to occur along with the temperature it occurred at, the amount of time into the firing at which it occurred, and in addition it will run a full Diagnostic test.
Information about the use of ceramic overglazes and lusters or third fired colors.
Paint with precious metals like gold, and platinum! Apply over fired glaze to add brilliant accents that’ll make your project look like a billion bucks!
Metallic Overglazes for the brilliance of gold and white gold, and lusters for a rainbow of hues like the pearl of an oyster shell.
Overglazes are an accent product that are applied over a fired glaze and then kiln fired to a relatively low temperature. They are sometimes referred to as "third fire" glazes.
Mother of Pearl is a luster, an overglaze; it is applied over a shiny fired glaze of any color. (Copper glazes should not be used). Any natural hair brush will work, it should be clean. Apply MOP in swirls, just one thin coat. You want to see brushstrokes; they will be the swirls in the finished piece. Fire to cone 020.
Buy a dozen bottles of Duncan Gold and get 40% discount!
Discount will show in the cart good on Duncan Brand Lusters, Mother of Pearl and essence.
Our new super white, scary translucent cone 6 porcelain slip, made from a clay from New Zealand called a halloysite. It is great for nightlights, and other small objects that benefit from translucency and whiteness.
Formula includes ingredients from, Canada, Kentucky, New Zealand, Oklahoma and Wyoming! Made here in New Mexico
16.6 % shrinkage 0% absorption
What is old is now new! The 5 thousand year old process of finishing the inside walls of your home by smearing clay on the walls is enjoying a new renaissance. The idea is simple the natural materials used: mud, sand, straw, are free of the more than thousands of chemicals that can be used in conventional paints; many of which are newly created chemical components with little research conducted regarding their long-term effects on both humans and the environment.
You use your own clay, sand, and straw to begin the process of finishing your walls. Wall surfaces should not be previously painted, straw bales, adobes, even sheetrock is okay (paint the drywall first with a mix of 10 parts hydrated or homemade wheat paste, 1 part fine sand and 1 part clay. Let it dry and don't wet it down before you plaster it. The mix varies with the look you want, change the smoothness or texture and color. Start with a rougher mix and then use a smoother mix for the finish coat.
The Rough Mix:  Earth plaster (still wet) clay is Hawthorne Bond 35
1.5 parts water
2.5 parts sifted clay soil (or a mix of your soil and our clay like Hawthorne 35)
1.25 parts sand
2 to 3 parts (3/4 inch) chopped straw
Apply the rough mix with a trowel, not too thick, smooth it out with the trowel, allow to get leather hard. Then polish it with the edge of the trowel for a finished look. If you intend to finish with a smoother coat, go back with a large wet sponge and expose the grain of the sand.
The rough mix is what the Landers use as a final mix when they are doing a high straw content wall with the exposed straw look. The really rough mix would have much longer length straw, up to full length. Also the 2.5 parts sifted clay soil proportion was worked out by the Steen's for the Lander's particular soil in Kingston which they believe is about a 30 percent clay content so people at home need to experiment with their soils or if buying bagged materials work out their own recipe
Color chart of unfired clay colors
The final coat or finish coat is a much finer mixture of kaolin such as 6-tile or EPK, Redart or ball clay or even your own local clays. The choice of the clay you use will determine the color and texture of the wall. This earthen clay plaster has a little iron oxide for a gentle pink color. This coat can be considered a clay paint or Aliz.
The Final mix
Mix to the consistency of paint (you will apply this with a brush)
It is a good idea to use wheat paste (flour boiled in water) to act as a glue, you could use Elmer s glue, egg whites, CMC gum, or Additive A. Imbed found objects, finely ground straw or large mica for more visual interest. Most walls require two coats, the last being finer and smoother.
For this color chart the base Earthen Clay Plaster was: By Weight Click Here for Prices
50% Kaolin 6 Tile , 25% 90 Mesh Pure Silica Sand and 25% 60 mesh Mica
 Bioshield Paint
Prepare 1 cup (2.4 dl) of very hot water. Make a thin mixture of 3 tablespoons (45 ml) of white flour and cold water (just enough to wet all the flour and make it liquid enough to pour). Pour the cold mixture slowly into the hot water while stirring constantly. Bring to a boil. When it thickens, allow to cool. Smear on like any other glue.
|Self Supporting Cones||Large Cones|
|Heating Rate (degrees F/hr)|
Cone Prices Click here
We stock the cones with turquoise background as shown below.
|Self Supporting Cones||Large Cones|
|Bars Small Cones||Regular|
|Heating Rate C/hr)|
When starting a tile project, I always wipe each tile off with a clean soft cloth. This removes all the dust and particles that accumulate while packed in the case. If there are stains that you aren't sure what are, you can always fire the tile before working on it. This should remove the stain. tile by Donna
Pick a pattern that isn't too complicated. It isn't easy to get glaze into tiny areas. I transfer the pattern with carbon paper or you can also freehand a pattern with a pencil. I usually lay a piece of paper over the area of tile I'm not working on so I don't smear the pattern with my hand.
There are a few ways to outline your pattern. You can use wax or wax resist. Both of these methods will let the color of the tile show through when fired. If you want it outlined in black, use the Waxline pen or you mix Duncan's EZ012 Cobalt Jet Black and wax resist. This is mixed to a brushing consistency and used to outline the pattern. I always apply this with a brush. This mixture repels the glaze and holds it in place when firing.
The glaze is applied with squeeze bottles. This requires only one even coat instead of three when brushing glaze on. If the glaze seems to be a little thick to apply out of a bottle, add a few drops of water to thin. It may be necessary to use a pin tool, nail, or whatever to push the glaze into small areas that cannot be reached by the bottle tip. You can use any Duncan or Mayco glaze that is for cone 06 and is opaque. Translucent glazes don't work well. We especially like Duncan's Concepts as they come in smaller jars and there are hundreds of colors.
Two or more glazes can be blended in one area by applying the colors and before they dry, pushing them together. This works well when doing flowers or anything that wouldn't be just one solid color. It kind of gives a marbleizing effect. When the glazes are dried, fire the tiles to cone 06. After firing, the tile can either be framed, put on the wall with grout, or however you choose to decorate with them.
Now that you have mastered making tiles, let's do a mural for the wall. Be sure to have a pattern that will fit theTile by Painted tiles by Pumpkin. Alvira (passed on) area that you have in mind. It will be helpful to lay out the finished tiles so you don't put the design up in the wrong place.
The first thing you need to do is find the center of the wall. Mark it with a chalk line from top to bottom and from side to side. This will give you a plus sign in the middle of the wall. When you put the tiles on the wall, it is best to work from center out to avoid not having your pattern off center.
You will need to mix up thin set cement. Just mix up enough for the immediate area that you are working on. If it starts to dry out, it becomes hard to work with. It is best to use a tool that has ridges to apply the thin set to the back of the tiles. This is called buttering the tiles. Make sure to get good coverage on the back of the tile before applying to the wall. Be sure to line up the tile with the chalk line. Most tiles have tabs on the sides for correct spacing. If need be , you can buy tile spacers or even use pennies.
Nails can be nailed at an angle under the tiles to hold them in place. If working in a large area, you can nail a one by two board across the entire length of the wall and rest the tiles on the board. Let the thin set cure for twenty four hours before removing the nails and or board.
You are now ready to apply the grout. The easiest way to do this is with your fingers. Mix the grout to a dough like consistency. Always wear latex gloves so the pigment in the grout doesn't absorb into your skin. Take a good size glob of grout and press in between the tiles being sure to get a good coverage. It is always a good idea to work an area then go back and clean the grout off the tiles with a damp sponge before it completely dries. After putting grout on the whole project, let the grout set up for at least twenty four hours. At this time, you can seal the grout.
Now you have a wall that will be the envy of your friends and family. Be prepared to have requests to do one at their homes.
Have fun and enjoy!
Although Paragon kilns and Skutt kilns may not approve, these Kilns are really accurate ovens, and they are self cleaning.
Turkey for Thanksgiving is really easy Kiln Cooking.
Place the kiln shelf near the thermocouple where the turkey will be easy to reach.
( see photo below of Paragon kilns)
Set the ramp to one segment, rate to 400 degrees per hour, temp to 325F and the hold to 3 1/2 hours depending on the size of the turkey!Paragon Kilns TNF-24 with optional Turkey. Kiln cooking at it's best! (An instant read thermometer should read 165-180 f in the thigh)
New York Steak Kiln Cooking Roast for Christmas 1999! Skutt kilns make Hmmmm roast beef. Good kiln cooking!
Kiln Cooking a roast in Skutt kilns is exactly the same as cooking it in oven at home. Purchase a whole New York state roast in a cryovac bag. Preheat Cooking kiln to 350 degrees. Rinse the roast and then dry, in the photo I have been cut in half so it would fit in the pan and cook faster. Season the roast with salt and pepper and perhaps a little garlic, roast in kiln at 350 degrees until it registers 125 degrees on instant read meat thermometer. Let rest for fifteen to 20 minutes. Degrease the pan juices, and serve on the side. because the heat in the cooking kiln comes from all around the roast the juices in the cooking pot do not boil, so they don't splatter.
It is not necessary to start the food at a higher temp to brown it. The side elements in the kiln act as an rotisserie and brown the food evenly.
Disclaimer: Both Skutt Kilns and Paragon Kilns would tell you not to try this. Especially if you fire a lot of lead based glazes. However I am sure my kiln is cleaner than your oven, really go look!
Send us a kiln cooking recipe to be included in this page!
This is a fun method of cooking and is sometimes referred to as "Beggars Chicken".
After washing the chicken, salt and pepper inside and sprinkle thyme into the cavity. Place lemon skins in cavity.
Mix lemon juice and honey together. Free the skin from the meat by putting a finger between skin and meat and then put lemon juice-honey mixture underneath skin. (You can also put lemon juice- honey in a baster with a needle tip and insert the mixture under the skin.) Put any remainder of juice-honey mixture in the cavity.
Baste the skin with olive oil and then salt and pepper to taste.
Take heavy duty duty aluminum foil or parchment paper and cover and seal the chicken in the foil or parchment package.
Roll out 3/8 inch slab of clay dry enough so that it still is pliable and cover the entire foil package with clay and seal. You can sculpt the clay in the form of the chicken underneath. Place the form on a cookie sheet and put in the kiln at 150 degrees for 1 hour to dry the clay somewhat and then raise the temperature to 350 degrees for another hour and a half. Remove the hardened clay form and then crack the clay covering with a hammer and remove. Open up the foil to reveal the cooked chicken. Serve with the juices accumulated at the bottom of the foil package.
Note: Use a groggy clay like a sculpting body or terra cotta. I haven't tried this yet but I plan to! BRANT
For your convenience we’ve provided these online SDS sheets and links in a PDF format for easy download. Locate the product about which you need SDS material; if the product lists more than one SDS, be sure to download them all.
“Safety Data Sheets” - SDS - have now replaced MSDS as of June 1, 2015.
SDS are detailed information bulletins prepared by companies that describes the physical and chemical properties, physical and health hazards, routes of exposure, precautions for safe handling and use, emergency and first-aid procedures, and control measures.
The information in an SDS must be presented in a uniform format using 16 headings in specific order. The new SDS format is derived from GHS guidelines, which have been adopted by OSHA and are now included in the amended Hazard Communications Plan (OSHA 29 CFR 1910.1200 - Hazard Communication)
Laguna clays SDS Sheets
Precious Metal Clay is now available In different versions called PMC3. Each is sold in the form of a lump, and PMC3 is also sold as syringe, paste. Art Clay also is available in three versions, Art Clay, Art Clay Slow Dry, and ArtClay650. Here are a few frequently asked questions about the full range of PMC products.
* Why six products? Do I need all 6?
PMC+ , Art Clay and Art Clay Slow Dry fire very quickly and result in a dense and durable material. they also allow for firing at three different temperatures. the lowest of which allows including glass and some gems that cant be fired hotter.
How do they do It? In the end is it all silver?
the above Information is from the PMC Guild and Art clay world.
Gerstley Borate Update
Gerstley Borate is in stock and not going anywhere!
July 4th 2014 Click here to see prices.
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.
In early 2000 U.S. Borax shocked the ceramic community by announcing that, for safety and economic reasons, they were ceasing operations at their California Gerstley mine; the source for a unique sodium borate mineral utilized as a basic ingredient in many ceramic glazes for decades. Upon learning this news, Laguna along with other ceramic suppliers and individual ceramists began, in earnest, to research a suitable substitute for gerstley borate.
This past April, Laguna Clay Co. learned that there remained a limited amount of mined but unprocessed gerstley borate at the now defunct Gerstley mine. Laguna entered into an agreement to purchase all the remaining Gerstley and is milling it to the same specifications as the Gerstley sold over the past 30 years.
While this supply is limited, based on historic usage Laguna anticipates having an adequate supply for many years. 3000 tons or 6,000,000 pounds as of 6/18/2011! Lots of people were offering synthetic Gerstleys but nobody switched to Laguna borate or suitable substitutes, as they were not as cheap as real Gerstley.
Trace minerals 0.079%
Gerstley from Laguna clay
An older post.... no longer true
As you know Gerstley Borate is no longer available, we have 3 substitutes we have tested and with feedback from our customers we are getting to have a feel for the problem.
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.
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.
Dal Tile's GB substitute from Mexico, we are still waiting for a sample.
Even Older notes on GB......
Laguna Borate looks like the answer to vanishing Gerstley Borate
April 14, 2000
After 3+ months and scores of glaze tests, we've come up with a blended material that looks like the best possible sub for Gerstley Borate.
You may have heard about Cadycal and other raw materials being tested to take the place of Gerstley, but we found that where those materials work some of the time, Laguna Borate works in virtually every glaze we tested Raku, low and high fire. And guess what, the blended Laguna Borate is actually cheaper than Cadycal! CADYCAL has been discontinued.
The next step is for you to test Laguna Borate in your glazes and your firing conditions. To make this as painless as possible, we re offering the following special as advertised in the May issue of Ceramics Monthly. If you have any questions, drop me a line at firstname.lastname@example.org.
February 18, 2000
The last two weeks have seen some extraordinary activity in terms of Gerstley sales. 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.
The "first-come-first-served" plan that Laguna announced five weeks ago is clearly not working. Our hope was that customers would buy enough Gerstley to sustain their production through the time needed to develop and test substitutes for the material. However, it appears that a small number of customers are trying to stockpile as much gerstley as possible for their own economic gain, while others are purchasing a lifetime supply, leaving the majority at risk of not getting material essential for near-term production.
Given both this "run on the Gerstley bank" and Laguna s declining supply, our singular goal at this point is to be as fair as possible to ALL Laguna customers. Our intention at this point is to provide Laguna customers a quantity of gerstley equal to a six months supply, or one-half the quantity you purchased from us in 1999. It is our hope that Laguna distributors will manage their supplies in a similar manner. Based on the state of our current research, a suitable Gerstley substitute should be available well before the depletion of a six months supply.
As time goes on, the body of knowledge concerning a Gerstley replacement grows. Laguna has developed a fairly complex formula that is quite close to a chemical match for Gerstley. It has proven a successful substitute in 94% of Laguna s glazes to date; we hope to reach the 98-100% level soon. In addition to Laguna s research, Tony Hansen, with help from Tom Buck, has posted an intelligent treatment of the Gerstley subject on his web site: http://digitalfire.com/gerstleyborate/, and Mary Simmons contributed a helpful post January 15 to the Clayart discussion group.
We are all unhappy that Gerstley is no longer being mined, but this is a challenge that faces the entire industry. We are confident that the challenge will be met, and soon; but in the meantime let s treat our colleagues with the utmost of respect and fair play.
We ll continue to keep you posted on this site regarding pertinent information on the Gerstley Borate situation.
unsigned by someone at Laguna