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Bory 1 Fara Shimbo Crystalline Glaze

Code: B1
Modification Date: 2013-03-25 08:47:26
Member of Group: Crystal

High Boron, Opaque Cone 6-10 glaze

Ferro Frit 311050.0 
Zinc Oxide27.0 
Titanium Dioxide4.0o
Gerstley Borate3.0 
* c-colorant, v-variegator, o-opacifier, s-suspender

Firing Schedule

Rate (C)Temp (C)Hold (Min)Step


Purpose: To obtain greater firing range and more "flowery" crystals by the addition of extra boron and calcium.

Tony Hansen gave me the idea to try a higher boron glaze in order to get the peak temperature down to something that wouldn't be so hard on one's elements. I thought D8-9 would be a good target since it doesn't supremely stress the elements but still allows most porcelain bodies to mature. The boron level in this glaze is actually quite low compared to many other (non-crystalline) glazes, but the effect of even this little bit of boron and calcium is exactly what I had in mind.

Bory 1 is a base I made up simply as a test, and it has now surpassed the old Octal (see the first edition or the Crystalline Ceramics Web Resource) on my list of favorites. It's so straightforward and dependable that it's my base of choice for workshops. Since coming up with this recipe, Bory 1, I've tried eight slight revisions. But in this case, the original is still the best. I did make a lower titanium version which was quite nice too, by lowering the titanium dioxide to 3% and upping the zinc, frit, silica and borate by 1/2% each. It works very well and gives lovely copper turquoises.)

I've tried this glaze with both the new synthetic borates and with Gerstley Borate, and found the old standard the best for my purposes, since it gives me the brightest and purest colors.

Bory 1 produces crystals in profusion, but only rarely does it cover a surface completely with crystals. So if you prefer to see a lot of ground, this is a good glaze for you. As often happens, it will felt up with additions of cobalt, and occasionally with copper, so I suggest not going over 2.5% cobalt carbonate or 2% cobalt oxide and adding 0.5% vanadium or rare earth oxide (of your choice) to prevent felting.

Bory 1 and nickel - either carbonate or oxide - are not a match, due to Bory's high titania content. But you will get some good results with the transparent-ground version mentioned above.

So far as I can tell, mixed Bory has a decently long shelf life (over six months though I've never used any beyond that; I always run out first). I've fired Bory 1 as low as D6 and gotten some nice crystals; however, at D5, you'll need to seed the crystals, as they won't form on their own.

To use Bory at D6, fire to 1221C, hold there for 20 minutes, cool slowly to about 1070C, and then hold anywhere between 1010° and 1140°. You will find much less variation in crystal shapes at D6 than you will at D9 (actually, this is true of just about all these glazes).

One point I should mention is that Bory is quite soft. It is very easily scratched so probably not a good glaze for any object that is going to be well handled.

The firing schedule provided with yield broad, flat crystals which show two rings of different shades. The inner ring, formed at a higher temperature, will be darker than the body of the crystal; the other ring, formed at a cooler temperature, will be a lighter shade. The effect is best seen with cobalt and iron colorants. Nickel should not be used with this amount of titanium or a sickly green will result.


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By Tony Hansen


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