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glazenerd

Calcium Borate

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Thanks Tyler:

 

It has been discontinued according to Laguna. I had already looked up the chemical analysis: CA 18.88%. and B2O3 27.47%; which is fairly typical of standard gerstley borate: although they did add some calcium carb. It also has a fair amount of MgO and Na: which I am trying to avoid. Most gerstley or substitutes come from Ulexite, although the old Death Valley mine had limited veins of Colemanite/ Ulexite.  Actually I was referring to a form of Colemanite from Turkey that is much purer: B203 40%, and CA 50%... the rest mainly Al203.

 

One of these days I need to get around to trying some Raku firings.  some interesting results from what I have seen. I have a 35 gallon heavy wall steel drum I have been saving for that day.

 

Glaze Nerd

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Are you sure about the figures for Turkish Colemanite? Pure Colemanite (2CaO.3B2O3.5H2O) is 50.8% B2O3, 27.3% CaO, but perhaps you're referring to another type of calcium borate.

 

I've heard Turkish Colemanite is quite variable (don't take my word for it though), so you might be better off using a frit like Ferro 3211, or Podmore and sons 2244. I have no idea how easy these are to get hold of, or even if they're still being produced. Apparently you can also get synthetic Colemanite, but I imagine it'll be quite pricey.

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Here is the material data sheet- and yes it does vary-

 

Safety Data Sheet - Ground Colemanite

1.1. Product identifier

Ground Colemanite (includes Calcined, Uncalcined, and Turkish)

Colemanite - Di-calcium Hexaborate Pentahydrate    78.00-80.00

Calcite - Calcium Carbonate   8.00-12.00

Dolomite - Calcium Magnesium Carbonate     2.00-3.00

Clay     6.00-8.00

 

As it turns out 40% B2O3 is the minimum tested amount, but can be higher.  The 50% CA is a baseline as well- but seems accurate.

 

Glaze Nerd

Certainly hope and pray that all our fellow potters and glazers down south, and points west are healthy, and their property is whole.

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Peter

 

Was going by the specs given me by the national sales rep. The MDS sheet does not give percentages of elements, other than weight. Did not realize it was blended until I reviewed the spec sheet that came with the sample. Guess I need to run weights on a calculator to get exact percentages of elements: what I get for listening to salesmen. This product is heavily used in the ceramic tile business, but have not seen it in any clay/glaze stores. I have a series of floor tiles that I wanted to use it with to strengthen the glaze.

 

Glaze Nerd

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Well, its 1:30 AM Christmas morning and everyone has been asleep for awhile except me. Guess my Christmas present is obsessing over the huge variances in specifications for Colemanite/Calcium Borate. Not so sure there is that big of differences in product as there are in people filling out MSD sheets.

 

Calcium Borate:  DigitalFire:   B2O3 55.37%   CaO  44.63  (pure elemental)

 

Calcium Borate: American Borate Co:   B2O3  40.0%   CaO  26.54% 

 

Calcium Metaborate:  B2O3  42.5%    CaO 34.7%

 

I have 1KG/2.2lbs of Calcium Metaborate; which I am very happy with the results. Have not tried the 2lb sample that the prior specs were given- salesman emailed claim. For the moment I am going to use the Metaborate analysis because I am already testing it and it is a lab reagent grade. Will email the salesman about the other: but guessing 40% B2O3, with 30-32% CaO is more accurate. Perhaps he typo'ed the 50%, instead of 30%? Merry Christmas!!!

 

Glaze Nerd

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MSDS sheets are not that useful for getting specs on materials other than for H+S issues.  Contact the suppliers for what is typically known as a "typical analysis" sheet.  For some (most) proprietary materials they likely will not give you the analysis.... so the MDSD is the closest you can get.  But for basic raw materials..... they are far more useful.

 

best,

 

..................john

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Ty John

 

Spent part of the day recalculating COE. A few touch ups to bring it in line with porcelain; was not that far off anyway. Peter was fairly accurate with his percentage by weight analysis. In further reading: the B2O3 percentage can run between 37 and 42, and the CaO is what really swings widely 27-47 %. So I will use 40 B2O3 and 35 CaO as a baseline: after that I will just have to do run test for each 50lb bag. Can always throw in some Whiting if the CaO comes in low. It is accomplishing what I want it to do; so I will just have to work around consistency issues.

 

Glaze Nerd

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Tom,

 

I’m saying this to try to help you along your journey of learning about ceramics.  I don’t want to discourage you from posting here and I don’t want to make you feel bad, but there’s something that needs to be said.  

 

Before we go any further, I’m not sure if you’re aware of this, but it’s clear that what you’re saying and what you’re doing aren’t the same things.  I don’t know if you’re confused, or what, but you’re not formulating glazes from first principles.  It’s not possible to do so.  Your early posts implied that, and that’s definitely not what you’re doing.   Where are you actually getting your glaze formulations from?  Are they commercial glazes?  Are you using someone’s recipe from a book, even if it’s a modified form?  Let’s leave the dishonesty out of things.  we can help you better if we know what you’re actually doing.

 

And things are going to get really quiet around here for you if you don’t start listening to what people around here have to say.  You’ve shrugged off the advice of at least a century of collective ceramics and chemistry experience in your time here.  I don’t want to embarrass anyone, but a lot of the posters here have been at this since before I was in diapers

 

I genuinely have no idea why you’re bothering with lab grade calcium borate (which is like $60 per kilo/2.2 lbs) when you could get a 50 lb bag of Gerstley for about the same cost, or about 30 lbs of frit.    If you tell us what your end goal is for the product, we can probably help to get you there.  Are you trying to match a certain kind of frit’s chemistry?  Maybe ferro frit 3110, which is featured in every crystalline glaze recipe I’ve ever seen?

 

You sound like you’re trying to reinvent the wheel, and that’s going to get you nowhere.  Rather than wasting your money on ingredients no one uses, learn how the ceramics community has made glazes for centuries.

 

Get yourself digitalfire’s INSIGHT program.  Learn about unity formulae and limits.  Learn about how other people make their glazes.  Learn about classical glaze families:  celadons, shinos, iron glazes, raku glazes, simple clear glazes, copper reds, chun glazes.  Learn about the variable effects of ingredients like rutile and iron.  Learn about lead glazes (seriously), tin glazes, overglazes, underglazes, china paints and lustres.

 

Start listening.  We know what we’re talking about, but we’re not going to waste words on ears that can’t listen.

 

Mods, if this is out of line, I apologize and feel free to delete.  I know I make a habit of being "that guy," but I am trying to be better at it.

 

-Tyler

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Okay, now that we're on the same page, we can actually start to discuss your project.  First things first, you don't have unique needs.  You have the standard needs of any ceramist working with functional ware.  You're not the first person to make tile, and their realities are your realities.

 

You're going to need to familiarize yourself with limit formulae. (digitalfire article on the subject, I feel like you'll enjoy Tony Hansen's writing:  http://digitalfire.com/4sight/education/limit_formulas_and_target_formulas_206.html).  If you get a glaze within those limits, you'll have a glaze optimized for durability and functionality.  It should meet the TCA criteria, or at least start you on your way.  This is how functional glazes are formulated.  From teapots to toilets, they're going to fall within strict limits.

 

The second part is the bad news.  If you look at the formulas he provides, there ain't no way you're getting a functional tile out of a glaze with as much zinc oxide in it as a macrocrystalline glaze.  Crystalline matte glazes will fail too, likely.  It's too much flux.  Your hardness and leach resistance is a product of the silica and alumina and the flux is detracting from that.  Your alumina deficit is detracting from that.  Boron should be avoided as well--borosilicates aren't generally "hard" glass.  That digitalfire article will tell you more about that.

 

I'm not sure if the TTT diagrams will help you get a durable macrocrystalline glaze or not, but it will help you figure out downfiring schedules.

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Cone 6 is mainly floor only.. perhaps wall-- buyer demands what. Crystalline is for wall only- way too slick for floor use- liability issue. Will read those articles, more than happy to learn something new. However, known commercial floor tile glazes border on a borosilicate blend. Reason I looked into calcium borate to begin with: heavily used in the floor tile biz. Just as talc body clays are- up to 70%. Then again I do not have 100 ton presses to mold a dry mix with 4% moisture in order to skip the bisque fire. So my model is one clay that will do both floor and wall tile, and do both cone 6 and crystalline: which leaves me with a porcelain clay only. Already have that formulated- had to kill the plasticity. Started out doing cone 10, but that adds an additional 30% in product costs including kiln turn around time. I better be the first person making crystalline glaze wall tile on a mass production scale or my whole business model goes in the toilet. Curious to know how many crystalline glaze firings you have done?

 

Nerd

 

Facts & Figures from the online glaze calculator:

 

Cone 6 with Gerst/Bor     COE 6.95   CaO 0.172  B2O3  0.097  SiO2  0.876   Al2O3  0.131    Acid/Base 0.96

Cone 6 with Cal. Bor.       COE 6.39  CaO 0.195  B2O3   0.177  SiO2  0.817   Al2O3  0.127    Acid/Base 1.08

 

*Colemanite was used- no listing for calcium borate.

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Up your silica. It's too low. 325 mesh flint is my go to silica.  Edit:  Wait, where's your soda and potassia fluxes?  You're not just using boron and lime, there are other numbers that matter here.

Make 5 or 50 more of these within limits, price them out, and test fire.  Not all of them will work out. The best ones move onto the next round.  

Then, you're gonna test them against the ISO norms for ceramic tiles, which provides testing methods. You have this, right?

 

 

Regarding the number of crystalline firings I've done--countless.  I don't mess with zinc macro crystalline glazes, because it's not really my aesthetic, but I use crystalline matte techniques all the time.  Look at my website.  The urn with a spike on it is an example of a crystalline matte glaze made from wood ash over red and white shinos.

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If the figures in the first row come from a recipe using GB then there is data missing. Where are the MgO and Na2O figures? 

 

Also, if you get the “Typical Analysis†figures for whatever calcium borate you have acquired then you can enter that into the Insight MDT so you don’t need to use colemanite data in place of.

 

One more thing, are the figures you posted here for a floor tile glaze and not the crystalline wall tile? In the Glaze Test City thread you spoke of using Lithia and Zinc, is that info applicable to this thread? I’m confused as to what glaze these figures are relevant to.

 

I can understand that you might not want to divulge your recipe but it makes it impossible to offer our 2 cents with incomplete data.

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Think I figured out the problem: I am doing a very poor job of communicating. In this thread I am only dealing with the run of the mill, garden variety, Seger formulated cone 6 glaze. The only thing I am doing is swapping out CB for GB. I would take Peter's suggestion for the frit, but I have already began stocking Nep SY, silica, and a few other pertinent items. Have a cold, will deal with this more later.

 

Nerd

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I used Colemanite once, spat all over the shelves. Managed to fly off the pot with some force. Think I remember reading about the water being the problem and from a quick search Calcium Borate is Colemanite without the water.

 

The only frit I buy in the UK actually seems similar to the chemistry you are possibly after. I think. Is it the chemistry you are looking for or different properties? Lack of silica?

 

http://digitalfire.com/4sight/material/bps_calcium_borate_frit_134.html

BPS Calcium Borate FritCalcium Borate FritOxide	Analysis	FormulaCaO	26.60%	         0.980MgO	0.19%	         0.010K2O	0.45%	         0.010Al2O3	4.88%	         0.099B2O3	50.01%	         1.485SiO2	17.85%	         0.614

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I used Colemanite once, spat all over the shelves. Managed to fly off the pot with some force. Think I remember reading about the water being the problem and from a quick search Calcium Borate is Colemanite without the water.

 

The only frit I buy in the UK actually seems similar to the chemistry you are possibly after. I think. Is it the chemistry you are looking for or different properties? Lack of silica?

 

http://digitalfire.com/4sight/material/bps_calcium_borate_frit_134.html

BPS Calcium Borate FritCalcium Borate FritOxide	Analysis	FormulaCaO	26.60%	         0.980MgO	0.19%	         0.010K2O	0.45%	         0.010Al2O3	4.88%	         0.099B2O3	50.01%	         1.485SiO2	17.85%	         0.614

Close: 40% B2O3 and 27-28% silica. Boron is a glass former as well- sometimes we tend to forget that because SiO2 gets top billing. I have only fired the anhydrous colemanite twice: no splattering, no blistering- was very pleased with the finish. Obviously I am going to have to do some adjusting. However, that adjusting has to fall within the limits of my business model as well.

Tyler, I just bought a mixed pallet of dry materials in August, which included Imsil A-25 silica for .34¢ a lb. I buy very little from traditional pottery supply houses.

Min: when I get done reformulating, will post all the figures again. The NA, K, and Mgo were all at the lower end of the limits.

 

Nerd

 

Edit: The reason I want the CaO higher is so I can use it with any and all Mason stains. Can also remove the Whiting additions.

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I used Colemanite once, spat all over the shelves. Managed to fly off the pot with some force. Think I remember reading about the water being the problem and from a quick search Calcium Borate is Colemanite without the water.

 

The only frit I buy in the UK actually seems similar to the chemistry you are possibly after. I think. Is it the chemistry you are looking for or different properties? Lack of silica?

 

http://digitalfire.com/4sight/material/bps_calcium_borate_frit_134.html

BPS Calcium Borate FritCalcium Borate FritOxide	Analysis	FormulaCaO	26.60%	         0.980MgO	0.19%	         0.010K2O	0.45%	         0.010Al2O3	4.88%	         0.099B2O3	50.01%	         1.485SiO2	17.85%	         0.614

Close: 40% B2O3 and 27-28% silica. Boron is a glass former as well- sometimes we tend to forget that because SiO2 gets top billing. I have only fired the anhydrous colemanite twice: no splattering, no blistering- was very pleased with the finish. Obviously I am going to have to do some adjusting. However, that adjusting has to fall within the limits of my business model as well.

Tyler, I just bought a mixed pallet of dry materials in August, which included Imsil A-25 silica for .34¢ a lb. I buy very little from traditional pottery supply houses.

Min: when I get done reformulating, will post all the figures again. The NA, K, and Mgo were all at the lower end of the limits.

 

Nerd

 

Edit: The reason I want the CaO higher is so I can use it with any and all Mason stains. Can also remove the Whiting additions.

 

 

Holy cow, 2500 mesh silica?  Why? You know about the dangers of using such a fine mesh silica to the health of you and your workers right?

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I smell fish.  This guy's not being honest and is just playing games.  In Glaze test city he was converting 200 mesh silica to 600 mesh and "etching elements."

 

if you guys want to help him, thats fine, but i'm getting flashbacks of geremyh and Puck Goodfellow.

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I smell fish.  This guy's not being honest and is just playing games.  In Glaze test city he was converting 200 mesh silica to 600 mesh and "etching elements."

 

if you guys want to help him, thats fine, but i'm getting flashbacks of geremyh and Puck Goodfellow.

yes, indeed. i hope he has enjoyed his time as Master of Revels. 

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I do not buy Imsil A-25 silica from Axner, but you can check it out there.

 

http://www.axner.com/silica-imsila25.aspx

 

. A very finely divided or “micro†form of quartz physically bound together as loose agglomerates. Although considerably more expensive than silica typically used in ceramic glazes, microcrystalline is considered by some to be the “ultimate†silicate for use in glazes

 

Not sure who came up with 2500 mesh.... it is 325 mesh.  

Tyler, beginning to see why you have been labeled as "that guy." You make alot of assumptions, and swing to extremes.

min said: yes, indeed. i hope he has enjoyed his time as Master of Revels.

 

Joel, maybe it is best to message you privately.

Nerd

Edited by glazenerd
For a record

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Just so we're clear, and no one gets any bad ideas from the (mis)information here, 325 mesh silica has a median particle size of about 10 microns and about 98.5% of that will pass through a 325 mesh screen. 400 mesh silica is nearly the same, at 99% passing through a 325 mesh screen.  Imsil's A-25 silica has a median particle size of about 5 microns.  It's not 325 mesh sillica and in no literature anywhere is that demonstrated to be the case.  The way to interpret this data is that 50% of A-25 silica will indeed pass through a 2500 mesh screen, which is, quite frankly, too much of too small a size for safe use in the average studio.  Those tiny particles won't settle and will stay in the air for a very very long time.

 

I'll let everyone draw their own conclusions about the rest, but A-25 silica is most certainly not 325mesh and it's dangerous to claim that it is.

 

Citations:  

325m flint: http://www.pshcanada.com/Tech%20Data/Flint%2045.pdf

400m flint:  http://www.pshcanada.com/Tech%20Data/Flint%2040.pdf

 

Data on Unimin's A-25 silica:  http://www.thecarycompany.com/raw-materials/principals/unimin/imsil/

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