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Member Since 06 Apr 2010
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#72214 Inside Mug Color Change

Posted by JBaymore on Yesterday, 11:36 AM

OK... venturing into "dangerous grounds" here................  going off the "politically correct" spectrum........


This discussion above cuts to the core of one of the things I always mention in my ceramic chemistry classes.  Which I think is VERY important for students to really understand.  It gets to core ideas of "how the world works".


In general, how someone gets to be a "famous ceramic artist"........ is from the visually apparent aesthetic qualities of their work, the technical execution of the pieces (from a forming standpoint), and is often combined with the way they present themselves in public settings (exuding a professional feeling and being nice people).  Maybe add in a dose of "right place at the right time" serendipity, and also a bit of a "who you know" factor.


What this "fame" does NOT necessarily tell you is their depth of understanding of the technical sides of the process.  For all anyone knows... they flunked or got a D in their ceramic materials / ceramic chemistry / kiln design-building classes (if they ever had that kind of training).


They may have mastered the aspects of the process to get the visual result THEY use...... but that might be the real limit of their technical expertise.  They might even have had training that was not all that accurate, and are sharing that stuff once again, spreading the misinformation.


So just because "Famous Ceramist" shares some glaze recipe or some ideas on the technical side of things........ that does not make it automatically "truth".  There are things I've seen printed in studio ceramics oriented books that fly in the face of basic science and engineering principles.


Sometimes the information presented by "Famous Ceramist" is taken out of context, and then transferred to others incorrectly.  For example, a glaze used solely for sculptural work gets shared... and then a participant in a workshop comes back and shares it with their functional potter table-ware producing friends.  Suddenly it shows up on tableware.  Then that tableware potter (maybe who has little technical knowledge) becomes "famous"... and that glaze then goes on to be shared as a tableware glaze.  And so on.


Vet your sources folks, vet your sources.  Sometime the emperor has no technical clothes.






PS:  Luckily, most of what we do is not "death incarnate".  But having a good grasp of some basics is important.

#72165 Inside Mug Color Change

Posted by JBaymore on 20 December 2014 - 08:22 AM

OK without doing ANY formal glaze calculation in Insight...... let's look at  that colorant supply. 


That's a total of 10.3 percent of metallic oxides.  There are few to no glazes that can hold that kind of saturation of such coloring oxides in solution as the glaze melt cools.  Just ain't gonna' happen.  So some of the coloring oxides are going to precipitate out on the surface of the glaze.  Any oxides that are in this condition are almost certainly subject to easy leaching into strong-ish acids and bases.


Then looking at WHICH oxides these are.  Copper is notoriously hard to keep in solution in glazes.  And at 4% that oxide alone is flirting with the top amount that can even closely be stable.  Then there is 4% of cobalt OXIDE.  That alone is enough to make the glaze almost black and be supersaturated.  The manganese is there just for good measure to totally make this absurdly oversupplied with colorants. 


Then take into account that this looks like a Cone 6 recipe.  At Cone 6 a significant amount of boric oxide glass is introduced to lower the melting point.  Boric oxide glass is softer than silica glass... so this is a less durable base than if it were at Cone 9-10 or higher.  SO the glass has a lower ability to hold the oxides that are still IN solution also.  (note... yes adding B2O3 in very precise proportions to the SiO2 can harden borosilicate glasses... but just looking at the recipe, I don't thik that is the case here.)  If this is getting fired atr cone 9-10....... worse... don't need that boron.


NOT a glaze for food bearing wares.  Period.





#71883 Two Questions About Manganese Dioxide Use

Posted by JBaymore on 14 December 2014 - 07:59 PM

What get's ya' in ceramics are the unknown unknowns.  ;)





#71867 Quick Consignment Deal - Need Confirmation :)

Posted by JBaymore on 14 December 2014 - 03:35 PM

Signed contract specifying all the details including that the inventory remains YOUR property while in that store, not his.  Also specify what happens is shoplifting, shop breakage, or shop "wear" occurs.


Otherwise.... no go.





#71866 Two Questions About Manganese Dioxide Use

Posted by JBaymore on 14 December 2014 - 03:31 PM

I know too...... but letting others think about it.





#71753 Production Potter Productivity

Posted by JBaymore on 12 December 2014 - 01:13 PM

Another aspect of this situation is HOW the people responding are thinking about the response.


If a question was posed in a PRIVATE situation (unlike a public posting forum) ...... then a person responding would tailor the comments to the specific individual, and the specific questions.


But in a public setting...... often what is being considered by the person replying is the fact that MANY people of varying experience and background levels will be reading the postings,......... and that the posting will be "out there" basically forever (This is the Internet we are talking about here).   And thinking about the impressions and ideas that will be gained by others reading the thread.  Sometimes there are a broad spectrum of potential considerations that go into the answer for a specific person... that might not apply to others situations or concerns..


So sometimes... in such public venues.....  questions are answered that were not asked... for a VERY GOOD reason.





#71654 Adding Subtle Interest To Surface In Electric Kiln To Enhance Visual Qualities

Posted by JBaymore on 11 December 2014 - 08:57 AM

Program in a way longer cooling fire down curve.  The "interesting" stuff from most "reduction" gas firing comes not from the reduction.... but from the longer cooling cycle of the larger thermal mass and better insulated kilns.


It will surprise you.





#71578 Production Potter Productivity

Posted by JBaymore on 09 December 2014 - 10:38 PM

The reason I focus on the amount of clay here at times is that it is an indicator of low throwing skills for making that size form.  A certain sense of appropriate "mass" can be understandable...... but if these are considered functional pieces.... personally I'd find 2.75 pounds totally objectionable for a form like that.  I'd think that better balanced forms would likely increase sales too.


 Additionally those size forms should require NO leatherhard trimming to reduce anything of the wall thickness.  Trimming should be mainly for aesthetic reasons.... finishing the foot area of the piece  ... not to compensate for leaving unused clay in the lower walls......and this also reduces labor on the per piece basis... increasing the end point productivity.


Maybe a management visit to another production facility somewhere is in order?   Here's a very successful long term hand production pottery:  CRAP... cut and past does not work for me since I upgraded to IE 11 .... have to type this in.... look up on Google ....... Salmon Falls Stoneware.





#71385 To Sell Or Not To Sell? That Is The Question

Posted by JBaymore on 07 December 2014 - 01:31 PM



You'll need to file a State Registration of Trade Name" for a DBA situation... that ties up the business name in the State (but not nationally or internationally). Cheap........ $50 for five years.  Renewable.  That puts you on the State "radar" as a business... and is required if you are doing business for yourself.


You can do a sole proprietorship with simply doing that and filing a Federal Schedule C.  (Get business liability insurance if you do that.)


Until your business profits are above $50,000 per year.... no NH tax forms at all.  Business profits tax is for over $50K.


There's no NH sales tax ... so internet sales and sales in-state ... no tax collection nightmare..  No NH income tax either as you know.  (But also no NH social services or support structure to speak of... double edged sword ...... "Live Free or Die".


In some ways it is actually EASY here .


Here's a thought to ponder however........


As an ARTIST........ do you really want to focus on a BUSINESS NAME... or using you own real name?  One suggests more of a "commodity product"...... the other more of a one-of-a-kind art product.






#71377 Manganese Dioxide

Posted by JBaymore on 07 December 2014 - 10:46 AM

The granular manganese added to clay bodies is not JUST about the granular factor.  It is true that in 'bug lumps'... the issue of the available pathways for the material to get into the human body are pretty much nonexistent.


However, granular manganese is often packaged with what are called "fines".  Fines are the dust fraction.  That dust is typically not cleaned out from the large pieces when the clay body is mixed up.  So there is very likely a TRACE of very fine MnO2 material in any body containing granular manganese.  That is in the general dust that the body gets into the studio environment.  Likely this is a very low level.


The real potential issues are from the FIRING of manganese containing bodies. 


Manganese likes to "fume" from high fired wares.  Fumes are typically misunderstood by many potters.  They are not gases..... they are actually very tiny weenie, isty-bitsy dust particles.  So tiny that the molecular vibration of the air molecules will keep those particles suspended in even still air for 24 hours or more.  These escape into the kiln atmosphere.  If that kiln atmosphere escapes into the studio rooms, then some manganese fume is going with it.  THESE particles are highly respirable, and  therefore represent a high toxicity concern.


There is an interesting problem hiding here.  Most fuel fired kilns utilize significant draft flow,  and any stuff released into the kilns' atmosphere is typically mostly vented outside the studio spaces.  So manganese fume, if present, would mostly be picked up and vented elsewhere (if the kiln is installed and operated properly).  But electric kilns do not have this large volume draft flow.  And for what type of firing do we typically see granular manganese added to bodies?  Why... electric oxidation firing.... to add interest and variation to the clay body.


So the proper venting of electric kilns that are used to fire manganese containing bodies becomes of paramount importance to the POTTER.  If you don't KNOW that the vent system installed on your electric kiln is working WELL...... then you are "playing with fire" (pun intended ;)).


The second issue with the firing side of using granular manganese in clay bodies potentially applies to the CONSUMER.


Granular chunks of manganese concentrate a lot of the material in one place.  When you then put a glaze OVER this little spot, that MnO2 bleeds into the glaze lying right over it and colors it.  Nice.... great visual texture.  However that large saturation or OVER-saturation of manganese in the glaze at that point likely is at a level that will not hold all of the MnO2 in solution during the cooling phase.  So if you look at those lovely little speckles under a microscope, you'll notice that the surface is often micro-crystalline....with some Mn stained alumino-silicate forming on the surface.  This manganese is NOT bound well into the glaze melt... and can easily leach out.


How much this amounts to as a potential toxin for the user of the wares is impossible to predict.  It depends on so many variables and factors.  The particular clay body and how much manganese granules per square inch are on the surface, the nature of the overlying glaze, the thickness of application of that glaze, the firing cone, other colorants present, and so on.  The only way to accurately assess if this is an issue is a routine of sampling of the production and actual lab testing to KNOW the answer.


The comment above from bciskepottery about KNOWING your materials is probably the MOST important comment in this thread.  It is very easy to take 2 or 3 pottery classes, buy some equipment, and set up and start making and selling pottery.  It take YEARS of study and experience to actually know what you are doing.  Clay is long.... life is short.





#71290 The Morning Aftermath...

Posted by JBaymore on 05 December 2014 - 10:48 AM

We've been told (at the college) that Laguna is mixing clays softer deliberately.  Don't know if this is true or not.  We are considering changing suppliers if it is true.


Let's see......... selling water at $0.40 a pound.  At 8.34 pounds per gallon, that is a price of $3.34 per gallon.  You can buy pure drinkable bottled water at places for about $1.50 a gallon.  Our water supply from the town is fractional pennies per gallon.


Great deal..... add a pound of extra water per sale..... and make almost 40 cents extra.  Multiply that by the tonnage of clay sold per year... and that is a hefty hit to the bottom line... and without looking like you are raising prices to the consumer.





#71289 Slurry Mixed Clay Problem

Posted by JBaymore on 05 December 2014 - 10:40 AM

Clay bodies traditionally use potash feldspars for the sources of flux to develop some glassy phase.  The reason for this is that soda feldspars and feldspathoids are slightly soluble in water.  This can get soda ions into the water... and change the water chemistry so that the reactions with the charges on the surface of the clay platelet crystals change.  This results in some strange behavior of the plastic body.  The ph of the water used can affect this solubility greatly, as can any other ingredients that affect the water's ph.


This is why a lot of cone 6 white clay bodies are so squirrely; often neph sy is used to get the flux content up there to lower the range.  And they do NOT tend to age well (or reclaim well).





#71100 The Morning Aftermath...

Posted by JBaymore on 02 December 2014 - 01:50 PM

Ergonomics folks........ ergonomics.





#70981 Grinding

Posted by JBaymore on 30 November 2014 - 06:46 PM

@JBaymore: What do you mean exactly when you say "when you are in Japan"? Can you elaborate? 


I spend a lot of time working and showing (and hence selling) in Japan.  Therefore the comment.  The Japanese market tends to be more appreciative of inherent ceramic process and usually understands a lot about ceramics.


Does that help?





#70974 Top Ten Myths About Creativity

Posted by JBaymore on 30 November 2014 - 02:21 PM

.................practice makes perfect. 


Actually........ perfect practice makes perfect.  Practicing the same "mistakes" over and over and over just reinforces those problems. 


Reflective, critical, and directed practice, with consttant re-evaluation makes perfect.