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#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.





#70969 Can A Glaze With A Higher Coe Have Less Crazing Than A Lower Coe?

Posted by JBaymore on 30 November 2014 - 12:15 PM

Where are you getting the "numbers" for your glaze calc program?


The data you generate is only as good as the data you are using to work with.  (Remember the old computrer adage, "Garbage in, garbage out".)


If you are using "stock" data on the raw materials that came with the program... or something like the "teaching database .... which is often simplified so that students can learn how/why the calculation work........ then your accuracy of the calculation you are using is potentially off. 


Get the typical analysis sheets from your supplier for the SPECIFIC raw materials that you are using and load that material data into the materials data table in your program.


Also note that those pieces of printed information are just that .........."typical analysis" sheets.  The data that they supply is only as good as the complaince between them and what is actually IN the bag you got the material out of.


COE calcs assume a full melt and all of the oxides participating in the melt.  If some precipitate out.... they atre not part of the melt anymore.  So the COE part of the program cannot account for them anymore.  So glazes that have crystalline strucure as a part of their composition........ screw up the calcuations for not only COE... but also the general molecular formula.  Matt glazes are fully in this category.


No one has been able to model the performance of a conglomerate of crystalline and glassy phase material yet.  THAT is why you can't model the COE of a clay body.





#70539 Manchester, Nh | April 2015 | Anagama Woodfiring Workshop With John Baymore

Posted by JBaymore on 23 November 2014 - 08:49 AM

You can just bring me over there and I'll build you a nice big anagama. All you need is about $100,000 US. ;)





#70395 How Much Do You Stay Within Glaze Limits?

Posted by JBaymore on 21 November 2014 - 11:30 AM

It all depends on that for which you are looking.


The most "interesting" glaze surfaces typically are those that come from some so-called 'imbalance' in the oxide distribution in the melt, most often causing some chemical unevenness in that melt, the lack of full melting of some raw material component, or the precipitation of some silicate type materials onto the surface in the cooling phase.  Or all of the above.  Or takes advantage of a raw material source for oxides that casues a 'defect' as the glaze is melting ... that we look at as "nice" (ie. American Shino crawling). 


Keep in mind the "limits" that everyone talks about are for what might be defined as "good glass".  And that "good glass" is defined by relatively modern industrial standards. The criteria has as much to do with stability, REALLY long term durability, and consistency as it does with any aesthetic qualities.  THOSE are criteria for mode rn industry.  (There is a reason that bathtub and toilet and sink glazes look like they do.)


If you are not concerned about the same things...... then the "limits" can apply less and less to what you are doing.


If you are making food service wares....... then concepts like the leaching of potentially toxic materials likely should be in your list of desired criteria. 


If you are making sculptures for outdoor installations, then stuff like durability in acid rain and pigeon poop likely should be in your list of desired criteria. 


If you are making floor tile, then hardness and resistacne to abrasion likely should be in your list of desired criteria.


Understanding how the various limit formulas might help you evaluate your list of personal criteria is where the art of USING glaze chermistry software comes in. 


Only you can decide what those criteria are. 


The only formal "laws" relative to the production of ceramics in the USA at the moment are from the FDA and the State of California... and they pertain to any wares that contain lead or cadmium compounds.  Not hing else is formually regulated.  You also DO have what are known as standards from organizations like ASTM for the labels of things like "microwave safe" and "dishwasher safe".  Of course general liability law says if something you make harms someone... you can be held liable in either civil or even potentially criminal (unlikely) situations.


Then there is a piece that is the "moral" dilema.  If you make wares that are somehow "sub-standard" in some way....... and you know that they are....... what do you do with them?  For example, if you have a dinnerware glaze that is drop dead gorgeous........ has NO toxic components...... but it is outside limits.... and the way it is outsisde those limits tells you that compared to a piece of commercial Noritake dinnerware....... the surface will not stand up to repeated washings as well......... what do you do?


NO easy answers.


Anyone who uses American Shino and sells it is "outside limits".  (Guilty!)  Anyone who woodfires and sells work with natural fly ash deposits is "outside limits".  (Guilty!)





#70014 Pottery Supply Store In Tokyo Or Kyoto

Posted by JBaymore on 16 November 2014 - 12:18 PM

Congratulations on the trip. Enjoy.


In Tokyo itself.... easy one for a tourist to find is "Tokyu Hands" ... one store in Shibuya and one in Shinjuku.






They have all manner of neat stuff... and they have a pottery section. You'll likely find what you are looking for there.


If you have the time....... get to Mashiko-machi. It is possible as a LONG day trip from Tokyo. Better to stay one night at the minimum. Shinkansen from Tokyo to Utsunomiya. Bus from there to Mashiko. Utsunomiya station has an information stand that can get you to the right bus (they typically speak a little English). Announcements for Mashiko are on the bus in English.


There is an all train route to Mashiko... but the changes can be a bit difficult unless you speak a bit of Japanese. (Perticularly due to a potential train split where some cars go to a different place..... and you have to be in the right section of the train. ..and they do NOT announce that in English.) 日本語が話せますか。


In Mashiko, near the "Potters Square" (on the oppoosite side of the street) is the Mashiko Kumiai ... the town's ceramics cooperative store. Lots of tools and raw materials there.





#69785 Dont Let This Happen To You!

Posted by JBaymore on 12 November 2014 - 11:38 AM

Years ago (like 15-20 now I think!) I did a survey (via the CLAYART listserve) relating to "kiln disasters" for a major presentation I was doing. 


There were a HUGE number of electric kiln "disasters" reported to me.  Way more than I expected.  Very few gas kiln ones.  There are more electric kilns in use than gas kilns... so this is skew is a bit what one would expect.... but it still was amazing how many fires and near fires got reported to me.


The main disasters that were reported from electric kilns involved a fire or a near fire at the junction box on the wall where the kiln connects to the stuidio/house wiring.  A huge proportion of THOSE related to kilns that were not hardwired into the electrical supply (ie. plug in kilns). 


The issue in both cases is mainly the eventual slow corrosion of the connections combined with the sustained high amperage draw of a kiln.  The plugs and socket corrode (surface oxidation).  Corrosion equals resistance to electrical flow.  resistacne to flow equals heat energy created from electricity (just like ion the elements).  Heat generated where you don't want it...... equals problems.


If put in correctly the hardwired ones get an anti-corrosion compopund on them.  And are TIGHT connections.  Plugs and sockets need checking regularly.  Be careful .... literally LETHAL voltages present when doing this work.  If you don't know how to do this safely....... hire a pro.   (do a Google search on "lock out / tag out" procedures too!)


CHECK those kilns folks. Routine maintenence is the word of the day.


Having a "pilot chacklist" to use as a standard reference before a firing is a good thing.  Works for aircraft pilots.  It makes sure you don't forget something (like the pair of pliers inside the kiln!)





#69649 Wood Fire Query

Posted by JBaymore on 10 November 2014 - 09:07 AM

Were those cut with a cutoff wire or string?





#69597 Does Your Kiln/wheel/other Have A Name?

Posted by JBaymore on 09 November 2014 - 10:09 AM

My noborigama is "Kawagama".  The anagama we just built at the college is "Fushigigama".


Sometimes I call my other stuff names........ but those can't be put on here.  ;)





#69507 To Submit Or Not To Submit

Posted by JBaymore on 07 November 2014 - 01:21 PM

Around here, the judge spends the night in the home of the best friend or spouse of the winners, who also hangs the shows, so I don't think the awards mean much.


Make sure not to paint the whole universe with the same broad brush.





#68854 New Technologies

Posted by JBaymore on 29 October 2014 - 08:38 AM

We've got a four channel data logger on our new anagama....... melding 21st Century technology with 5th Century technology. ;)





#68686 What % Of The Sale Price Do You Receive?

Posted by JBaymore on 26 October 2014 - 09:31 PM

When you wholesale, the shop then owns the merchandise free and clear of you.  They can price it or discount it as they see fit (unless you have some sort of legal contract stating that is not allowed.)


If they think they can get 400% markup...... and move the items... they will.  If that is happening, it says you are likely underpricing the work.


If you are consigning... look up your state's consignment laws.  And get a written CONTRACT.  No contract... no wares left.