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#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.





#68533 Small Jugs Pour Badly

Posted by JBaymore on 24 October 2014 - 03:06 PM

Do some studying about pitcher lips, and make new ones.





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#68317 Well Said

Posted by JBaymore on 21 October 2014 - 06:43 PM

Also the drama ... "Every single piece I make is ripped from my soul."


What Chris.... your's isn't?   Clearly your work process is lacking ;)





#68193 Small Stuff Sells-This One Sweet Dish Is From Oldlady

Posted by JBaymore on 19 October 2014 - 09:36 PM

i died on an operating table in 1974 but i am still here.  i celebrate the name.


And may you celebrate it for a long time to come!





#68113 Are We Being Hacked Again?

Posted by JBaymore on 18 October 2014 - 05:55 PM

FYI.... my guess is that most of the SPAM that happens here the average forum member is not even seeing....... the Mod team is getting them before too many folks see the garbage they post. There are a few forum members that are "eagle eyes" in spotting these posts (thanks!) and are hitting the "report" button at the bottom of the offending posting... and then the Mods go and kill the little suckers accounts ;) .


A LOT of this junk happens in the wee hours of the night. I got a lot of them before anyone reported then when I was in China.... 12 hours "off" Eastern US time.


best ,



#67001 My First Show!

Posted by JBaymore on 01 October 2014 - 07:55 AM

Steven is a wise guy. (read that with a pause between "wise" and "guy".......... not as "wiseguy". ;)





#66897 How Do You Take Photographs And Keep Them Consistent?

Posted by JBaymore on 29 September 2014 - 10:51 PM

Try to find a course on digital imaging. You'll learn amazing things. Like how certain file types deteriorate every time you open them.


If you camera supports RAW files...... use them not jpgs and the like.


Learn to use Photoshop.


Remember to white balance the camera before each shooting session.


Let your lights "warm up" before shootiong.... the color temperature changes a bit. Let em' stabilize.


Learn to use the in-camera metering system...... average weighting versus spot and so on.


Learn to use reflector sheets to fix lighting.... (can be a simple as a sheet of white paper).


As Mea said... bracket exposures like you used to do for that strange stuff........ film. ;)


Use difusers on all light sources. Bounce the light when possible.


Standardize your backdrop material.





#66772 Cataloguing Glazes

Posted by JBaymore on 27 September 2014 - 04:30 PM

That is what computers do very well.


Skip paper... go digital.