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#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.





#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?