Jump to content


Member Since 06 Apr 2010
Offline Last Active Today, 12:29 PM

#96853 The Great Pottery Throw Down

Posted by JBaymore on 06 December 2015 - 11:31 AM

GiselleNo5 said :


I hate elimination challenges because what if somebody is just having a bad day! Or week! What if their cat died or they have a cold? I think that knowing they can be eliminated puts so much pressure on and not everybody performs well under pressure. Some people panic and their brain shuts off and they make stupid decisions or can't think clearly.


These "reality" type shows are about creating that kind of situation deliberately.  Watching people "self destruct" makes so-called "good TV".





#96812 Have You Timed Yourself Making A Mug?

Posted by JBaymore on 05 December 2015 - 11:29 AM

When someone asks about how long it takes, just include the years of practice and all the failures averaged into final product!


Famous HAMADA Shoji quote"  "60 years and 15 seconds".


Was printed on a fund-raising T-shirt for Mashiko after the Great Eastern Japan tsunami/earthquake.





#96581 Discolored Bisque

Posted by JBaymore on 30 November 2015 - 11:24 PM

This situation is a VERY common issue when dense stackings are made like that one described AND there is inadequate air circulation within the kiln.  I bet that the "white" mentioned is actually a bit of a grey-ish white tone.


This is the impact of reduction of iron oxide in the body at low temperatures on the bisqued clay. It comes in the densely stacked areas because there is not enough oxygen circulating to burn out all the carbonaceous matter in the timeframe of the firing profile, and that production of CO in the body in the localized areas reduces the iron.  Iron in the reduced valiancy (black) state is a powerful low temperature flux on silica.  So it starts to flux a bit of the silica in the bisque.  Produces a grey-ish bisque color out of many clays. 


High reduced iron fluxed glass is also "punk" and brittle.  Usually causes the sound of the "ring" to change too from normal.


This is a common cause of defects that show up in the glaze firing... and people do not realize that the issue happened in the bisque firing.





#96347 Centering Tools

Posted by JBaymore on 25 November 2015 - 10:39 AM

There is no substitute for skill development.





#96239 Do You Eat Off Your Own Pots Everyday ?

Posted by JBaymore on 23 November 2015 - 11:34 PM

We use my work at some level just about every day.  Some is 1sts... a lot is 2'nds (I don't sell them....smash most).  Some pieces I have made 'just for us' (not forms or glazes that I sell).  Plates, bowls, mugs, serving pieces, stuff like soy sauce bottles, and so on get used almost daily if not daily. 


We also use other people's pieces a lot mixed in with mine.  We have a lot of work from Japan that gets used regularly. Nothing typically "matches" in the western sense of a "set of dishes".


Joseph mentioned above the idea of potential concern about using 'expensive' pieces.  I think that if they are intended as functional work, they are intended to be used.  Respected, and used with care, but still used.  If they aren't used, half their 'reason for being' is not realized.  I use stuff like yunomi from artists from Japan that are in the $1000 range kinda' regularly.  They certainly aren't "piled in the sink" after use ;).  I use Yixing teapots (decent ones....$500-600 range) for brewing good tea like pu'er.  Decent Chawan and chaire and mizusashi for serving matcha.  And so on. 


Have I ever broken any?  Yup.  Not often... but it has happened.  (That is where kintsugi comes in.)


If we, as makers of functional objects, believe the idea that the things we make add value to life and increase the enjoyment of activities like eating and drinking, then we owe it to ourselves to take advantage of the opportunity we have to partake of that benefit.  And if we do not use our own work, and that of others, we are missing a valuable learning opportunity to assess the success of various pieces to accomplish the aforementioned goals.


I have pieces in a number of museum collections.  They are intended as functional objects. While it is a great honor of course to have that happen, there is a little "pang" of regret I always have knowing that the work will be locked away in a glass case, never to attain the goals of what it was intended to be.  Never to be truly realized in its fullness.





#96080 What Kind Of Sponge Do You Use When You Are Throwing?

Posted by JBaymore on 20 November 2015 - 11:04 AM

I rarely use a sponge at all.  I throw pretty dry. mainly use slurry when throwing.  (I also take the splash pans off the wheels I use....better access to the bottom of the form for me and better for demos when students are watching.)  Occasionally pick up a sponge to get "junk" cleaned up on the occasion that needs it. 


Because it is only "occasional" use....... I really have no significant preference... whatever is handy.


I want the contact between my hands and the clay to be unaffected by anything between me and the clay whenever possible.  Sensory feedback as the work is happening. 


Keeping the clay dry keeps it from softening.





#95966 Laguna 65 And Crazing

Posted by JBaymore on 18 November 2015 - 10:19 AM

There are a couple of different approaches to calculating theoretical COtE in glazes.  They give a bit different numbers. 


Where did you get the number for the body? (Which has to be from dilatometer... you can't calculate that number mathematically for non-glassy phase materials -yet-.)  That is a somewhat low expansion body (if that number is accurate).


What method are you using for the COtE in Insight for glazes?  And remember that the calculated (as opposed to measured) COtE for a glaze ASSUMES that the glaze is at a fully glassy phase state.  If anything precipitates out as micro-crystalline materials upon cooling....... the calculated COtE number will be off a bit.  This has a huge impact in a lot of "studio potter" type glazes.


Another factor to keep in mind with all of this stuff is where are you getting your materials data for the glaze calc program?  Are you using the "stock" MDT tables that are installed in it.... or are you updating with YOUR supplier's "typical analysis" sheets?  The slick looking software (of any kind) with all those pretty numbers is only as good as the DATA that it is working with.  (Old computer term... garbage in-garbage out.)  Even with the best info you can easily get (current typical analysis sheets), the data is only 'close approximations' (at best) of what is in those bags you are weighing your glaze batches from.


We can get all caught up in what looks like precise science....... but such software is only ONE tool in the ceramist's toolbox to deal with this stuff.  Gets you in the right ballpark.  Test, test, test.


The best method to deal with this issue is to use 'the glaze series that has a steadily increasing COtE' method that David mentions above.  (I have my students do this in the materials course every semester.)


And yes, call the supplier to check their thoughts.





#95941 Throwing And Trimming Off The Hump

Posted by JBaymore on 17 November 2015 - 01:12 PM

I think I've mentioned this before on here when this subject comes up.... but can't remember clearly (getting old).


There is a technique to the off the hump process I was taught in Japan that deals with this potential issue.  And even knowing this trick that helps to even out the shrinkage torque stresses in the base area of forms.... different clays trend to respond to this process in different ways.  Some clays just do not like to be formed in this manner.  Most folk processes of forming come from what the particular clay body in the area needed to be used to work well.  (In Jindezhen a couple of weeks ago, I just watched them joining porcelain parts bone dry.  It works with their clay.)


The whole use of the term "compression" by potters is a bit of a misnomer, and I think sets up a thought process that is not all that accurate a picture.  By channeling the malleable plastic material thru some sort of 'narrowed channel' (between fingers, or tools, or fingers or tools and wheelhead, etc.) you realty are simply aligning the clay particles surfaces with one another a bit.  There is nothing to really "compress out" of the clay.  It is not like there are major voids or airspaces to get rid of.  This alignment of particles helps with keeping the rate of shrinkage when the clay starts to dry out the same in all parts of the wall sections.


S cracking in off the hump stuff happens when the directions that the clay particles are aligned does not "match up" well in all parts of the form.  So different parts shrink at slightly different rates... and it sets up stresses that must be relieved.  The impacts of throwing torque in off the hump stuff is the main culprit in this issue.


So on to the stuff I was taught.........


The top part of the mound is coned up and then back down aggressively as the very last move before opening.


The ball of clay at the top of the hump is centered off from the rest of the mound as quickly as possible.  It is basically part of the coning downward move mentioned above.... it all happens sort of at once.  The longer you take to do this separating and centering part of the process with the ball at the top, the more torque effects are placed into the clay mass at the narrowed dividing point between the top (the piece you'll throw) and the bottom of the overall larger mound.  This sets up potential stress issues.


The clay is then opened and then is immediately formed out into a flat dish shape with a smooth slightly curving upward inside base.  (Looks like a small thick dish.)  Usually done with both thumbs on the inside at about 180 degrees to each other (9 o'clock and 3 o'clock).   This is done even if the end form is a Chawan, a bowl, a bottle, a teapot body, or whatever.  Then the base inside area is gone back over with the fingers from inside to outside at least once and back in to center to "compress" the area.  Sometimes a rib or tool is used to do this "compressing" also.  There is a definite slight "lowering" of the overall floor profile here at this point.


Then the initial dish shape is cupped upward quickly into a thick "ball" or "cylinder" type form to begin the real pulling actions.  Then the piece is formed.  Last step is a slight "compressing" of the interior floor...... either with fingers or something like a cow's tongue rib.


Speed is key in all of this....... long times of fussing and skin or tool contact with the top part of the clay compared to the mass at the bottom increase the torque effects that get concentrated at the "connection point" (where eventually you'll cut it off).  Another factor is not letting water (or lots of slurry) pool in the base of the inside of the form....increasing its water content... and hence shrinkage compared to the rest of the walls. 


Trimming is also important.  Thickness should be quite even compared to the walls.   In Japan the trimming direction is often opposite to the throwing direction.... helps even out torque stresses.  And sharp trimming tools also... so as to not add torque stresses......... cutting not scraping.


Seems to work for me.  I get very little S cracking in forms I make off the hump... and I do a lot of stuff that way.


But some clays just don't work for this process.  (Related....... I've used some clays in Japan that you simply CAN'T cover with plastic..... they crack 100% of the time.  You cover them with newspaper.  Or ones that can't be places in the sun to dry for even 1/2 hour.... crack 100% of the time.  And so on.)





#95537 "i Covered Expenses ....."

Posted by JBaymore on 09 November 2015 - 07:31 AM

The advice I offer year after year is to tell potters to walk through retail store China departments ... Look what they are getting for machine made goods!!! Price accordingly.


Been doing the same thing with students for years, Chris.  We tend to "apologize" for wanting to get paid for what we do by pricing way lower than what we should.  If we sort of 'line up' two pieces of well-designed, solidly functional, aesthetically pleasing, technically well-executed, work side-by-side.... one commercial 'manufactured' production and one studio artist handmade... the prices should, at the minimum, be just about the same.  (Because of economies of scale, and other industrial factors alone, the handcraft one should be higher.) 


But one side issue ALSO comes in here, and that is the internationalization of the world's economies and the differences in monetary exchange rates and the like.  In southeast Asia and China the 'value of a Dollar' is very different.  And southeast Asia and China are the current "drivers" of the production ceramics world, which is getting exported worldwide.  So a wholesale commercially machine-made mug in China selling for their equivalent of their $1.00 buying power is only about a $0.16 cost here.  Hence the 'Walmart level pricing' for certain types of commercial production wares.  And this tends to depress the valuation of ceramic production (from a very "price-per-object" standpoint) elsewhere.


It has more-or-less killed commercial ceramics production in the USA.  And interestingly, also in Japan (many, many shuttered production facilities now).


So the approach is not to compete on price....... you simply can't beat production machinery and Chinese and southeast Asia production costs.  Compete on the quality of the work.  In our case... on aesthetic quality mainly.





#95429 "i Covered Expenses ....."

Posted by JBaymore on 07 November 2015 - 10:08 AM

Everybody who stands to make a buck off an artist's dream will line right up and do it ... without batting an eye will take your money year after year. They are filling space ... Be it a booth or a Gallery shelf or a sales website.


Thanks for hitting this issue directly, Chris.


I've said this before on here....... the best way to make a decent living in the handcraft pottery business field (or any handcraft medium) is off of the flow of starry-eyed artists/craftspeople wanting to make it all work as a FT gig.  This is also tightly related to the "just do it for the great exposure" business.


There is (unfortunately) a seemingly endless stream of newcomers that "throw money at it" for a while until they eventually give up.  Many people "live off" that stream of 'broken dream Dollars'. 


To be in the running for the long haul as a FT artist/craftsperson of one sort or another, you typically need some mature, quality work, a decent understanding of basic business principles,  and the resources in the bank to sustain the business until it will make the money you need.  And unfortunately often a dose of "in the right place at the right time".


Too many people want to rush to the "full-time pro" category way before the work is at a level that will really make that concept work.  And in so doing often shoot themselves in the foot.  Nothing wrong with being a great avocational ceramic artist for a while...... or permanently. 


If you make great stuff...... well... you make great stuff.  Even if your main source of living income is something else other than clay.  No shame in that.





#95315 Interesting Dervelopment In Glass.........

Posted by JBaymore on 05 November 2015 - 09:50 AM

Ceramic related....... (alumino-silicate stuff is "ceramic").... but not yet into our exact world. 


Wonder where this will go?







#95173 Help Me Identify These Bricks

Posted by JBaymore on 02 November 2015 - 11:54 PM

FYI.............. the hard brick PCE number rating is a bit confusing if you don't know the way it works.


It stands for "Pyrometric Cone Equivalent".   What that actually means is that if the brick material was made into the standard cone form, the cone would melt and the tip would reach the base at the PCE number.  It is not the cone that the brick is rated to withstand or the use temperature or anything like that.  It is when the brick materials will MELT.





#95007 Qotw: Are You Living Your Dream, Or Dreaming Your Life?

Posted by JBaymore on 30 October 2015 - 06:10 PM

It has been a great ride so far.  Hopefully I have a while left to keep going.





#93258 Adventures Of A New Wheel Teacher

Posted by JBaymore on 26 September 2015 - 09:50 AM

My love affair with clay got off to a rocky start due a teacher who made a big deal about me being left handed.  



In my opinion, the more important hand in throwing in the Western rotation direction (counterclockwise) is the inside hand.  Make the inside well......... the outside will follow.  Left handers have great control of the inside hand.  Righties need to learn to use the other one ;) .  (FYI... a rightie that, after 45+ years of claywork, is now a bit ambi.)





#93165 The Great Pottery Throw Down

Posted by JBaymore on 24 September 2015 - 09:53 AM

I bet potters are not as goofy as the the other reality show contestants.


I hope that they don't do the same garbage that the US type so-called "reality shows" do.  They select people to participate that DO have issues and are goofy and unstable and such on purpose.  They deliberately set up conflicts that they can see coming as they select the mix of people / personalities, and then put together scenarios that they KNOW will somehow "backfire" given the mix of people they put together......... and therefore make what they think will be "good TV".