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JBaymore

Member Since 06 Apr 2010
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#60916 Most Difficult Aspect Of Making A Pottery Business Work?

Posted by JBaymore on 16 June 2014 - 12:21 PM

I think that the question is intriguing....so thanks for posting it...... but probably is WAY oversimplified.  The answers to almost every question there will change based upon some very basic business premise variations. Let's take a look at a couple:

 

I can create a "pottery business" in lots of ways.  Let's look at 2 of them.   

 

Way #1..... figure out what people want/need, what they will pay for it, and then make those objects. 

 

Way #2...... make objects that you love to make, and then find people who are interested in those objects, and can afford to pay for them.

 

Those are two totally different approaches to running a "pottery business".  Both viable if you want to call 'economic success' the sole yardstick.

 

Or...........

 

Way #1 - I can create a "pottery business" that is solely comprised of myself.....a sole proprietorship where I do everything.  I use tools and equipment that is appropriate to that approach.

 

Way #2 - I can create a "pottery business" that is managed and guided by myself, but has a few employees that are taking on specialized aspects of the tasks involved, and I can invest in machinery that increases production efficiency commenusrate with a "small factory" kind of approach.

 

Again..... VERY different business models.  #1 possibly less capital and labor intensive... #2 likely very capital and labor intensive.

 

No one right answer for all.  However there might be one right answer for one specific individual.

 

I think for almost every industry/endeavor it is the distribution/sales channel that is the key to success.  The supplies and labor channel can sometimes be challenges to the business.... and sometimes fatal...... but they usually can be overcome if the sales side is there.

 

Small businesses almost always fail due to a combination of under-capitlization and poor planning for necessary start-up period cashflow issues.

 

best,

 

.......................john




#60810 10 Cool Trends In Contemporary Ceramics

Posted by JBaymore on 14 June 2014 - 01:35 PM

He wanted them to think. Not all aesthetic prose are pseudo intellectual.

 

Another 'amen' is due right there.  

 

The very CORE of our college department's ceramics curriculum is to get students to THINK.  We stress a heavily traditional route to develop that thinking...... but developing an understanding of their own work and how that "fits into the world" is very important.  It you want to go off and be "irreverant" and "non-traditional" then you better then be able to eloquently articulate the reasoning and route that lead you to that point. If you want to make "highly traditional work", you better be able to support that approach with the same level of analysis and impact.  You can work sculpturally, you can work functionally... but you can't work without actively THINKING.

 

BTW... I basically "ban" the oh-so-easy words "I like" from critiques.  I don't really care if a student likes or dislikes a particular work.  I want to know things like what the student actually sees in the piece being considered (ande hence what they may be missing), I want to know how the visual elements and principles of design are handled, I want to know what specicic feelings the work might produce (deeper than the usless "like" comment), if it is functional...... how has function been adressed and is it successful to those ends, I want to know what choices were made in the forming and decorating processes and why those particular choices were made, I want to know what historical references might have been researched to arrive at the work, and so on.

 

Anti-intellectualism is a trend itself here in the USA of late. Terribly sad.

 

I would strongly suggest that those that are having serious difficulty with this particular article..... go get a couple of books on ceramic art history and read up.

 

best,

 

........................john




#60396 Glaze Making/ Testing Again!

Posted by JBaymore on 09 June 2014 - 05:35 PM

I start my glaze calc students out with some "old" methods... and then lead them into molecular understanding and then into using glaze claculation software.  Works well.

 

First assignment..... research a glaze RECIPE (I immediately make the verbal distinction between a recipe and a formula... to set the stage.) in books or online (that fits the firing range used) that they LOVE, that is composed only of materials that we stock in the lab.  Bring in the recipe and images and share..... explain why they picked it and so on.  Then mix it up (that lets us get into how to DO that... stuff like accuracy of measurements and the impact of significant figures, use of lab tools, H+S procesures, and so on) and apply the glaze test to test cylinders (and record keeping and labeling). 

 

Then I have them research each of the raw materials in books and online.  Write me out (typed, etc.) a "book' on what they found out about the characteristcs of each raw material in their glaze recipe....chemical composition, what it comes from, where it is mined (if so), what oxides it supplies in the melt, what it does when mixerd in water, and so on.

 

Then I have them make a decision about changing one characteristic material from their list of ingredients.  Some pick different feldspars, some change from stuff like Whiting to Dolomite, some change the colorants, and so on.  It is their decision what to do.  (In the group setting... this lets me address a LOT of stuff to the group.)  Then I introduce the concept of scientific method (short version - change ONE thing at a time ....control all else), and a line blend and how that works.  They then set up a line blend system (11 points) and vary a SINGLE variable in that potential blend (sort of half of a blend....really just regular incremental stepped changes).  Next comes exchanging two items for each other.... a true line blend.

 

Eventually when we have fired results, and can look at an analyze them, we then look at what the material changes did to the oxides in the melt in each case.  Slowly we shift from a materials based approach to glazes to an oxide based approach.

 

15 weeks......... two - 3 hour classes a week, plus homework time.  By the end....... they can mix up glazes, organize tests, do recordkeeping, use Insight at a basic level.. .... and know what they are doing at a basic level.  (At NHIA we now just instituted Clay and Glaze Chemistry II in our curriculum starting in the fall BFA semester.... YES!)

 

Don't get overwelmed.  There is a lifetime of study ahead of you.  Take baby steps.  You'll get there.

 

best,

 

......................john




#60268 Hot Wax!

Posted by JBaymore on 08 June 2014 - 10:10 AM

 What matters is exposure levels.)

 

You are absolutely correct with that statement.  It is the CORE of toxicological study. 

 

However the real ISSUE in most artist's studios is that they have NO idea WHAT the exposure level is.  THAT is the reason to treat materials with great respect.  In many, many cases ... that respect will be overkill. 

 

And what produces "safe" conditions and works in one artists studio and studio practice... is not necessarliy going to be the same in another situation.  So one person's experiential information may not hold up in another's world....and be misleading.

 

Those levels of contaminants relative to working practices can be studied (stuff like air sampling)....... most artists won't spend the $ to do that.

 

So we are then back to 'gun safety'....... is the gun loaded?  If you don't KNOW....... well.... you get the idea.

 

best,

 

..........................john




#60210 Bone Handles!? Help...

Posted by JBaymore on 07 June 2014 - 09:16 AM

Watch the demos yopu've found... then attempt to do this process about 500 times, being critical of each attempt and addressing the issues you see each time. You'll get it.

 

Seriously....... doing ANYTHING skillfully (like is evident in the handles above) requires the investment of a lot of time and effort. There are no "shortcuts" to mastery.

 

best,

 

................john




#60146 How I Process My Wild Clay

Posted by JBaymore on 06 June 2014 - 03:01 PM

I can add one thing in there in the early part of the process (unless I missed it).

 

VERY ealry on take a small sample of the clay and place an excess of vinegar onto it. If it fizzes all over, you have some calcium compounds (limestone / carbonate likely) evenly spread into the mix. That's generally OK.

 

If it fizzed from single localized little SPOTS....you have nodules of limestone in the clay. These will cause you what are known as "lime pop-outs". Almost impossibel t clean out of the body.

 

Find a new clay depsoit.

 

best,

 

....................john




#60065 What Is It You Are Really After In Your Work?

Posted by JBaymore on 05 June 2014 - 05:21 PM

I'm solely after the Big Bucks! ;)

 

best,

 

.......................john




#59881 Can You Double A Wood Burning Oven As A Kiln?

Posted by JBaymore on 03 June 2014 - 08:40 AM

Yeah.... wood firing is a "labor of love".  You REALLY have to be willing to accept the huge labor factor.  It comes in many forms.

 

First there is the "getting the wood" factor.  Whether that is tracking down good suppliers of cut stuff (whick seem to constantly be changing), or going out and cutting it and hauling it.... it takes time.

 

Then once you have it "on site", there is the wood prep itself.  The wood needs to be in certtain sizes.  Some larger , some smaller, and having the right ratio of those kinds on hand for a given kiln.  So likely some chain saw work, and then either hand splitting or using a log splitter. Often...... appropriate amounts of differnt types of wood too.... hard wood  vs. softwood, etc.

 

Then there is the wood stacking and "drying maintenence" aspects.  Keeping track of the condition of the backstock of wood for future firings.  Covering it at the right times.... uncovering it at the right times.  And so on.

 

Then ...... moving the current firings wood to the area near the kiln if it is not already there.  You get to be a kiln pilot.......... or actually .... "pile - it".  LOTS of "moving wood".

 

Next we have the loading of the kiln to factor in.  It is WAY harder to load a wood kiln than say a gas or electric kiln.  Between "strategic placement" thinking time as you are in there thinking about flame paths..... and then all the wadding issues.  WAY longer to load.  WAY, WAY, WAY.

 

Then there is the firing itself.  You need to stoke 24/7.  SOMEONE does anyway.  With a gas or electric kiln.... you can be doing other things at the same time as occasionally going and turning up a burner or two.  Or in the case of an electric kiln....... making sure the controller is doing its job.  Not so the wood kiln....... pretty constant attention.  As the firing progresses....... focus goes up.  All else fades into insignificance.  Nothing else gets done.  So every hour of the firing is at least oneperson labor hour... often more then one person on a larger kiln.  If you fire for 2 days...... one person.... 48 hours of direct labor at $X per hour in addition to all the other direct actual fuel costs.

 

Then there is the "firing exhaustion" labor costs.  Wood firing is hard physical work.  After a firing, you are drained...... useless for a while.  In some cases you are just finally SLEEPING!  So no pottery work gets done or far less than normal.  So in that sense... more "lost labor".

 

Then unloading.  Again a much slower process than gas or electric firings.  Cleaning ouit dry ash from fireboxes and waiting for dust to clear before you can really get in there.  Sometimes stuff is stuck and requires carefull thinking and judicious use of chizels and hammers or grinder to get out.   Older kilns have sharp bits and bobs that require slow careful deliberate  movements inside.... or blood is shed.

 

Then there is the clean up of the work.  Wadding and stuff like shells and the like removed. Deciding how MUCH to grind off.  Lots of grinding and buffing and fussing.

 

All in all........... HUGE amounts of labor.

 

For a lot of the labor above..... you can often contract it out.... but that still factors into the "wood firing is expensive" part.  When you need a "firing team" ..........and if you don't pay them cash to do so........... the expense there comes in the form of trading away part of that expensive kiln space (that you could have used yourself) for the firing labor others provide.

 

Yeah.... now that I've said all that.... I'm nuts.  Think I'll go get a couple big L+Ls with nice computerized controllers.  Sounds REALLY good to me right about now.  ;)

 

best,

 

.................john




#59871 White Spots On Bisque-Fired Brown Clay

Posted by JBaymore on 03 June 2014 - 07:15 AM

It is called "scumming". It is because there are some soluble salts in the clay body. They are migrating to the surface as the water leaves the clay and depositing there. On edges where the water tends to get air currents and evaporate first and best....... it tends to get concentrated.

 

Left unglazed it often still shows. Covered with glaze, it is a "crap shoot" as to how it will affect a particular glaze.

 

The FIX is done in the clay body formulation. If you are buying commercial clay...... you are kinda' stuck with that happening now and again. The typuical one is a TINY additiona of barium carbonate to the body (yes... barium carbonate). Thru ion exchange in the wet clay the barium carbonate becom,es insoluble barium sulphate ....and .... problem solved. Getting the precise amount of barium carb. is tricky. You don't want too much or too little. And it is a TINY TINY TINY amount.

 

best,

 

.................john




#59855 Odd Additions

Posted by JBaymore on 02 June 2014 - 09:40 PM

Denise,...... holy crap.... the mercury from the light bulbs....doubt if it all washed off !!!!! Not good.

 

I put TONS of stuff into clay bodies for 土あじ ..... Tsuchi Aji (Sue Chee Ah Gee)........ literal "Clay Taste" or "Flavor Of The Clay"......meaning "character of the clay body".

 

Sometimes there is ALL of the following in one of my clay mixtures: sawdust, granite dust and pieces up to 3/8", granitic sand from the river bank behind my studio, three sizes of commercial grog, molochite grog in two different mesh sizes, fine silica sand, coarse silica sand, crushed chunks of feldspar. And yes.... somtimes it does get thrown.

 

(Not as bad as you think.......but don't bear down heavily on the wheel head with the sides of you hands - you shouldn't anyway with any clay-. )

 

I have one clay mixture that is more rocks than clay. This idea was inspired by seeing a woodfiring potter just outside Mashiko in Motegi back in about 1996 or so. Some of his work more closly resembles glass than clay, as you can see through sections of the walls where the feldspathic rocks have melted. That mixture is a real bear to work with. Horrible to trim. And it takes about 6 to 10 repeated firings in my noborigama before the rocks melt down enough to not be used as a Surform Rasp. ;) :rolleyes: Lotsd of failures.... but the keepers are great.

 

I often have students at the college just go outside and dig up some "dirt" and put back into the commercial clay some of the character that the commercial "beneficiating" has so carefully taken out. :lol:

 

Don't be afraid to expeiment.

 

best,

 

...................john




#59756 Home-Made Kiln Question

Posted by JBaymore on 01 June 2014 - 01:52 PM

lincoln.jpg




#59337 Does Any One Else Miss This Nutcase?

Posted by JBaymore on 27 May 2014 - 05:26 PM

A while ago I was doing some kiln consulting work for a prep school with a good ceramics program.  (BTW..... I promised that this school must remain nameless when mentioning this following fact.)  There in a corner was a large maybe 5 1/2 -  6 foot tall piece.......... instantly UNMISTAKEABLE......... a still raw green Volkous "Stack".  I was blown away that it was there.  Nice one too.  That item is incredibly valuable........ and is just sitting there in their kiln room.

 

He had done a workshop there.

 

I love that old picture of Hamada, Leach, Yanagi, Archie Bray.... and Volkous at the workshop Hamada was doing.  And the comment from Hamada to Volkous, 'you need to loosen up' (see early Volkous pots).  He took it to heart.

 

best,

 

........................john




#59334 Kiln Ventilation

Posted by JBaymore on 27 May 2014 - 05:17 PM

Your issues are typically long term chronic exposures, not acute exposures.  Not much CO produced.  More SOx.

 

It is very simple to answer this question.  Get a Nighthawk digital readout carbon monoxide detector.  Put it in the kiln room.  Fire withouit the fan working at all or with the pipe enptying into th room.  Watch the digital readings.

 

If you CAN.... try to find an old Nighthawk sitting on the shelves of a smaller hardware store.  The newer untis have the sensitivity dropped so that the low level readouts are not as sensitive as they used to be.  But still good enough for that you are doing.

 

End of "hypothetical" discussion.  Then you'll KNOW the issue or not.

 

You can also get professional air sampling.... maybe $500 to do.  Overkill in this case.

 

Every kiln room should have a CO detector mounted in there anyway... particularly in a SCHOOL....... so this is not a wasted expense.

 

best,

 

............................john




#59104 Real-Time Kiln Advice (Kiln Curently Firing)

Posted by JBaymore on 23 May 2014 - 11:19 AM

I feell like I am running an online class here.........

 

If the flame front is seated ANYWHERE except in the plane of the front face of the retention nozzle narrowing flange, on the exterior (kiln) side of that plane,.... it is not burning where it should be burning by design.  Period!  End of story.  No metal burner is designed to have the flame burning inside what is called the mixing tube.  Basic combustion engineering.  Look it up in INDUSTRIAL references.

 

The video you shot clearly shows backburning unless there is some amazing distortion in the image.  The flame is burning inside the mixing tube.

 

The reason it is backburning is the relationship between the flame speed of the gas air mixture, and the rate at which that mixture is flowing out of the burner......and the inability of the retention nozzle to keep the flame seated where it should. 

 

Flame speed is the rate at which a flame front burns through a mixture of fuel and air.  Flame speed is determined by a number of factors. One is the particular fuel gas used. Another is the ratio of primary air mixed in with the gas. So flame speed is not a total constant.  It does vary a bit.

 

So............

 

Think of a canoe on a slow moving river.  If the canoeist is paddling upstream at the rate the river is flowing, relative to a point on the shore, the boat sems to just stand still.  This is when the flow out of the burner matches the flame speed exactly. (This only happens at one set ting for a give na gas/air mixture.)   

 

If the canoeist is paddling faster than the stream is flowing, he moves upstream.  This describes backburning.

 

If he is paddling slower than the river flow, he moves downstream relative to a point on the shore.  This represents the condition often known as "fluffing off".  The flame sort of "blows out".  Just before this happens... ther can be a gap of many inches between the burner nozzle tip.... and the burning gases.

 

All this above is a good analogy to bring to bear when thinking of how a burner is working.

 

Now you have to look at the kinetic energy flow that is mechanically induced by the flow of gas molecules coming out of the burner's orifice.  As gas molecules come out they "bump into" the air molecules occupying the burner's mixing tube.  This pushes them down the mixing tube.  This creates "space" and more air molecules come in the back of the burner to replace the ones moved away.... because nature abhors a vacume.   

 

Now when the potter tries to have the burner running at a low setting (to keep the kiln from jumping in temp and blowing up pots) the kinetic energy of the gas coming out of the orifice is minimal.  If that orfice also is relatively large to get he BTU volume of gas needed for later in the firing, and the pressure it is being ejected out is quite low, then the energy to 'bump into' air molecules is even more affected at the low settings.

 

When the burner is in this condition, the canoeist is paddling faster than that river of gas and air is flowing. 

 

THIS is where the retention nozzle is supposed to do one aspect of its complex job.  The main way it is supposed to do this is to cause flame quenching to happen right at the very large thermal mass of the tip of the burner. As the flame front is burning outside the burner nozzle and back toward the orifice in the mixing tube, when it reaches the relativelty cold mass of metal of the nozzle, that absorbs heat energy and stops the combustion reaction.  The flame can't burn back into the tube........ no energy present to sustain combustion. (There is another action that the nozzles do to help with this... which involves how the flow of material exists the slight narrowing flange at the nozzle ... more on this in a minute.)

 

So now we get into the aspect called "turn down ratio".  Every burner has one.  This deals with the range over which the burner and nozzle system can deal with the canoeist's actions.  It is the ratio between the maximum stable output of the burner, and the LOWEST setting that the burner can maintain a stable flame.  If you try to turn the burner's BTU output below the low end of that turn down ratio, the canoesit paddles faster than the river... .and the burner backburns.

 

On the other side of things, when the river is raging and the canoeist can't keep up with the flow, the nozzle's job again is to keep the flame seates at the tip.  There are a number of types of designs to do this, but what they all do is to try to slow down a small portion of that raging river, mainly by creating some eddy currents in the laminar flow through the center of the mixing tube, and keeping a small "ring of fire" seated at the nozzle tip.  This acts like a continous pilot burner to keep igniting the fast moving flow around the edges as it comes out of the burner. 

 

Some types of retention nozzles not only have a slight restriction plate (flange) in the nozzle to cause the eddy currents I mentioned (and also assist in flame quenching), but also have a set of small holes drilled in this plate.  This creates a small ring of individual stable little pilot flames to help do this job.  Looks a bit like the ring burners on a home gas stove.... and works on the same principle.

 

As the materials exit the burner tube, due to friction with the surrounding air (and kiln stuff) that starts to slow things down.... and the flame front eventually catches up with the velocity of the gases... and everything is now burning nicely.  This is why you often see that cone of nothingness in the center of the column of flame coming out of burners.  It is burning only around the edges.... but in the center it is still just gas and air mixture. 

 

If the kiln system is inducing draft, this complicates this further.  And resistance to gases flow (as mentioned in post above) near the outlet of the burner also can affect the flow out of the burner.

 

The better the burner,.... the better the turn down ratio.  The beter the burner, the better the retention nozzle properties.

 

The higher the pressure of the gas supply the more kinetic energy the gas molecuels exit with, the more flexibility you have for control.  And more ability to entrain % primary air.  The better the quality of the engineering and execution of the throat casting of the venturi on the mixing tube, the higher the percentage of primary air the burner can entrain....and again more conmtrol options.

 

As I said before.... the low pressure system is NOT helping you.

 

 

Burners are made of metal alloys.  The retention nozzle end of burners are made of specially formulated alloys that are intended to get relatively hot. They are also made in thick profiles, to help them not only cause flame quenching( to help with retention and specifically prevent back-burning), but tio also allow for some normal detrerioration and 'rusting away'.   

 

But like all metals, with heat and corrosive atmosphere, they eventually and slowly do deteriorate.  They are not "forever items".  The burner designers EXPECT certain situations to exist when they engineer the design of the burners for use.  It is expected that the nozzle area will be exposed to certain conditions.  It is ALSO expected that over time,....... becasue of the exposure to the heat energy.... those nozzles will deteriorate and eventually need replacement.  The amount of time this will take is based on the environmental expectations (planned life of the nozzle).  The hotter they get, the faster this deterioration will occur.  As they deteriorate, their retention qualities deteriorate.

 

Higher quality burners have better retention nozzles.  They do the 'retention job' better, and last longer.  You pay for this.

 

This is not "conjecture".  Or "opinion".  Ask a burner MANUFACTURER or design engineer.

 

With the PARTICULAR design of that kiln, the PARTICULAR circumstances you have described, and the IFB bag wall.... as I said it is possible that excessive temps may have damaged the burner nozzles.  I'll stand buy that statement also.  It is a good point that I was not remembering correctly that you had the burners stuffed up close to the kiln... so that fact certainly decreases the possibility. 

 

It does NOT impact what insulating firebircks can do to refractory temps when used in bagwall situations. 

 

I've seen lots of what by industrial standards would be called "poor practices" done by all sorts of 'experienced studio potters'.  It does not make them "correct".  I've seen lots of firebox area refractories un-necessarily deteriorated because of practices like using IFB for bag walls.  (For target bricks...... not so much of an issue.... full bag walls..... much more so.)

 

I stand by my statement that excessive heat can damage a burner retention nozzle.  I have pictures.  (Also have one nozzle out of four on my gas kiln that, at about 30 years, is showing its age ;) .)

 

I've taught this crap at the undergrad and grad level for about 35 years at MassArt, BU, and NHIA, and literally have built hundreds of kilns.

 

best,

 

.................john




#59035 Home-Made Kiln Question

Posted by JBaymore on 22 May 2014 - 10:05 AM

I feel the need to say that heating concrete above 300 C/575 F is a bad idea.  It can explosively spall and decomposes into caustic materials that react exothermically with water.  Its reactions to the gases of fire are also a big question mark.  I would feel terrible if anyone got a chemical burn due to heating concrete.

 

 

On facebook, Louis Katz just recently posted some images of the explosion (in Thailand) of a small wood kiln that was built on a concrete pad and the folks that built that kiln under-insulated the floor (common mistake).  Good solid orange color inside when it finally went BLOOEY!  LUCKILY no one was injured........ but the glowing mess and sparks and such made for some impressive pictures.

 

I've heard of a couple instances here in the US of that same thing happening with wood kilns improperly constructed on concrete foundations. 

 

Don't get serious kiln heat into concrete folks!  Bad things can happen.

 

The "root" cause of this mess.... the thing that "everyone knows".........  'Heat Rises'.  NO.... it does NOT.  Heat energy moves equally in ALL directions from areas of higher concentration to areas of lower concentration. (basic laws of thermodynamics)  If you decide you need X inches of some insulation configuration in the walls and roof of the kiln... then you need the SAME X inches in the FLOOR of the kiln. 

 

If the hot face of the roof bricks are at X degrees, then the same heat energy is leaking thru them as what is happening at the floor bricks hot face.  Simple really.

 

Hot gases rise when suspended in cooler gases........ hence our "experiential" core belief that "heat rises".  That nice heat from our woodstove seems to head for the ceiling of our homes.  It is the lighter hot air that is rising thru and above the cooler air.

 

best,

 

...........................john