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Member Since 06 Apr 2010
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#91966 Qotw: Do You Strictly Observe The Safety Rules In Studio?

Posted by JBaymore on Yesterday, 11:39 AM

Chris nails it (yet once again). 


Anecdotal evidence is suspect.  Be wary. 


When people get sick... they are always looking for a "reason".  Sometimes they make incorrect conclusions.  Another factor..... people who are sick often want to remain very private about it... and do not "advertise" that fact... so you don't ever even hear about it.


Also there is something called in the field "genetic predisposition".  Yup..... some folks can smoke 10 packs of cigarettes a day and also drink a whole bottle of whiskey every day... and die while skydiving at the age of 104.  Others can look at a certain carcinogen... and get cancer a few months later.  (We tend to hear about the former... not the latter.)  If you don't know your personal situation in that regard...... well....... it's a crap shoot. ("Do you feel lucky, punk?"  -Dirty Harry)


There is a LOT of information on this H+S stuff published.  Some highly technical.  If you haven't availed yourself of the information....  you still can.


The three easy to read references from my ceramic toxicology section I teach at the college:


Arist Beware  - Dr. Michael McCann


Keeping Claywork Safe and Legal  - Mononna Rossol


The Complete Artists Heath and Safety Guide  - Mononna Rossol



Chronic manganese poisoning is linked to a condition that very closely mimics the symptoms of Parkinson's Disease.... not ALS.


I personally know 5 potters that have diagnosed silicosis.  They did not work in mines, changing auto brakes, and other such known risk situations.  Likely cause.... ceramics related.  100% provable.... can't be done.


I also know one well known long term potter with diagnosed (and being treated) lung cancer (which also can be caused by inhaled silica exposure).  But linking that case directly to ceramics is not something that medical science is able to do with 100% accuracy.   Could it be related.... yes.  Could it NOT be related.... yes.


I've personally had a few ceramics related occupational health issues.  This stuff happens.  Nothing fatal...... so far....... I'm still kickin'. 


I'm very aware of the subject and take precautions in the studio.  Basic stuff is really pretty easy to do and be effective.  I do not "seal myself in a baggie".  I also do not throw dry clay and glaze chemistry around.  This is an important subject.... but there is a lot of "hysteria" that goes around in the community about it.


Get yourself educated. 





#91826 Qotw: What Do You Think Of Art Critique?

Posted by JBaymore on 01 September 2015 - 06:33 PM

In critiques I do at the college, using the words "like" and "love" are off the table.  Also the negatives of those terms.


We also focus on the fact that the word "critique" does not automatically imply a negative context to the process or the comments.





#91730 Liability Shift On Cc Coming Oct 1, 2015

Posted by JBaymore on 30 August 2015 - 11:02 PM

.............. which I try to not use because it reduces the young labor market drastically.


I also try to not use self-checkouts anywhere for the same exact reason.





#91685 Proper Reduction Firing Schedule

Posted by JBaymore on 29 August 2015 - 05:36 PM

There are many variables involved in developing specific cycles for specific effects with specific bodies and glazes..... but in general, the concept of "body reduction" as somehow being totally separate from "glaze reduction" is not quite accurate to what is actually happening. 


It is all a "blur" that runs together seamlessly. 


If you want to cause reduction effects on compounds in the body, you need to start reduction before the surface of the clay body or the surface of the overlying glaze layer becomes gas impermeable to the two prime reducing agents in firings; carbon monoxide and hydrogen.  Carbon monoxide is the main reducing agent in most of our firings because hydrogen at elevated temperatures is so reactive it usually "finds" available oxygen first in the kiln's gases. 


Note that carbon particles are SO large that they are quite non-useful for "reduction" in a kiln.  They don't easily get into the clay or glaze surface.  SO all that smoke some people get on gas kilns..... wasted effort. (Unless you are doing carbon trap shinos! ;) )


So the molecular size of the reducing agent getting into the clay is the first question in developing the firing cycle. As the body tightens, it does not allow the gases to get to the compounds below the immediate surface.  The main compound that we use to get "reduction" colorations in our work are iron compounds, reducing the valiancy to the black state from the oxidized red state.


FeO is a powerful flux on silica (SiO2) and which also happens to color the resultant glass at the same time.  So as the reduced iron 'bleeds' into the glassy phase of the body it also colors it (grey). This is particularly effective on small hematite nodules....giving lots of reduced iron in a small physical location (iron spotting). 


When the SURFACE of the tight body that is NOT under the glaze is then allowed to get in contact again with oxygen as the kiln is shut off and cooling, the surface turns to the reddish-browns we associate with "reduction" firing.  The body, if it is vitrified, is gas impermeable to oxygen ... and the inside it remains a greyish coloration. 


Importantly, the diffuse reduced iron compounds in the glassy phase of the body start to also work their way into the melting glaze layer over the already reduced body.  If the glaze surface starts to melt and become gas impermeable to the reducing agents before reduction had occurred, the body under the glaze does not get reduced.  So the interaction of the body with the glaze is less.  Plus the coloration of the body will be base on the red state (or the original state) of the iron compounds. 


Once the glaze surface is totally gas impermeable to the reducing agents then no amount of reduction will reduce stuff own inside the glaze layers or the underlying body (except maybe because of the bubbling of the glaze allowing some interior matter to be reduced on the surface). And once reduced inside, when the kiln is shut off and cooling and exposed to oxygen, the glaze surface also, just like the clay surface is oxidized.  Unless you fire down in reduction, or pump the kiln full of an inert gas (industry does this kind of stuff) the whole outside of "reduced" pieces is re-oxidized. 


Different glazes and different clay bodies have different firing characteristics.  There is no "one size fits all" firing cycle.  You have to find what gets the best out of your clay and glazes.  And different glazes and bodies often are not getting optimum effects when fired together in the same cycle.  What is great for one may be just OK for others.  We are back to that stock phrase of mine.... "test, test, test".


At one point I did some research on one particular celadon glaze on one particular body.  Over a LOT of firings it was determined that reduction at a certain intensity had to occur before cone 04 and after the kiln reached cone 4 it made absolutely no difference how the kiln was fired as to oxidation or reduction levels.  Reduction too low below 04 (cone 012 and down), and the body exhibited a tendency to carbon core and bloat and bleb.  Optimum turned out to be slightly oxidizing or neutral fire up to about cone 06 to 04 to start a light reduction, and that level was maintained at the same level until cone 4.  Then fired in slight oxidation to neutral to the cone 10 end point, then cooled in oxidation.


Some thoughts for ya' there.





#91681 Lead Glaze Recipes (No Safety Lectures Please)

Posted by JBaymore on 29 August 2015 - 04:53 PM

Jon Singer is a person you likely want to talk with. You likely will "speak the same language" at a technical level.


I use to use uranium compounds in salt glaze "back in the day".  Wonderful yellows and oranges.





#91668 Pc Members Juried Show

Posted by JBaymore on 29 August 2015 - 01:37 PM

Maybe now that I am not busy being on the Potters Council Board.... I'll remember to send in an entry for the first time in a number of years. :)


Thanks for the reminder Marcia.





#90608 Going Price Of Mugs

Posted by JBaymore on 10 August 2015 - 05:33 PM

 No worthwhile retail outlet is going to keep a line where the maker is selling to the public at the "wholesale" price.


A mistake too many people make.


The sort of "standard" way to look at this is that when you are MAKING pots.... you are a potter.


When you are SELLING pots... you are a retailer.


The Retailer BUYS the pots from the Potter at wholesale.  The potter should be happy with the price that he/she got paid for the work and well cover the costs, labor, overhead, and a profit factor. 


Then the Retailer adds the appropriate markup to the wholesale price they paid for the work they are now selling to cover the costs, labor, overhead, and profit involved in RETAILING them (and craft fairs and such ARE closely akin to retailing and DO have similar expenses to cover).





#90595 Going Price Of Mugs

Posted by JBaymore on 10 August 2015 - 02:20 PM

There is a lot to be thought about as one looks at potential target market and also what is known as price positioning.  And about assessing the available market or the target market.


It you do not have the ability to even reach higher end buyers... then making $1000 cups is going to an exercise in utter futility no matter HOW wonderful they are.  Conversely... higher end buyers likely will not be seriously looking at BUYING $10 mugs.  Simply because the artist does not think enough of their own work to price it appropriately.  So they will assume it is 'junk' from their point of view.


And if they even bothered to stop and look at them... and found them being something they would consider owning...... they likely would tell you right up front that you are absurdly underpricing........ and encourage you to raise the prices (thereby also raising the value of the $10 investment they just made ;) .) 


Matching the work to the venue and the market is key.  And pricing consistency.





#90467 How Often Do You Gear Up For A New Direction Or Experimentation In Your Work?

Posted by JBaymore on 08 August 2015 - 02:24 PM

For me it is "Darwinian".  Evolution... not revolution.  I don't "gear up"..... I just get my hands into the clay and listen.  Change happens over years.... not weeks or months.  Materials slowly change if or as the need of the pieces dictates. 





#90142 Going Price Of Mugs

Posted by JBaymore on 03 August 2015 - 11:09 AM

  If you want to make $20 per hour then you need over $30.00 per piece.  


The kicker problem here is that a skilled craftsman in other fields like a car mechanic, builder, and so on are looking at hourly rates in the $50.00 plus range (plumbers get more than brain surgeons ;) ).  Burger flippers get $10 an hour... and the move is on to make minimum wage $15.00 an hour.  Some places it is.


$20 an hour is NOT a good wage these days.


So if you are a long term and skilled craftsperson, you SHOULD be looking for at least $50 an hour.  Or well more if you are later career.


It is WAY easy to underprice for your skill set.  And when you price correctly...... your market narrows fast.





#90141 Going Price Of Mugs

Posted by JBaymore on 03 August 2015 - 11:04 AM

The "building the business" phase is no different than that experienced by just about ANY business.  The prime reason for the failure of new businesses?  Under capitalization.  You need to have a business plan that LOSES money for the first X years. 


Those "losing shows" one deals with in the early days of the business are part of that capitalization issue.  Eventually because you have done those losing shows.... you have honed the business to get into the winning shows.  Then the business goes from red ink to black ink.


Some call it "paying your dues".





#90139 How Much Do You Stay Within Glaze Limits?

Posted by JBaymore on 03 August 2015 - 10:55 AM

Well said there, patat.  Of course, I'd expect that from someone with the chem background like yours. 


The negative proof is the key, isn't it.  No simple answers.  The deeper you dig, the more nooks and crannies in the cave you find to delve into.


I use some lead glazed pieces for food also........ Japanese Aka Raku Chawan for tea ceremony.  I have inspected the gun ;)  and know it well. 


For many, many years I have been trying to get accurate information on the toxicological issues in ceramics out to people.  In the MIDDLE GROUND...... not the typical "we're poisoning everyone" hysteria....... and not the "I smoked 100 packs a day and drank 20 gallons of whiskey a day and I'm 83 years old" denial.


It's that old 100% correct ceramic answer adage....... "It depends.  It depends."





#90028 How Much Do You Stay Within Glaze Limits?

Posted by JBaymore on 02 August 2015 - 09:40 AM

Been doing a lot of reading today and found this. Fits in well with the topic of limit formula and where they arrived from. Interesting thoughts about B2O3 and if it's flux, stabiliser or glass former.




High Bridge Pottery,


Ahhh.... you now have officially headed "down the rabbit hole".  ;)


There is no end in sight.  "Resistance is futile".





#89961 Do You Store Your Glazes Dry Or Wet?

Posted by JBaymore on 01 August 2015 - 08:54 AM


Wet....30 gallon garbage cans.



How many glazes do you use? 5 glazes=150 gallon of material, 10 glazes=300 gallons.

WOW. you continue to inspire us slow polks.




In the large volume sizes.... 9.  Couple of small 5 gallon types also for some limited use stuff.  The 30 gal cans are  not dead full.... maybe kept at between 22 and 26 gallons in each.


I find nothing worse to freedom and spontaneity than trying to glaze with limited material or space.  I want to be able to pour, dip, trail and so on without "worrying".





#89682 Qotw: What Makes Something Qualify As Hand Made?

Posted by JBaymore on 28 July 2015 - 09:17 AM

Oh man........ "can o' worms".  Can't wait to see how this develops.