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Member Since 06 Apr 2010
Offline Last Active Yesterday, 07:03 PM

Posts I've Made

In Topic: Trouble With Red

22 July 2016 - 08:51 AM

.............................. I can't even begin to say how much peace of mind doing so has given me.

I hope this helps answer some of the questions some of you might have in this subject. Getting your own stuff tested is the only way to know for sure.



Good for you! 





In Topic: Trouble With Red

22 July 2016 - 08:50 AM

One other thing I would do that I didn't see on the lab sites directions would be to wash the test piece that you are sending in with hot water and soap before sending it off. Have no clue if Cadmium would fume, doubt it though, but remember that thread John B posted from Carty about copper glazed pots leaching far less in the testing if they are washed first. Probably won't make a difference for Cd but not 100% sure.


Can't remember if I have ever mentioned this in THIS thread (not reading back now)... or anywhere here on the CAD forums.........


In Japan, the famous "Oribe" green copper glaze is loaded with copper.  One of the standard parts of using that glaze for Japanese potters (that is not all that well known here in the USA) is to take the pieces that are glazed with it and soak them in a solution made from crushed chestnut shells overnight.  Basically it is an acid bath.  It "clears" the hazy look of the glaze as it comes out of the kiln.  It is taking the "loose" copper off the surface and in the immediate surface layer of the fired glaze.


I also note that many "American" versions of "Oribe" greens are so loaded with copper that they cause little black microcrystalline surface silicate precipitations to form.  Those areas will be way less stable in holding the copper than fused glassy phase glaze.


The acid soak makes a huge difference in the look of the glaze. 





In Topic: Competive Juried Shows

21 July 2016 - 07:06 PM

Marcia and Bruce hit it.  WHY would you want to do them?  Aside from the "bragging rights" ;) . They can be an important portion of a solid marketing and business plan.  Or they can be a distraction from what you should be doing.  Depends on what you are making, and who your market is.


If you are going for the more "high end" market........ doing some of them for a good while is pretty much a "must".  If you are in or going into academia... it is a part of the evil "publish or perish" deal.


Sometimes getting a piece into the "right show" can be the event that 'opens the door' to a lot of other opportunities.


Most competitions in the USA are juried from slides.  Which is actually a problem.  Because it becomes "all about the photos".  The pieces have to POP in a purely visual environment.... when the juror is looking at the images for only a few seconds.  Hundreds and hundreds of entries.... for only a few pedestals and wall space.  Can be very competitive.  Some great subtle work will tend not to make the cut... and some mediocre work that photographs well will make the cut.  If you are going this route......  you either need a pro taking the photos... or you need to learn to take great images yourself.


You can waste a lot of money if your work is not at a competitive level with the level of the typical entrants to the competition.  This requires some seriously objective self-critique.  Match the "caliber" of the show that you enter to the "caliber" of your current work... to help assure some success and "payback" from your entry fees.


There is no "one size fits all" answer to this one.





In Topic: Ceramic Water Filter

19 July 2016 - 12:15 PM

You might want to contact these folks:  http://pottersforpeace.com/





In Topic: How Much Granular Manganese Dioxide?

19 July 2016 - 07:39 AM

The documented potential issues with manganese are via inhalation.  Manganese in clay bodies potentially increases your risks in two areas;  the respirable "fines" from the clay body DRY dust that invariable accumulates in the studio (the granules are not an issue) and mainly the fume that comes off the kiln in the firing.  A "fume" is not a "gas"... but is an ultra-fine, sub-micron "dust" particle.  VERY respirable and stays in the air a long time.


Then add the concepts of intensity, duration, and frequency to the equation concerning your possible "exposure".


This is not simple stuff.  That is why god created scientists, toxicologists, occupational health specialists, and ventilation engineers. ;)   There are only (to my knowledge) anecdotal individual pieces of information about potters getting manganese poisoning.  There are medically documented studies showing instances of industrial workers getting manganese poisoning.  They are NOT the same thing.  The industrial studies point to the potential risks...... but are not 100% applicable to what it is we do.  No one in the medical field has studied the impacts on studio potters (to my knowledge).   So we 'extrapolate' from the available info, and do the best we can.


Are we right to be concerned about the potential health impacts?  Of course.  Should we 'seal ourselves in giant baggies' to go thru life?  I think not.


Education, education, education.  The information about health and safety in the studio environment is out there.  Then you have to assess if you are a "glass half full" or a "glass half empty" type of person in your approach to life.


One of the important things that I tell people in my ceramic toxicology sessions and workshops...... if you have a health concern that you think is related to what you do in the studio, go get a referral from your primary care physician to an occupational health specialist.  The average GP type doctor is not typically trained to think about things the way that you need them to approach the subject.  Take a list of the materials that you use, and the MSDSs for them with you to both of your doctors. 


A lot of GPs will be surprised that you work with some of the stuff that you do.  If they KNOW about it, they will keep a little reminder in their head when they deal with your general health issues over the years.