Jump to content


Member Since 06 Apr 2010
Offline Last Active Today, 10:17 AM

#112841 Ceramics Studio/woodshop Safety

Posted by JBaymore on 09 September 2016 - 11:06 PM

Welcome to the forums.


You've got a bit of a "tiger by the tail" there.  You have some potential professional liability if you know about the hazards and don't do something about them.... but if you "blow the whistle" it sounds like you'll be on the bad side of the faculty.  Not good.  And if you actually DO blow the whistle loudly so it can't be avoided to be heard in the ivory tower..... the admin folks will possibly try to fire you...... because it is expensive to fix this kind of stuff at an institutional level.


To whom do you answer in your position?  If it is the faculty....... you obviously have a real problem.  They'll make your life miserable.  Personally ..... I'd be looking for a different job from the sounds of this.


Sounds like there are likely OSHA violations all over the place.  You might have issues of the welding flare in the same space as people not working with that stuff and not wearing eye protection.  Light shields to stop that have to be in place.  Are all the guards on the power equipment?  Who does training for students and staff on the equipment?  How is that documented?


Has OSHA "Right to Know" training been done?  How about respirator fit training and medical monitoring? Are MSDS (now called SDS) books for all the materials used in the studios posted in appropriate accessible stations?  Are there eye wash stations where there need to be?  Safety showers near dangerous fire-y stuff?  How about stuff like fire blankets in hot working areas?  Fire extinguishers?  Is there local pickup ventilation on stuff like saws and grinding wheels?  Are all the corridors and walkways clear to the required distances?


Note that the safety issues that organizations like OSHA enforce do NOT apply to students.  Yeah... crazy, I know.  The rules apply to the people employed in the college.  Including you.  And you'll be in those spaces a lot of hours... so you are at risk from the mess more than the students. 


The OSHA and National Fire Protection Association websites are good resources.  And your head of the Facilities Department (or Buidings and Grounds) can possibly be your friend in all this.  Unless he/she is 'under the gun' also on this stuff.


Background ........ I used to be the H+S officer for our college, and chaired the H+S Committee for 9 years.  Been there, done that, bought the T-shirts.  And spent a lot of the college's money.


If they are putting that responsibility ON you specifically... then you have no choice but to address it.  Good luck.





#112588 Questions About Manganese In Clay, Slips, Etc

Posted by JBaymore on 05 September 2016 - 09:34 AM

There is a large level of misinformation in the studio pottery community about various aspects of toxicology of the materials we handle.  The key to negating this influence is getting good solid information about the subject.  There ARE good references out there....you just have to make the effort to find them.


Two huge assumptions that are both wrong:


  • Because it is art materials... it is all OK to handle.  It's art for crying out loud!
  • Oh my god, that stuff contains xxxxxxxxxx ..... we're all gonna' DIE!


There is a lot of misinformation in the studio pottery community surrounding manganese.  A lot of the studio pottery community has heard information about horrible events attributed to manganese that are totally apocryphal.  Meaning.... no proof.  Assumptions made.  There are good scientific studies that show that manganese has the capability to cause some serious issues.  But you need to understand the WAY that manganese enters the body, and the magnitude of the exposure that is implicated, and the extent of exposure that has to happen.


One of the most basic tenets for understanding toxicological impacts:  Intensity, Duration, and Frequency


Manganese dioxide ( the common form potters use) is not absorbed thru intact skin.  Skin contact is not an issue.


Respirable DUST is the main problem with manganese for studio potters.  And the main potential source for that problem is sub-micron fume dust particles from manganese vaporizing out of glazes, slips, and clay in the kiln. 


Respirable dust is the main problem for studio potters for just about ALL of the materials we use.  You want to have something to worry about......... it is SILICA dust.  Look it up.  It is not only about silicosis... it is about lung CANCER too.  Controlling clay and glaze dust in the studio is you number one priority.  Because it is sourced just about EVERYWHERE. 


If you control that problem appropriately (you likely cannot totally eliminate it) ........ then the smaller amount of dust containing manganese particles coming from manganese bearing slips, clay bodies, and glazes will also be decently controlled.


If you are not controlling the dust sources in the studio... then adding a manganese bearing source of potential respirable dusts is just compounding the potential issues.  You'll use less volume of manganese bearing slip to color the surface of the clay than you will if the whole (dust producing) clay body contains manganese.  So that is the better choice if both options give the eresults you want.  You'll also FIRE less mass of manganese in the kiln... thereby producing less manganese fume.  So that is the better choice.





#112433 Supplies To Buy When Buying A First Wheel?

Posted by JBaymore on 02 September 2016 - 09:07 AM

My preference is for wooden bats (when I use bats).  For probably 90% of what I make I simply pick them up off the wheelhead.  I often use a bat ON the wheelhead...... but it is there to make the working surface wood instead of metal.


Nerd... maybe get 1 each of a plywood one (I like Bailey's), a MDF one, and a plastic one... and see what YOU like.  When starting out....... it is good to learn how to pick up pieces off the wheelhead.  It is about skill acquisition and development at the beginning stages..... not the pieces themselves.


For smaller work... the Whisper is a NICE wheel.





#111958 Qotw: Epic Failures Anybody?

Posted by JBaymore on 25 August 2016 - 01:22 PM

A long time ago in a galaxy far, far away..............


I needed more of my custom clay formula mixed up.  Called up my handy-dandy long term supplier and ordered another 2000 pounds of it.  I had a show coming, a number of custom orders to complete, store/gallery stock to replenish, and so on.  I had already started production on the noborigama load a bit... but knew I'd be running out of clay any day. On the average I know that my wood kiln takes about 2000-2200 pounds of clay made into pots for a load....depending on the particular types of pieces for that load.


The clay arrives one day.  As the driver is unloading it I notice that the bags are labeled "Bateman" not "Baymore".  I ask the driver about that.  He says...... "Not to worry... just mis-labeled".  I say.,.... please call the factory and check on this to make sure it is my clay.  He does.  Gets assurances that it was just a mis-spelling of my name when the warehouse guy heard it and labeled the bags.  OK....... fine.


I continue working on the load.  At one point I am wedging together some of my OLD clay.. and some of the new clay.  As I slice the bung, I notice a SLIGHT marbeling of the clay.  Hummmmmm.............   Now I know enough about clay bodies that organics in the clays can cause slight color differences that have no bearing on the fired results.  That is normal.  Things like fireclays and ball clays (both were in that body) often look different run-of-mine to run-of-mine. 


BUT.... I flash back to "Bateman".  I call the supplier again myself.  Yup... it is the correct clay.  Yup... it's organics.  Yup...... not to worry.


Finished making and bisque firing the load and glazing.  Stacked the kiln.  Fired the kiln.


Unloaded the whole load into the shard pit.


I was NOT my clay formulation.  Probably was a cone 6 oxidation body.  Or a really botched mixing job with materials mis-weighed.  Just about nothing was salvageable in the whole load.  Looked terrible, slumping, warping, cracking, awful color... you name it... it had it.


This nearly bankrupted me.  Each firing of a large kiln like mine is a huge investment of materials and labor TIME.  LOTS of eggs in one basket.  Amongst the other stuff, I had one huge 12 place dinnerware set order in there for a very good client that was to be a wedding present..... missed the deadline.  Lost the purchase and the client.  Had no stock for general sales for a while.  Had used up a lot of paid-for materials.  Got zero dollars for my investment of all that time (time which simply can't be recreated).  Needed to spend more $ to get more materials to make more work.  Put production behind by one full kiln work cycle. 




SO....... I went to small claims court to try to recover something out of this mess.  Now the law says that I had to go to the court in the place where the company was located.  That was a couple hours drive away. I also consulted with a lawyer.  So there was more time and money invested.  My day in court finally arrived (weeks and weeks after he unloading).


And....................... I lost.


You know those disclaimers that the suppliers have on their websites and in their catalogs?  The ones that say "we are not responsible.... clay and glaze materials are naturally occurring minerals and we have no control over .... blah....blah.... blah".  Yup.... they are very powerful tools in a court of law.  They stand up.  Not only did I lose the value of the load... I had to pay for the clay!  Now the court DID allow me to not pay the INTEREST on the clay cost bill that accrued during the dispute.  Yay!


Lessons..... a multitude. 


The BIG one........... the phrase I use on this forum and in my classes all the time......... "test, test, test".


Do not put materials into full production until you KNOW that they are working correctly.


Also... trust you gut.  That should have lead me to .....test, test, test.  I screwed up.  I didn't.


The company in question... which shall remain nameless....... no longer exists.  They went out of business not all that long after this incident.  Guess maybe they had a lot more incidents like this.


There you have it.  Don't repeat my mistake.





#111949 Supplies To Buy When Buying A First Wheel?

Posted by JBaymore on 25 August 2016 - 09:50 AM

I'd put in my vote for a better wheel also for a totally new beginning thrower. 


If you are not looking to really make throwing a long term high priority in your clay adventures...... look for a used one... or a new Brent B or something like that.  You probably won't need "horsepower" or torque like even a Brent C ..... and you don't need to spend the $ for quiet of a Shimpo Whisper.


Check "The Potters Attic"  on Facebook for used equipment ads.  And Craigslist.  And anything your local Potters Guild / club might have.





#111947 Glaze Calculation Software Recommendations

Posted by JBaymore on 25 August 2016 - 09:28 AM


- include supplier and price details for materials





Insight does that.  Check the MDT options ... there is a place for you to put in the price you pay.  The price per pound for any glaze (if you've done that) is dis[played in the "data" area that shows stuff like Si:Al ratio, Mol wt, and so on.





#111774 Press Molded Tiles/trivets

Posted by JBaymore on 21 August 2016 - 06:31 PM

Have you looked at the pricing for commercial ceramic work in nice department stores?  Made mostly by jigger, jolly,hydraulic dry pressing, slip casting, and injection slip molding.  I would price them at what you think they should be priced as the quality of the OBJECT, as well as with a slight consideration for the COG aspects and the labor factor.  Just don't market them as "each made totally by hand forming".  If it makes you feel better, put "press-molded trivet" on the hangtag.  If someone asks how they are made... be truthful.  Simple.


Remember that "designers" get to charge a lot because ...well........ because they are "DESIGNERS".  But the objects sold are often totally machine made.  But it is good DESIGN of the object.  It is the design work that is the key.





#111717 Qotw: Are You Showing Us The Best Piece You Made When Starting With Pottery?

Posted by JBaymore on 20 August 2016 - 02:21 PM


Keep them coming folks........ this is interesting.






When do we get to see yours?



Will do for sure.  Wouldn't have asked it if I was not prepared to do this also.  Have to sort thru photos or old archived boxes of pots.





#111707 First Time Wood Kiln Fireing Questions

Posted by JBaymore on 20 August 2016 - 11:07 AM

John do you want ash build  in the fireboxes or would some ITC help there?


You want ash buildup pretty much everywhere.  Main firebox floor and the VERY lower side walls and the sidestoke firebox floors usually get washed repeatedly (zirconium/alumina works fine).... but since most folks stack stuff right in the fireboxes... nothing on the "above and around the work" area.


Typical anagama get better results with each firing as they "season". 


ITC does work for salt/soda... ...I've used it for clients..... and if it were a soft brick hot face I'd say for SURE coat it.  But not on hardbrick.  Talk to Fritz..... ITC 100 HT was not made for either hard refractories application OR for anything other than brand NEW IFB.  And yes... THIN coating is the answer with that stuff.  More ITC is NOT better.


Yes... the anagama kiln is slowly "dying" as the ash eats into the bricks and starts to melt the hot face.  Cost of doing business. 


From the woodfiring work I've done at the really busy woodfire place in Japan... we have a pretty good idea of the longevity of really good refractories in repeated long duration (4-7 day up-cycle) wood firings to cone 14.  A really good SK32 DP brick (about equiv. to US Super Duty DP) will last about 150 firings. 


My own noborigama here in NH looks to fit that number of firings model pretty closely also with good US materials.


So....... that kiln of Jawpot's will still last a while if it was built well.  About 25 years or so at 6 per year if they go hot and long.





#111467 Qotw: Are There More Male Or Female "well Known" Potters?

Posted by JBaymore on 16 August 2016 - 01:47 PM

The best student I ever had was a Japanese young woman who came to Rocky Mountain College in Billings and then transferred to Montana State Univ. Billings. Still friends.


One of our best NHIA under-grad grads ever was a Japanese woman, Chifumi Oi.  She came speaking almost no English (how she passed the TOEFL is anyone's guess).  Good thing I spoke some Japanese.  Amazing student and artist.  Incredible work ethic.  She had an undergrad degree in textiles in Japan before joining us.  Brought that influence to her hand-built claywork.  Went on to get her Masters in clay at RISD.  She's back in Okinawa now.  Still friends.  We've met up when I've been in Japan a couple of times.





#111330 Liability Of Making Lamps?

Posted by JBaymore on 13 August 2016 - 09:04 AM

 He says selling the lamp kits are out and suggesting what lamp kit to buy is out.  He says to market them as lamp bases and if anyone wants any more information about turning them into a lamp to send them to a lamp repair shop or to talk to an electrician.


Do you run every item you make thru your lawyers approval before selling?  What does he have to say about mugs, casseroles, teapots and the like?





  • Mug likes this

#111277 Going Gas, Need Some Direction

Posted by JBaymore on 12 August 2016 - 12:45 PM

You all love gas after you master it. 



Ah..... but beware the Dark Side.  WOOD firing!  MMmmmmuuuuhhhhhhaaaaaaaaahhhhhhhhhaaaaaaaaaaaaaa!  Electric leads to gas.  And gas leads to soda and salt.  And salt and soda lead to wood.  Take over your life, it will.





#111210 Going Gas, Need Some Direction

Posted by JBaymore on 10 August 2016 - 04:46 PM

Hi, so it's been awhile since I've been here on this forum. We've empty nested and moved to NJ from Mass. My studio contents have been in storage for the last 7 months. In a few weeks, I will have a house and a studio again! I have been taking classes at TASOC in Demarest to stay sane. I fell hard for the reduction look there. Since I sold my electric kiln before we moved, I am in need of a new kiln and plan to buy a gas kiln and fire to cone 6.


What I know:

There is a natural gas line right near the garage wall where I will set up (indoors). 

I will need the right size fitting to the kiln for the gas.

There is a high window that I can vent out of.

I probably will get a Bailey....


OK, that's it! ha ha not much.




-Can I bisque in the gas kiln?

-How much of the time during the firing do I need to be doing something?

-Will my cone 6 electric glazes look fabulous fired in reduction?

-Things to consider when shopping for the kiln? 

-Please recommend a good step by step book for firing with gas and reducing.

-I'd love to take a workshop but haven't seen anything.... have you?

-What do I need to know?

Thank you for any help!



attachicon.gif5Borg Teapot.JPG


Come see the reduction work I've done (but not fired myself) at Peter's Valley Craft Show Sept 24th and 25th!


You need to know the available pressure and VOLUME of gas that the gas pipe line and the meter leading to your property will accommodate.  The meter can be easily changed... the pipe cannot.  If you need more capacity than the pipe can handle... it is typically EXPENSIVE to get that kind of upgrade run.  You usually also cannot get the pressure changed easily if at all.  Your first step...... call the gas company.  THAT will tell you a lot about what the kiln CAN be.


Second......... check on your town's zoning and home business laws.  Make sure that you can actually do this.  If you sell your work... you are a business...even if you are not planning on selling out of that space.  This concept also leads to..........


Third, .....research your homeowners insurance situation.  Many will allow an electric kiln.. but not a gas kiln.  Some will allow an electric kiln or maybe a gas kiln for a hobby....... but not for a business.  Don't screw this one up.  You can maybe insure the whole property on business insurance... but that gets EXPENSIVE compared to the typical homeowners policy.


You are likely going to run into a lot of permitting and fire code stuff that you will NOT have with an electric kiln.  The Bailey and Geil units are AGA listed appliances... so that will help some.  Get to know the local building inspector and the local fire marshal.


You are probably not going to be able to vent out of that window.



-Can I bisque in the gas kiln?     Yes... remember everyone bisqued in wood and oil and then gas kilns before there were electrics.  In fact if you have good burners.. the potential for excess air is BETTER when bisquing in a fuel fired kiln than a static electric kiln... or even one with a downdraft vent.  The reason that electric kilns became popular for bisquing is computerized controllers.  They made what most consider a "drudge" firing simple.


-How much of the time during the firing do I need to be doing something?       You will need to attend to it frequently.... usually at LEAST every hour...for at least checking stuff like rate of climb and atmosphere and evenness.  Unlike the (bad) practice that so many do with computerized electric bisque firings (leave the kiln totally alone) .....you cannot do that with a fuel fired kiln.


-Will my cone 6 electric glazes look fabulous fired in reduction?        No way to tell this....every glaze is different.  And remember the "look" of reduction fire has more to do with the slow cooling of larger fuel fired kilns than the typical poorly insulated, low thermal mass electrics most potters use.  If you've been firing down in the past... you'll see some differences.


-Things to consider when shopping for the kiln?          The same consideration that went into your choices for an electric kiln in a lot of ways.  Both Bailey and Geil make good kilns.  The Blauu is the best on the market... but the price tag will kill you.


-Please recommend a good step by step book for firing with gas and reducing.      Unfortunately there is none.  "Gas Kiln Firing" by W. Ritchie used to be just OK.  Out of print now.  Olsen's "The Kiln Book" is certainly a helpful resource.  As is most any general ceramics book.  Best bet.... find someone to fire with and learn from them.


-I'd love to take a workshop but haven't seen anything.... have you?       If available, this is usually part of an undergrad curriculum in a college.  We take "special students" in my kiln (and glaze chem) classes.  Other institutions might also.  It is not often done in a short workshop setting... requires time and multiple firings to really learn much.


-What do I need to know?       Wow...... tons of stuff. Much too long to go into here... plus reading text and even looking at pictures is NOT the way to learn this stuff.  Find a local mentor.





#111061 Plasticizer/poreclain- Throwing Properties.

Posted by JBaymore on 06 August 2016 - 10:56 PM

I greatly prefer wet milled and blunged and filter pressed clay bodies.  Best way to get "good" plastic clay.  Which of course for tiles is amended to "bad" plastic clay. :lol:


Few to no US suppliers mix to slurry.  Tuckers does in Canada.


I've never yet made a porcelain pot that I am happy with...... with one single exception.  How I handle the aesthetics and the forms just does not "fit" in porcelain.  And I've not had the luxury of the time to spend to "find" my aesthetic voice in that medium.  I have one single porcelain yunomi that I made and wood fired in Japan that I have kept.  Oribe glaze.  The only porcelain piece that I have ever made and deemed even vaguely successful.


Gimme' a pile of gnarly, rock filled, non-plastic, large grained brown clay....... wet mix it....... and I'm happy B) .





#111053 New To Wood Firing

Posted by JBaymore on 06 August 2016 - 07:05 PM

A "manabigama" is the name for a specific very small anagama-style kiln designed by a specific person. (look it up.)  It is typically fired (by most people) for a shorter cycle than larger anagama.  Maybe two days.  Many large anagama are fired for 4 to 7 days.  While it can produce some very nice results, it is not known as a "heavy ash deposit" type of design.  The wares generally tend to be more "flashed" than "encrusted".  The pieces right next to the main firebox can get lots of ash... but further away.... much less so.  This has to do with the duration of the typical firing and also the size of the kiln and how that affects the draft flow.


For a manabigama style kiln I'd tend to do pieces with flashing slips added to "help" the kiln along.  Also use some American style high fire Shinos on some work.  Shinos are great in all kinds of woodfire kilns because they tolerate a WIDE range of cone endpoints, and simply do NOT run at all.  Most are fine from about cone 7-8 up to cone 14-15.  They take ash deposits nicely.  Many other high fire glazes can tend to run in extended multi-day firings even if the cone end points are the same as the typical 12-14 hour gas kiln firing.


A "woodfirer's trick":  On an unglazed form (even with flashing slip on the outside) put a liner glaze inside that is a high soda-ash shino.  The soluble sodium compounds in the glaze's water penetrate into the bisque and migrate to the outside also as the piece dry,.  This enhances flashing on the outside.


Watch out for lidded forms as a new woodfirer.  They have to be wadded very skillfully, and also not tend to warp due to design, forming, and clay selecdtion.  In extended firings, clay bodies that are fine at cone 10 in a gas kiln, can sag and move a lot over a multi-day firing.  This can cause the lid to slump down and make it not only not fit well (if you are lucky) but can also cause the lid and the base of the piece to come close enough to to each other in spots where the wadding is not... and fuse together from ash deposits.


Make yourself a couple of personal (gonna' keep em' for YOU) mugs.  Glaze the insides with a shino.  Decide on which side is the "face" (the side you want to be the focus).  Stack them face DOWN on their sides on scallop shells packed full of a refractory clay like a kaolin or a fireclay mixed with a lot of silica sand.  Set the shell holders on a little pad of the same kind of clay (like a sort of trivet).  Face the interior mug opening and the lip at a diagonal away from the flame path from the main firebox. 


When they come out do NOT try to immediately remove the trivet that likely will be stuck to the piece.  Place it carefully in a container of water.  That will cause the quicklime that the shells turn into (bad stuff....don't get it in your eyes) into soft goo and likely fully release the mug from the trivet.  If not tap judiciously until it does release.  Leave the mug in water after the trivet has released to continue to dissolve the remaining shell residue.  Lightly grind later with a diamond tool in a dremel to make it the w ay you like it..


You'll likely be happy.