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#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?





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#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.





#110945 Is it only me. . .

Posted by JBaymore on 04 August 2016 - 09:25 AM

Iron chromate (hexavalent chromium..... known carcinogen) colored slips/glazes are easy to convert to a far less concerning recipe.  Just add the proper molecular equivalents of red iron oxide and green chromium oxide.  Easy-peasy.  Looks the same.


However, I think that any risks to anyone from the firing of that slip or the handling of that ware before firing is minimal to non-existent.  If it is a "line in the sand" issue of no iron chromate in the studio........ well... I guess that is something that must get enforced to bolster a "follow the rules" culture.  But the exposure .... including intensity, frequency and duration aspects.... is nothing to worry about.


Handling the dry powder is another story.  But even then.... how much gets handled, under what conditions, and how often.


There is a lot of hysteria in the ceramics community about the hazards.  A huge portion of it comes from not really understanding the science side of things.  Simple concepts like parts-per-million, micron particle size, the form of the chemical (oxide, carbonate, sulfate, chloride, etc.), and so on do matter.  Yes... there are things to be concerned about.  But that means an appropriate level of concern.


Some folks are equipped with both the knowledge and the facilities to handle more toxic materials than others.   Like in a bio-hazard lab;  some staff working there are OK to work with the e-coli.... others are OK for working with the anthrax. 


Understanding the studio safety and toxicology side of the field of ceramics is just one more part of learning about the amazingly broad spectrum of working with clay.  If someone can't pull handles well...... most folks then work at getting better at that aspect.  So if you are weak on the H+S stuff (and the technical side to understand that aspect)........ make an effort to improve your understanding/skills there too.


Then you can appropriately evaluate for yourself which materials and procedures you are willing to work with, and which you are not, from a position of accurate knowledge. 


For people who are new to the field, and who would be expected to not know, those who are more knowledgeable do need to protect them from their lack of knowledge.  One route to that is to just BAN everything potential hazardous completely.  But a far better route, as soon as is practical, is to provide an accurate education on the subject.


I come back to this base concept all the time that everyone seems to want to ignore.  Clay dust is one of the more hazardous things that we are exposed to. It contains free respirable sub-micron silica.  Causes not only silicosis but also cancer.  Intensity, frequency, and duration are really important concepts in this one.  Comparing to the hazard of some dry iron chromate slip on some pots to be fired to the general dust issues in the average studio...... this is like comparing a firecracker to an A-bomb.  If you are concerned about health issues in your studio....... first priority........go after sources of clay dust in your studio.


Spend one day working in the studio that you keep a written diary of things you are doing that could get a little bit of clay dust into the air.  Once suspended in the air it typically stays there for over 24 hours.  Watch carefully for indications of this happening.   Sometimes you have to get the light 'right' to see it.   Snapping a dry plastic or wooden bat into place on a dry wheelhead....... poof.  Wiping your hands on the dry towel that wasn't really well washed out yesterday.... poof.  (Ditto for pants or aprons with dry clay.) Throwing down that slab on the dry table top....poof.  Moving used canvas cloth..... arrrrggggghhhhhhh ......poof.  Each one little in and of itself.... sum total potential impact on the air quality...... large.  You'll be amazed when you really start looking for this stuff.





#110907 Potters wheel comparisons

Posted by JBaymore on 03 August 2016 - 01:16 PM

I miss the days when Studio Potter Magazine would do impartial equipment reviews.  It was a service to the field.





#110723 Qotw: Are Our Expectations Too High?

Posted by JBaymore on 28 July 2016 - 06:29 PM

I have never accepted, nor will I accept that all "variables" in glaze firings are truly variables. Some yes, All no.


This is very true.  A lot of studio potters typically think that they have all the variables under control... but there are ones that have impacts that many don't even know exist.  Industry gets its consistency level by controlling as many variables as they can.  But even they have ones that are hard or impossible to control (at least economically) ...so they have some "gotcha's" sometimes also.


The "unknown unknowns" are the places that the "phases of the moon" solutions start to circulate in the studio pottery community. 





#110700 Qotw: Are Our Expectations Too High?

Posted by JBaymore on 28 July 2016 - 09:18 AM

I think to "re-frame" the idea behind the question I might add that it is not that expectations are too high (as Johhny K points out above), it is maybe that the level of work and time commitment that many individuals are willing (or not) or able to put in to achieve those goals/expectations is where the actual issue lies. 


Having goals, even somewhat lofty ones, is a good thing, and the power of positive thinking has always guided me and those whom I know who have achieved their goals.  But you have to follow through on what is necessary to reach those goals.  If for some reason you cannot follow through to the level required to meet the goals you have set for yourself......... then you need to adjust your goals to a realistically attainable level.  Otherwise, you'll be frustrated and unhappy.


That above being said, there ARE many factors in 'success levels'.  Some are things that, no matter how high we set our goals, we are unlikely to achieve.  Knowing this is what might be called "achieving wisdom".


I am a pretty good (snow) skier.  (Was better when I was a lot younger. ;) )  Started very young, had good instruction, and had parents (THANK YOU!) that supported that opportunity for me.  I lived near a small ski area....... which was basically in the backyard of my high school.  I skied every day in the winters.  Long story omitted here.......... that stuff lead me to eventually hold a professional certification in the snowsports teaching field that less than about 400 people in the USA also held.  Getting there involved skiing in situations and on terrain that most will never tackle..... and many grueling skiing exams. Physical training, equipment tweaking, nitpicking.


So.... were there any "Olympic dreams and goals" or something like that in my head?  Nope.  Why? 


I had the pleasure of skiing on a number of occasions with people whose names anyone familiar with Olympic level skiing (back in the day) would recognize.  Like Phil and Steve Mahre.  Alberto Tombo.  And so on.  The GAP between myself and many of those other 400-ish people I was a part of and the Olympic men and women was so amazingly HUGE, that the reality was apparent instantly on the hill when skiing with them.  Could I learn from them and make improvements...... of course.  Could I BE them?  Not a snowball's chance in *&^%.   Many aspects come into play with that fact. 


One is physicality........ to do the "job" well, your body has to be built to achieve such peak level performance in the specific field.  Another is the willingness to push that body....... to and even over the limits.  To literally take life and death risks.  To risk permanent injury.  I was not gifted with the perfect skier's body.  I did enough damage to my body in the pursuit of what I did accomplish... and was not willing to do more.


Another factor is the level of commitment that is required.  A whole life dedicated to achieving that single "standing on the podium" goal.  It becomes your total life.  Everything else slips by the wayside.  Not much of a life outside the endeavor.  I had other intersts that were important also (like clay!).


Another is opportunity.  I had good ones in my early development.  Most of the Olympic folks had great ones.


And so on.


The bottom line of understaning......... I was happy with where I was and what I had achieved.


So set realistically lofty goals for yourself... develop a plan to get to those goals.... and stick with the plan....... and you'll get there.


If you have not read this book.... "The Outliers" by Malcolm Gladwell ..............it is a worthwhile read:  https://www.amazon.c...l/dp/0316017930


Also this one......."Art and Fear" by Bayless and Orland..............:  https://www.amazon.c...g/dp/0961454733






#110678 Qotw: Are Our Expectations Too High?

Posted by JBaymore on 27 July 2016 - 08:44 PM

For SURE this is not about "the younger generation"... it is not an 'age thing'... it is attitudinal.  I see the same thing in ALL age groups.





#110622 Qotw: Are Our Expectations Too High?

Posted by JBaymore on 26 July 2016 - 08:31 PM

: there is just too many roads to be able to walk them all in one lifetime.



I have 100 lifetimes all planned out.  :)





#110592 Qotw: Are Our Expectations Too High?

Posted by JBaymore on 26 July 2016 - 12:17 PM

I'm with you there Mark.


Saw the same thing happening in the snow skiing field when I was still teaching that.  See the same tendency in the clay field.  See the same tendency now in XXXXXXX (fill in the blank).  The age of Instant Gratification


People tend to see others who are at the end of LONG and deep careers in a field... and have put in the time and study and heartbreaks and the dues... and they tend to want that after 5 years of work.


I love the trend being talked about by some in academia ... that undergrad college is too long.... we need to drop it to only 3 years.  ???????  Heck....... we can't get enough covered in the 4 years!!!! 





#110440 Trouble With Red

Posted by JBaymore on 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. 





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