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Pottery Knowledge Quiz Of The Week (Pkqw): Week 1 And Introduction/answers Included

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Keep posting folks, I'm glad to see the participation here.


Over the years, I have seen and heard a lot of erroneous information and skill development that could be corrected with some research reading. Case in point, just the other day I was watching someone throw Left handed on the wheel, he had reversed the wheel so that it was going clockwise. He was throwing by using his right hand on the inside, and doing pretty well with everything. However, he never seemed to be able to handle more than a few pounds of clay at a time. I was throwing, and he came in to throw next to me. He had 3# of clay, had reversed the wheel and was centering the ball. Left hand braced in to the hip, tight hand pulling inward. . . . suddenly it hit me like a brick. I finished my pull, got up and re-positioned his hands so that he was bracing with the right, pulling in with the left. He found it so much easier, he was amazed. I asked him where he had learned to do it that way. . .he said in college, but no one had ever told him he was doing it wrong! During the next week he was throwing 5-^# at a time, no problem. He had been muscling the smaller amounts on to center, but could not do the same with more. Made me feel pretty good that I could help him out.






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I went with vibration and sonic resonance because either would magnify any micro fissures in the glaze surface.  


I went with alumina on the saggar question: although it will probably end up being mullite. For the record however, you have to have high alumina in order to produce mullite in the body: so my answer stands!!!



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Here's mine. I'm 90% sure on #1. I am guessing on #2 since I've only read about saggars in a book or two and can't really remember much on it. #3 and #4 I'm 100% sure on. It will be interesting to see how many I get right or if I need to go crack a few more pottery books!


1) b. soluble salts

2) b. alumina (totally guessing)

3) b. alkaline detergents and water

4) c. insufficient drying of ware



Ps. This is great pres! What a neat idea I can hardly wait for the answers and for the next one!

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What a great idea! Thanks for doing this, Pres, and please keep on doing it. I would like to request however, that we come up with a snazzy title for this weekly quiz. Maybe something that turns into a funny acronym. I wish I could think of one, but imagination is often lacking in me. Come on group...help me out.

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Guest JBaymore

Pres said (heard a lot of erroneous information)

​This could be a question of the week

I have a few top add to that topic .


Oh yeah.  Erroneous information............. in online forums, in books, in magazine articles, in youtube videos, etc..  The list is long. 


The internet has made it worse than it used to be.  He or she with the loudest voice or the most repetition gets heard.  Quantitative over qualitative.


I always come back to the simple concept of "Vet your sources".  However, even that can be difficult.


I'll share something I talk about in my technical classes and have written in some handouts, that pertains to caveats about getting technical information.  This viewpoint is not "politically correct", nor will all like it.  But I think it is a very important subject to bring up with students.  Causes them to think critically.  (I'm re-writing this idea here... not copying the text from my handouts.)


There is this person whom we'll call, "Famous Ceramic Artist".  (Yes, I realize that "Famous" is a weird first name. ;)   Could be a man...could be a woman.  Don't know. Don't care.)  Famous Ceramic Artist makes STUNNING ceramic work.  Universally agreed amongst art critics and other ceramic artists alike........ this person is making some astounding visual work.  They exhibit in all the "right places".  They get featured in magazines.  They get pictures in books.  Heck, they WRITE books.  They do countless workshops "spreading their stuff".  They seem to be everywhere all the time.  They have throngs of "groupies" following them.  Life is good.


Remember... Famous Ceramic Artist became "famous" because of the nature of the art work they created.  BUT...... as a by-product of that fame, everything they say and do now becomes "ceramic gospel".


So when this person writes an article or a book or presents a workshop.... technical information usually gets shared. Potters love this stuff.  We are all about sharing the "tricks of the trade".  Maybe it is how kilns work.  How they fire.  Recipes for glazes and clay bodies.  How to fix defects in work.  Why clay is plastic.  How to control warping.  The list of possibilities here is long.  All of this information is taken as 'gospel coming from on high' also.  Because of course, they are "famous".


As Paul Harvey says ....... "and now for the REST of the story":


What you don't know....... and which does not in any way take away from the wonderful art work Famous Ceramic Artist produces... is that this MFA graduate of GKWU (God Knows Where University)......... got a D in their ceramic materials science class and also in their kiln building and firing class.  And that was a "Santa Claus" grade to boot.  You won't be able to find that information out easily or at all.  No one would talk about it....... because.... well.... they are "famous" now. 


So .... clearly stunning work execution......... technical information....... not so much.


It is VERY possible to be a total master of the things that you do in your own work, without having a broad based knowledge of lots of technical aspects of the craft.  We merely have to look at the amazing work of so many indigenous folk potters of days gone by,...... and know that they could produce amazing work.  But they knew little of the technical side of things outside their narrow area of expertise.  They were not trained in formal science.  And they might even be producing that work based on what that THINK they know... but making false attributions of cause and effect.  All they know is that when they do X........ they get result Y.  And result Y is what they want in the work.  It works to get the result ....... so it is all that is necessary to know.......and it must be true.


Sometimes even the Emperor has no clothes.


So.... again.......... vet your sources... carefully.  And look to MULTIPLE sources





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Guest JBaymore

Yes, even books can be erroneous. Imagine the editing that took place once the world was known not to be flat!






Wait!  Not flat?  :)


Which means that knowing the writing date and edition number is important when reading books to put them into some context.





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the worst books for errors seem to be the ones that claim to be the ultimate resource, the "bible",  the "complete", etc.   one had a simple heading wrong, C was reversed with F for the cone temp charts.  just a little mistake.

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Okay folks, here are the answers.  I am sorry to say, I am calling foul on the writer of question 3, or the answers for question 3 as someone was not thinking too well. Maybe we'll have to give him a good talking to. At any rate the answers are here, and if you redo 3 you will find that there are two options to correctly answer the question. Duh, my bad.


Week 1 Answers

  1. Egyptian paste is a single fired, high flint earthenware that develops its own glaze from ___________ _________ carried to the surface from evaporation.

    a. excess alumina

    b. soluble salts

    c. added bentonite

    d. sodium silicate

Egyptian paste is a single-ï¬red, high-flint earthenware,

which develops its own glaze from soluble salts (soda ash)

carried to the surface through evaporation.


  1. Clay saggars for multiple firings may be made using a clay body that is high in __________ to prevent warping.

    a. lithium

    b. alumina

    c. mullite

    d. earthenware

Saggars (which are stackable clay boxes that hold ware and

thus are typically used in place of shelves) must be made from

a clay body that can be ï¬red repeatedly while maintaining a

warp-free shape even under a significant ware load. They can be

made from a variety of clay bodies, but the ones containing

significant mullite are especially warp resistant and durable.



  1. There are no federal standards for labeling ware “dishwasher safeâ€, yet modern day dishwashers pose two threats to ceramic dinnerware.

    Physical attack caused by a combination of __________________________results in crazing.

    a. vibration and sonic resonance

    b. alkaline detergents and water

    c. high speed water jets and soak periods

    d. high heat and moisture


“What actually constitutes "dishwasher safe�

Nearly all stoneware and porcelain competently produced

by functional potters is “dishwasher safe,†in the sense that it will

not deteriorate or give off toxic quantities of harmful sub-

stances, but most potters ought to know more about the

subject. While there is no federal standard for labeling ware

“dishwasher safe,†automatic dishwashers pose two threats to

ceramic dinnerware:

The ï¬rst is a physical attack caused by the combination of

high heat and moisture, which may take its toll on relatively

porous bodies by causing their expansion and contraction. The

result is a crazed glaze surface. Vitreous porcelain or stoneware

is the most resistant to this problem, but if the body is

underï¬red or has significant glaze/body interface stresses, it,

too, may fall prey in the dishwasher to increased susceptibility

to crazing, chipping and shivering.

The second threat is chemical attack by alkaline detergent.

The harder, more completely melted and insoluble the glaze,

the more resistant it will be to dishwasher detergent. Higher ï¬red

glazes tend to be more resistant. Low-ï¬red luster glazes are never

dishwasher safe and eventually are dissolved by low-viscosity,

alkaline detergent. Matt glazes may be quite susceptible to dissolv-

ing, and earthenware matt glazes are the most suspect. Some

earthenware glazes can even become porous after repeated washing,

and any glaze that exhibits this quality should be excluded not only

from the dishwasher, but also from use with food.â€




  1. Many of us have been taught that wedging clay removes air bubbles that cause explosions, often dramatic, in the bisque fire. The true culprit for the “blow up†is __________________.

    a. poorly wedged clay

    b. poor uniformity of clay

    c. insufficient drying of ware

    d. bone dry ware


Most any time a pot actually blows up in ï¬ring, the culprit

is steam produced by water trapped in the wall.. . . .

When pots are completely dry before ï¬ring, steam is not a

problem. The kinds of blowouts . . . simply demonstrate the prior location of the water and the weak points the steam finally found to release pressure. . .


This weeks questions were taken from text in Answers to Potters Questions II, Ceramics Monthly.

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While there are other issues in defining "dishwasher safe", as per your discussion of the answer, if one carefully re-reads the original question, one finds that only option D addresses "crazing".

No reason to call foul on the author of the quiz (you). It is the responsibility of the "student" to carefully answer the questions as asked.

Respectfully submitted by another long time teacher.

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Yep Fred, complex issue. Alkaline detergents break down the surface, and the heat and moisture cause crazing. If looked at together, the two really will break down any immature glaze. At the same time how hard does glass have to be to survive the dishwasher. I have measuring cups that were made in the 70's that have a fog on them. This fog is not a residue, but an etch into the surface of the glass. At the same time I used to use matt glazes on my decorative pieces that would allow the decoration to show without reflection, too bad I used the same glaze on functional ware for a few years.  Complex issue.


Thanks for the waiver, but I am going to be much more careful. I really think this could be a great idea for the community, and want to do it right.





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No comments or replies about the answers to the questions? Any complaints about format of answers in this manner?  


Raising awareness of my knowledge base and yours is my main stimulus for this idea. I hope you find it helpful.




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