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Plasticizer/poreclain- Throwing Properties.

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Most know all I do is tile, so plasticity in a clay body is something I avoid. However, I plan on learning that skill set shortly.

What plasticizer do you like for a porcelain clay body: V gum or Macaloid?

 

 

Nerd

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John:

I wonder when the clay arts are going to catch up with modern milling technology?

V-gum D is designed for rapid hydration, so the wait time for water absorption is past tense now.

Bentonite now have products that can be added to wet glazes, chemically coated to delay water absorption. (no gelling)

 

Nerd

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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) .

 

best,

 

...................john

D.M.Ernst likes this

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Nerd -- sounds like you already have your mind made up. And, given your quest for purity of additives, you will tend toward those items that have the fewest contaminants. Either will work. Will increase the cost of your porcelain, but that is your call. If you are looking for consistency in look from batch to batch, that is the way to go. If you can accept variation, the contaminants/impurities are the pathway. To me, clay is clay; one box may look a bit different, but that is okay. I like to throw a handful of feldspar into some bodies from time to time. Depends on what your final aesthetic will be.

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Bruce:

 

Not so much made up my mind, as narrowed down to two. Having read much, there are still some unanswered questions. Do either make the clay shorter, or longer? Never did find that answer in my search. Given the glaze I use, purity levels are almost mandatory if someone is going to try an attempt at production. Those beautiful crystalline pieces we see, represent the best in a kiln load. One in six or seven pieces turn out "stunning."  I am up to about 60%, and pushing for 85%. Even though I buy high purity materials, I still pay way less because they do not come through traditional sources. Its the age old adage: people do what works for them.

 

Nerd

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nerd, tom coleman is the porcelain guru for me and lots of other people.  he has a porcelain body mixed for him.  he said in the workshops i attended that it was hard to find a maker who did exactly what was asked in the recipe, 50 pounds of xxx not a bag marked 50 pounds of xxx.  the company was Aardvark.  i do not know if anything has changed since 2011 when i last talked to him about it.  his work is special, even to experts.

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yes, he mentioned that it was a very expensive ingredient but worth it when making huge amounts.  check out the website and ask, he is a really great guy and very helpful.

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TY Lady and Min.

 

I have several of Mr. Colemans recipes (note the MR <respect. ) I use his recipes in part as formula limits, a starting point for flux, silica, and alumina ratios. Ron Roy also suggested his work in our meeting in March. Had the pleasure of talking with Frank Tucker as well: Coneart and Tucker Clay. Also got to talk privately with VP of Aardvark Clay. Aardvark does use variations of Coleman recipes in several of their products.The recipe used at Alfred University is also interesting: which uses Macaloid.

 

Min, I suspect the food grade is either VeeGum D, or Veegum Pro: both used in foods and cosmetics. Both have rapid hydration properties, which would make it better for production. It is recommended that VeeGum T be hydrated hours before incorporating into clay: one of the reasons I am looking at the other two. They are both expensive: but only require 1-2% of batch weight. Although D and Pro grades are more plastic than the T grade.

 

Very much appreciate the input: the more info the better.

Nerd

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Nerd,

 

One way to "get around" the slurry method of making clay discussed by Prof Baymore is to age the clay.  Storing clay for several months after mixing (in say a Soldner mixer or Walker pugmill) will allow for migration of the water throughout the batch. 

 

Also bagging the clay in polyethylene bags and submerging the bags in a bucket (or tank) of water for a "some time" will allow the water gradients to equilibrate and limit the over-wetting.  That is how I rehydrate hard clay. 

 

LT

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LT:

Been thinking about that part of the puzzle for awhile now. My best solution is 5 gal. plastic buckets: the duct tape of any clay studio. If moisture content is 9-10: clay is considered moist. My idea was to pug at 10-11% moisture, and empty into 5 gal. buckets after each mixing cycle. Let them sit a week, and toss them back in there for use. If I with held a percentage of the silica: could throw it back in to firm it up. Not sure that will work, but it is my grand thought of the month. I have enough buckets to do a 7 day rotation. I believe 7 days is enough to hydrate. Thoughts?

 

Nerd

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My best clay clay was a blunged and filter pressed clay body. That was back when I used stoneware (70's and some of the early 80's) I have never used any Porcelain made that way but its the best way. 

Tom Coleman is very easy to talk to -I suggest calling him and asking about the specifics you want to know he is a down home straight talking guy. I have talked to him over the years a few times -never about clay bodies-more about glazes.I met him many years ago when he came to Humboldt State to do a workshop in the 80's.Back when I was a younger pup in clay.

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Mark:

 

Lady and Min made that suggestion, so I toured his website last night. Not been there before, not sure why. FPC clay is the best, but then you are dropping  ten of thousands for equipment. Perhaps I should study more under the masters of clay blending and start the Nerd Clay Co. Seems I enjoy experimenting and testing more than I do making. Then again I read dictionaries as a hobby. Merriam Websters- Dictionary of World Religions,  is a great read by the way. Would also recommend

Dictionary of Glass materials and techniques by Charles Bray. Recently translated to English: "Dictionaire de Civilazion".. French 1993

 

Joel: V-gum D and Pro actually inhibit bacterial growth, a side benefit of product.

 

Nerd

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Peter:

 

I noticed that reference in my most recent searches for info. No explanation per se, but very intriguing.

 

Ty Neil- looking for those who have used it for input.

 

Nerd

 

min-Lady: just fired off an email to Mr. Coleman: taking your advice. TY

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Check out the helmer clay body..... It uses a very lo wpercentage of vee gum...... And a " high tech" plasticizer. Dr-10 or drag reducer 10. It's quite plastic! I really like the feel and quality of this clay...... It's quite unique compared to the other porcelains I've experienced.

 

I have experimted with these plasticizers ....

My last test had les than extremely low percentage of platiccizer. Under 1/2 percent. Yet very plastic.. Would prefer to pm for further info

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I thought a vacuum pug mill did the same thing as a months ageing without the months worth of time. Maybe without the slight souring from bacteria.

I had the opportunity to try some vacuum clay compared to same body

 

blunged aged and filter pressed..... The later like john b stated is much nicer

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Lou:

 

I had looked at Helmer awhile back, something about iron content ( do not recall now.) Let me revisit that, TY.

 

From the notes I have taken: macaloid seems preferred in stoneware, and V-gum in porcelain. Not exactly set in stone rules, but I have noticed that preference.

 

Nerd

 

Edit: Lou, just hit me you stated 1/2%? Do you think V-gum is that much more plastic than macaloid?

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Lou:

 

I had looked at Helmer awhile back, something about iron content ( do not recall now.) Let me revisit that, TY.

 

From the notes I have taken: macaloid seems preferred in stoneware, and V-gum in porcelain. Not exactly set in stone rules, but I have noticed that preference.

 

Nerd

 

Edit: Lou, just hit me you stated 1/2%? Do you think V-gum is that much more plastic than macaloid?

its not the vee gum only    its the vee gum plus   DR-10  (drag reducer 10)    the helmer body has a work ability/feel to it

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If the body is well formulated, I don't have any problem with it being pugged and de-aired rather than filter pressed. I've never used filter pressed clays, only pugged, but I've never felt like I was missing out on anything. I think a crappy formula will still be a crappy formula no matter how it's mixed.

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If the body is well formulated, I don't have any problem with it being pugged and de-aired rather than filter pressed. I've never used filter pressed clays, only pugged, but I've never felt like I was missing out on anything. I think a crappy formula will still be a crappy formula no matter how it's mixed.

 

It does seem to make a considerable difference, at least to me. 

 

Example:  The clay I use at one place in Japan is totally un-useable if you simply mix it with water, wait a good while (like a month), wedge the crap out of it... wedge in some chammote (grog)... wedge it some more..... and then try to use it.  Bleh.  The three separate sieving and wet blunging operations followed by filter pressing and then followed by mixing at the plastic state in a bladed paddle batch mixer with the chammote...... followed by pugging (non-de airing) and it is simply the best clay I have ever used anywhere. 

 

Massively labor intensive though.  But the prices and demand for claywork in Japan support that added labor.

 

best,

 

.......................john

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