search  current discussion  categories  techniques - cracking 

pug mill clarification/clay cracking/waste

updated tue 1 sep 09

 

mel jacobson on sun 30 aug 09


a couple of things.

does the stain from the pug mill make spots on
your final firing?
have you thought of using a different clay body.?

is this iron ox, or what?

and, it is important to realize that many of the
new white bodies being produced have a great deal of
talc. (cone 6, electric bodies)
it does not dry well and can S crack like crazy.

my apprentice just made a batch of pots with a B body..and
the handles just fell off the mugs. it made me smile...same old
same old. she uses my brown body and abuses the hell out of it.
adds handles on chalk like mugs and the handles just stay.
we speed dry pots..no cracks. change the body, and all
kinds of problems pop up.
she has to slow dry for days...under plastic.

she now has a mind set of `screw that white body, it is
really awful`....
no, it is a good body, just fine, but does not work like our
true tested, multi-purpose iron body. i have made the body
work for production, high speed...no errors. i want 100 percent
success. that is the best `green` you can have. no failure to
throw out, or re/fire.

fire fast
no cracks
glazes that work
easy to use, pots that sell.

that puts money in the pocket of the potter.

white bodies take gobs of time, lots of fuss, and that is great
for the potter that understands the process...and is willing to
put up with it. it is their aesthetic, and they will keep it.
we respect that.

`green` means good common sense for the potter. 100 percent
of your fine product comes from your fire.

i have fixed/advised at least 6 kilns this year.
people wasting thousands of btu's of fuel.
yet, they talk `green`. bs, they waste like crazy.
just don't know it. like one kiln i fixed...they fired for 18 hours,
like a 100 gallons of propane, (that would be about 200 dollars in
propane +)...and they did not have 200 dollars worth of pots in the kiln.
we fixed the kiln, fired in about 5 hours with 15 gallons of propane.
did a down fire, great pots.) of course i ask the question:
`did you read the plan?, why the changes, bag wall, bad chimney
with cracks, big flue? `
`wally at the jr. college said your kiln/plan would not fire that way`.
`who was right, me, the plan or wally telling you stuff from 1920 books?`
hmmmm.
waste. that is the enemy.
think of all the work to re/cycle and remake 100 mugs with handles
that fell off. man, i won't do it. i have clay that works for me.
a bit of work with the pug mill, some things to add like fine grog
and sand, use tim frederich's new ohio stoneware clay with the
re/cycle at 50/50. and, i don't add stuff that leaches.
just clay. but, inverting your pots and spinning them at 90 degrees
every hour
is just good studio practice. three fans on high. or out in the direct
sun for the afternoon. bisque fire a day later. no cracks or ruined handles=
.
( like getting up at midnight and seeing a light in my studio..young woman
alone, after a full shift as a waitress, finishing her pots before the day
is over.) she hated the college bs, she loves craft, craftsmanship and get=
ting
a job done...no mouth, no smarty pants/English accented
metaphor...just great pots.
she now has about 500 pots done since she arrived.
mel



from: minnetonka, mn
website: http://www.visi.com/~melpots/
clayart link: http://www.visi.com/~melpots/clayart.html
new book: http://www.21stcenturykilns.com

John Goode on sun 30 aug 09


Mel and all
I do not see the gray in the final firing so it does go away.
I make my own body. Thinking it was the bentonite that is gray migrating to
the sides of the machine was my first suspect.Over all I will just have to
live with it as I do not want to coat the inside of the machine.
There is always another body so that is what I will try next.
Does anyone want to share a recipe for a white cone 6 body they like?
Stoneware or Porcelain like
Ron helped me with one that I will mix next.But first I need to build a
small clay mixing glaze spraying room as the dust is too much.So a small
room with a fan on one end where the dust can go out to the field on not al=
l
over the studio.The end result should be worth the trouble, health and mone=
y
savings and clay quality control.
How do others mix their own bodies in the 50- 400 pound range?
I hope to use my cement mixer outside and then after it has aged run it thr=
u
the PP and de air it then use it.
Over all this has been full filling making clay!
Looking forward to any and all advice.
John Goode
watermarktile.com
handmadeceramictile.com

On Sun, Aug 30, 2009 at 9:35 AM, mel jacobson wrote:

> a couple of things.
>
> does the stain from the pug mill make spots on
> your final firing?
> have you thought of using a different clay body.?
>
> is this iron ox, or what?
>
> and, it is important to realize that many of the
> new white bodies being produced have a great deal of
> talc. (cone 6, electric bodies)
> it does not dry well and can S crack like crazy.
>
> my apprentice just made a batch of pots with a B body..and
> the handles just fell off the mugs. it made me smile...same old
> same old. she uses my brown body and abuses the hell out of it.
> adds handles on chalk like mugs and the handles just stay.
> we speed dry pots..no cracks. change the body, and all
> kinds of problems pop up.
> she has to slow dry for days...under plastic.
>
> she now has a mind set of `screw that white body, it is
> really awful`....
> no, it is a good body, just fine, but does not work like our
> true tested, multi-purpose iron body. i have made the body
> work for production, high speed...no errors. i want 100 percent
> success. that is the best `green` you can have. no failure to
> throw out, or re/fire.
>
> fire fast
> no cracks
> glazes that work
> easy to use, pots that sell.
>
> that puts money in the pocket of the potter.
>
> white bodies take gobs of time, lots of fuss, and that is great
> for the potter that understands the process...and is willing to
> put up with it. it is their aesthetic, and they will keep it.
> we respect that.
>
> `green` means good common sense for the potter. 100 percent
> of your fine product comes from your fire.
>
> i have fixed/advised at least 6 kilns this year.
> people wasting thousands of btu's of fuel.
> yet, they talk `green`. bs, they waste like crazy.
> just don't know it. like one kiln i fixed...they fired for 18 hours,
> like a 100 gallons of propane, (that would be about 200 dollars in
> propane +)...and they did not have 200 dollars worth of pots in the kiln.
> we fixed the kiln, fired in about 5 hours with 15 gallons of propane.
> did a down fire, great pots.) of course i ask the question:
> `did you read the plan?, why the changes, bag wall, bad chimney
> with cracks, big flue? `
> `wally at the jr. college said your kiln/plan would not fire that way`.
> `who was right, me, the plan or wally telling you stuff from 1920 books?`
> hmmmm.
> waste. that is the enemy.
> think of all the work to re/cycle and remake 100 mugs with handles
> that fell off. man, i won't do it. i have clay that works for me.
> a bit of work with the pug mill, some things to add like fine grog
> and sand, use tim frederich's new ohio stoneware clay with the
> re/cycle at 50/50. and, i don't add stuff that leaches.
> just clay. but, inverting your pots and spinning them at 90 degrees
> every hour
> is just good studio practice. three fans on high. or out in the direct
> sun for the afternoon. bisque fire a day later. no cracks or ruined
> handles.
> ( like getting up at midnight and seeing a light in my studio..young woma=
n
> alone, after a full shift as a waitress, finishing her pots before the da=
y
> is over.) she hated the college bs, she loves craft, craftsmanship and
> getting
> a job done...no mouth, no smarty pants/English accented
> metaphor...just great pots.
> she now has about 500 pots done since she arrived.
> mel
>
>
>
> from: minnetonka, mn
> website: http://www.visi.com/~melpots/
> clayart link: http://www.visi.com/~melpots/clayart.html.com/%7Emelpots/clayart.html>
> new book: http://www.21stcenturykilns.com
>

John Goode on sun 30 aug 09


Des
The PP only holds 50 pounds of dry material. Of course that shrinks when th=
e
water is added.
That is why I am looking into a mixer that will do 200-400 pounds at a time
that way I can throw 50 lb sacks in and not have to weigh as much as I do
now making the 50s.
Thanks for the advice.
John Goode

On Sun, Aug 30, 2009 at 5:34 PM, Des & Jan Howard wrot=
e:

> John Goode wrote:
>
>> Does anyone want to share a recipe for a white cone 6 body they like?
>> Stoneware or Porcelain like
>>
> It will depend on your materials of course,
> this is an analysis of a commercial Cone 6 'porcelain'
> CaO 1.5
> MgO 1
> K2O 1.95
> Na2O 1.85
> Fe2O3 0.1
> TiO2 0.02
> Al2O3 27
> SiO2 65.9
>
> Generic raw materials (do your own conversion)
> plastic white-firing kaolin 63
> potash feldspar 24
> silica 13
> + dolomite 4
>
> I don't use additives of any type, in any of our clay
> bodies, the water used is rainwater.
>
> Ron helped me with one that I will mix next.But first I need to build a
>> small clay mixing glaze spraying room as the dust is too much.So a small
>> room with a fan on one end where the dust can go out to the field on not
>> all
>> over the studio.
>>
> In the raw materials/crushing shed the jaw
> crusher/rolls crusher dust extractor has a booth
> attached for really filthy dust/ash work.
>
> The end result should be worth the trouble,
>>
> We wouldn't do it any other way!
>
> health and money savings
>>
> Even though we dig most of our raw materials locally,
> we cost each & every kilogram as if we had bought it,
> at commercial rates. So, on paper the clay bodies are
> the same prices as commercial products.
>
> and clay quality control.
>>
> Commercial bodies are generic, having to satisfy
> any/everybody. Example, if dry sanding/scraping is done
> high green ware strength is required. We don't touch
> our pots at that stage, so making & fired qualities are
> what we compound for. For any pooches screwed, the arse
> to kick is standing in the same room as myself.
>
> How do others mix their own bodies in the 50- 400 pound range?
>>
> Some materials from the bag,
> most materials & reclaims from the crusher.
> Blunger, filter press, pug mill or,
> dough mixer, pug mill or,
> dough mixer, hand wedge.
>
> I hope to use my cement mixer outside and then after it has aged run it
>> thru
>> the PP and de air it then use it.
>>
> I thought that was the idea of a PP,
> as a single process.
> Raw mats in, mix, de-air, out.
> Des
>
> --
> Des & Jan Howard
> Lue Pottery
> Lue NSW
> Australia
> 2850
>
> 02 6373 6419
> www.luepottery.hwy.com.au
> -32.656072 149.840624
>

Des & Jan Howard on mon 31 aug 09


John
A cement mixer of the rotary barrel fixed blades type
won't mix clay to a plastic state. It may mix dry
materials, but no more. Dough mixers of various types
will mix clay bodies from dry powder to straight on the
wheel consistency. Our dough mixer, of ancient origin,
will mix up to 300 lbs of plastic clay.
Des

John Goode wrote:
> The PP only holds 50 pounds of dry material. Of course that shrinks when =
the
> water is added.
> That is why I am looking into a mixer that will do 200-400 pounds at a ti=
me
> that way I can throw 50 lb sacks in and not have to weigh as much as I do
> now making the 50s.

--
Des & Jan Howard
Lue Pottery
Lue NSW
Australia
2850

02 6373 6419
www.luepottery.hwy.com.au
-32.656072 149.840624

Des & Jan Howard on mon 31 aug 09


John Goode wrote:
> Does anyone want to share a recipe for a white cone 6 body they like?
> Stoneware or Porcelain like
It will depend on your materials of course,
this is an analysis of a commercial Cone 6 'porcelain'
CaO 1.5
MgO 1
K2O 1.95
Na2O 1.85
Fe2O3 0.1
TiO2 0.02
Al2O3 27
SiO2 65.9

Generic raw materials (do your own conversion)
plastic white-firing kaolin 63
potash feldspar 24
silica 13
+ dolomite 4

I don't use additives of any type, in any of our clay
bodies, the water used is rainwater.

> Ron helped me with one that I will mix next.But first I need to build a
> small clay mixing glaze spraying room as the dust is too much.So a small
> room with a fan on one end where the dust can go out to the field on not =
all
> over the studio.
In the raw materials/crushing shed the jaw
crusher/rolls crusher dust extractor has a booth
attached for really filthy dust/ash work.

> The end result should be worth the trouble,
We wouldn't do it any other way!

> health and money savings
Even though we dig most of our raw materials locally,
we cost each & every kilogram as if we had bought it,
at commercial rates. So, on paper the clay bodies are
the same prices as commercial products.

> and clay quality control.
Commercial bodies are generic, having to satisfy
any/everybody. Example, if dry sanding/scraping is done
high green ware strength is required. We don't touch
our pots at that stage, so making & fired qualities are
what we compound for. For any pooches screwed, the arse
to kick is standing in the same room as myself.

> How do others mix their own bodies in the 50- 400 pound range?
Some materials from the bag,
most materials & reclaims from the crusher.
Blunger, filter press, pug mill or,
dough mixer, pug mill or,
dough mixer, hand wedge.

> I hope to use my cement mixer outside and then after it has aged run it t=
hru
> the PP and de air it then use it.
I thought that was the idea of a PP,
as a single process.
Raw mats in, mix, de-air, out.
Des

--
Des & Jan Howard
Lue Pottery
Lue NSW
Australia
2850

02 6373 6419
www.luepottery.hwy.com.au
-32.656072 149.840624