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switching clay in my venco

updated wed 30 oct 02

 

Craig Martell on mon 28 oct 02


Jennifer axed:
>So you're saying the purge pug is the first pug of the new clay
>pushing out a barrel long length of old clay, yes?

Sort of! The first pug out is the "purge" clay. Just feed in the new clay
and treat the first pug that's the length of the mill from hopper to exit
as "purge" clay and use this clay for, shall we say, a less precise or
demanding application.

regards, Craig Martell Hopewell, Oregon

Jennifer F Boyer on mon 28 oct 02


Hi All,

This summer I switched from a light stoneware to a white
stoneware. I've been procrastinating on pugging the scrap from
the new clay. There is still old clay in my Venco. I HATE taking
the thing apart and have come up with this scenerio:
I pug the last few buckets of the old clay, and then add some
india ink to the last 10 pounds of scrap as it's going into the
pug mill. I then start adding the new clay. I can then watch for
the darker clay to come through and when it's out, I know that
I'm switched over to the new clay. Am I delusional? Will this
work, or should I just face facts and take the thing apart for a
good cleaning? The two clays are not all that different in
appearance when wet. But they act very different with my
glazes(expansionwise) and I have different formulations of my
glazes for each.
Any advice appreciated. I'm drowning in scrap....
Jennifer
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Jennifer Boyer mailto:jboyer@adelphia.net
Thistle Hill Pottery Montpelier VT USA
http://www.thistlehillpottery.com/

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Martin Howard on mon 28 oct 02


Venco need cleaning on a regular basis.
Then pug at a reasonable pace.
That screen in the middle is bound to get clogged up with use.

Now, if we could invent something to add to the clay which automatically
cleans the screen as it goes, that would be something to go for!!
Worth patenting it as well:-)

Martin Howard
Webbs Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
01371 850 423
martin@webbscottage.co.uk
http://www.webbscottage.co.uk
Updated 6th July 2002

Craig Martell on mon 28 oct 02


Jennifer:

What you are proposing is a fairly common practice. It's called
"purging". No big deal, especially if the bodies are the same firing temp
and pretty close to the same color. Measure the distance from the hopper
to the nozzle tip on the mill and run out a purge pug at least this long
and you're ready to go. Use the purge clay for Spitoons and Planters! :>)

If it's been a long time since you've cleaned the mill you might consider
doing this. I would recommend that you pull and clean the screens. If the
screens are functioning properly and not plugged or blocked you get much
better deairing.

Parting the barrel halves is the thing that folks hate the most about
cleaning venco mills. I'll tell you about a method I use that makes this a
lot easier. Take the screens out. Take all the bolts out that mate the
two halves. If there are two bolts the mate the flange behind the loading
hopper, remove them too so the halves can separate under inner
pressure. THEN, turn the mill on for a few seconds and let the clay
pressure from within part the barrel halves. This makes things easier,
quicker, and there's no prying of the soft aluminum barrel halves.

regards, Craig Martell Hopewell, Oregon

Jennifer F Boyer on mon 28 oct 02


Thanks Craig,
So you're saying the purge pug it the first pug of the new clay
pushing out a barrel long length of old clay, yes? I'm dense,
having only used one kind of clay for years . I've cleaned the
pug mill recently, but will pull the screens for good measure.
Nice trick re getting the barrel halves apart! Thanks.

Jennifer
Craig Martell wrote:
>
> Jennifer:
>
> What you are proposing is a fairly common practice. It's called
> "purging". No big deal, especially if the bodies are the same firing temp
> and pretty close to the same color. Measure the distance from the hopper
> to the nozzle tip on the mill and run out a purge pug at least this long
> and you're ready to go. Use the purge clay for Spitoons and Planters! :>)
>
> If it's been a long time since you've cleaned the mill you might consider
> doing this. I would recommend that you pull and clean the screens. If the
> screens are functioning properly and not plugged or blocked you get much
> better deairing.
>
> Parting the barrel halves is the thing that folks hate the most about
> cleaning venco mills. I'll tell you about a method I use that makes this a
> lot easier. Take the screens out. Take all the bolts out that mate the
> two halves. If there are two bolts the mate the flange behind the loading
> hopper, remove them too so the halves can separate under inner
> pressure. THEN, turn the mill on for a few seconds and let the clay
> pressure from within part the barrel halves. This makes things easier,
> quicker, and there's no prying of the soft aluminum barrel halves.
>
> regards, Craig Martell Hopewell, Oregon
>
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--
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Jennifer Boyer mailto:jboyer@adelphia.net
Thistle Hill Pottery Montpelier VT USA
http://www.thistlehillpottery.com/

Never pass on an email warning without checking out these sites
for web hoaxes and junk:
http://urbanlegends.about.com/
http://snopes.com
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*

vince pitelka on mon 28 oct 02


> Am I delusional? Will this
> work, or should I just face facts and take the thing apart for a
> good cleaning? The two clays are not all that different in
> appearance when wet. But they act very different with my
> glazes(expansionwise) and I have different formulations of my
> glazes for each.
> Any advice appreciated. I'm drowning in scrap....
> Jennifer

Jennifer -
You are not the least bit delusional, at least about this particular matter.
I can't speak about anything else! We NEVER take apart our Bluebird pugmill
to clean it out when changing claybodies. We just take the first four or
five pugs of the previous claybody, and when we run the next batch through,
we add a handful now and then from those first pugs, thereby distributing
the previous claybody evenly throughout the new batch. It makes little
difference. If you want to keep your new claybody more pure, then run a
hundred pounds or so of the new clay through the pugmill, and run the pugs
through again a few times, and then expel as much of that clay as you can
before you start putting your new clay through the mill. That intermediate
clay will be a mix of the two bodies, and will be perfectly good for
anything that doesn't have to exactly match the new claybody or the old one.
Best wishes -
- Vince

Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/