Tempy Larew on mon 1 sep 03
I recently bought a Venco 4" pugmill, it was originally purchased in =
1983. The guy who owned it has made some modifications to the vacuum =
chamber. =20
I am having trouble getting all the air out of the clay. The vacuum =
pump is within 5kp of pegging out--so that is working fine--and the =
whole thing is sealed up tight-- could someone tell me what the inside =
of their vacuum chamber looks like? Do you use the screens or not? =20
I took the same clay and ran it through my old Bluebird 440, came out =
beautifully--so not a clay problem.
I have no instruction manual with this monster, as usual, I'm flying by =
the seat of my pants!!!
Any and all suggestions would be helpful. I have been trying to get in =
touch with Venco, but not had any luck. =20
Tempy Larew
Two Dog Pottery
Palmer, Alaska
Sorry to break the news, but fall is here.
Craig Martell on tue 2 sep 03
Hi:
I used to be a US Agent for Venco and I own a 4 inch that's the same
vintage as the one you have.
The advice you've already received has been correct but I'll add a few
things and this will hopefully help.
There are two stainless steel pieces that fit inside the deairing
chamber. One is a fairly flat plate that covers up most of the open area
between the deairing chamber and the inside of the barrel. The other is a
smaller, more vertically placed piece that fits against the upstream side
of the deairing chamber and is held in place by the larger flat
piece. When they are installed correctly, there's a small "slit" between
the two. Maybe 3/16s of an inch at most. This is at the upstream
side. This is the point where air is drawn out of the barrel into the
chamber. If these parts are absent, or have been altered, I would suggest
that you get replacements from Venco. Axner is pretty good at helping with
this.
The screens are very important for proper and good deairing. As Hank said,
they should be kept clean and free of debris. They shred the clay into
"noodles" so that deairing can be done effectively throughout the whole mass.
As far as the pump is concerned, you should be running at 85Kpa or more for
stoneware or earthenware clays and at above 90Kpa for porcelain. What kind
of Vac Pump do you have? Some of the older Vencos had Swan (brand name)
Pumps that were made in Brazil. They weren't the best that Venco has
used. If you have a Clisby 500 series, you've got the best.
One thing that causes bad deairing is not keeping the mill fed with
clay. The Vac Pump can pull air thru the hopper so you need to Cha Cha
when you are pugging or you lose Vacuum.
regards, Craig Martell Hopewell, Oregon
Laura Berkowitz on tue 2 sep 03
Hi Tempy,
My Venco may be similar to yours. I can't find my owners manual or I would
copy and send it to you; if I find it I'll contact you. I'll look further.
It has to be here somewhere.
It is possible whatever modifications he made are causing the problem.
If not, on mine, it is very important to keep the overflow chamber (area
with the clear plexiglass for viewing) clear so that clay does not plug that
overflow opening. If it does get plugged up, the clay coming out of the
nozel will contain air bubbles--at least on mine that is what happens. Most
overflow problems for me happen if I try to mix in clay that is too wet.
Another cause of overflow is if you press the handle and plate too hard to
force clay into the pug mill as it is pugging. Only put light pressure on
that inflow and let the pug mill pull the clay in on its own.
Also make sure that you have the liquid drained properly. There is a view
window on mine at the front towards the bottom. It has a red dot in the
middle and the level of oil should show mid-way on that red dot. If it is
higher (oil mixed with water) you must drain it to that level. Also, do
check to make sure the oil is at the proper level. The wetter the clay you
put through, the more you will have to drain.
Another thing to check--it will require you to clean out the front nozel
part--is whether or not your augers are working correctly. I have no
experience with what happens if they are not as of yet, but I did notice
when I took mine apart this last time (see para below) that the augers have
worn away the holes in the plate that keeps them in place. Not too much,
but enough so that I'm aware that plate may have to be remade at some point.
One caution since you are in Alaska, too. DO NOT let that pug mill freeze.
The casting is weak and it will crack. My Monitor oil stove has gone out
several times during extreme cold and I've already had to have the pug mill
welded twice. If you have to leave your studio for any extended time, empty
the pug mill as much as possible so the frozen clay can't expand.
Laura (Fairbanks, AK)
Tempy Larew
>I recently bought a Venco 4" pugmill, it was originally purchased in 1983.
The guy who owned it has made some modifications to the vacuum chamber.
>
>I am having trouble getting all the air out of the clay. The vacuum pump
is within 5kp of pegging out--so that is working fine--and the whole thing
is sealed up tight-- could someone tell me what the inside of their vacuum
chamber looks like? Do you use the screens or not?
>
Hank Murrow on tue 2 sep 03
Dear Tempy;
Pull the screen and make sure it is clean. I find that is the usual
problem.
Cheers, Hank in Eugene
On Tuesday, September 2, 2003, at 12:36 AM, Tempy Larew wrote:
> I recently bought a Venco 4" pugmill, it was originally purchased in
> 1983. The guy who owned it has made some modifications to the vacuum
> chamber.
>
> I am having trouble getting all the air out of the clay. The vacuum
> pump is within 5kp of pegging out--so that is working fine--and the
> whole thing is sealed up tight-- could someone tell me what the inside
> of their vacuum chamber looks like? Do you use the screens or not?
>
> I took the same clay and ran it through my old Bluebird 440, came out
> beautifully--so not a clay problem.
>
> I have no instruction manual with this monster, as usual, I'm flying
> by the seat of my pants!!!
Craig Dunn Clark on tue 2 sep 03
Tempy, I used a Venco for a number of years while I was in school. Ordered
and installed it way back in the eighties. Whenever there was a vacume
problem and the little gauge was pegged and the clay wasn't being de-aired
properly or the machine was working overly hard and not producing much mud
it was the result of either one or two things: the opening in the vacume
chamber itself beneath the plexiglass to which the vacume gauge is affixed
was filled with clay thereby preventing adequate de-airing......or......on
the main feed channel just past the the input area there is a "screen" that
helps to cut up the clay before it hit the vacume section of the mill (if my
memory serves me correctly.) It needs to be removed and cleaned
periodically.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
If you consult a book that is now sold again thanx to Axner which I believe
is titled "The Essential Potter" there is a set of plans that I think were
used by Venco for their mill (perhaps with a few modifications.) Vince has a
set of plans for a good mill as well.
----- Original Message -----
From: "Tempy Larew"
To:
Sent: Tuesday, September 02, 2003 2:36 AM
Subject: Venco 4" pugmill
I recently bought a Venco 4" pugmill, it was originally purchased in 1983.
The guy who owned it has made some modifications to the vacuum chamber.
I am having trouble getting all the air out of the clay. The vacuum pump is
within 5kp of pegging out--so that is working fine--and the whole thing is
sealed up tight-- could someone tell me what the inside of their vacuum
chamber looks like? Do you use the screens or not?
I took the same clay and ran it through my old Bluebird 440, came out
beautifully--so not a clay problem.
I have no instruction manual with this monster, as usual, I'm flying by the
seat of my pants!!!
Any and all suggestions would be helpful. I have been trying to get in
touch with Venco, but not had any luck.
Tempy Larew
Two Dog Pottery
Palmer, Alaska
Sorry to break the news, but fall is here.
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