Chris Schafale on wed 28 feb 01
So, I finally got the parts for my new-old Bluebird 750, got the
corrosion sandblasted off the barrel, changed the oil, lubed
everything in sight, figured out that using clay that's tooo soft
doesn't work, and now have it pugging along happily. So, time to
try out the deairing. Hmm. Not deairing very well. Lots of tiny
bubbles -- I think someone described this as "frothy" clay. No
tensile strength at all, just tears. The clay I'm using is mixed white
stoneware scraps -- well aged, as they came from a community
studio where they have been accumulating for months or years.
What I can tell you is:
the rod and cam have just been replaced, as has the gasket on the
vacuum chamber cover.
the rod doesn't really work as it's supposed to -- tends to get stuck
when there's clay coming through, though works OK when the
barrel is empty
the compressor is quite new, and is more powerful than the
original, or so I'm told
the vacuum gauge rises quickly to 18 inches, but no farther
So, somebody help me out here -- what are the possibilities?
What should I look for/try? How much vacuum should I be
getting, anyway? Thanks for any insights!!
Chris Schafale
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
MaryBeth Bishop on thu 1 mar 01
Dear Chris,
Oh dear. What a project. When you are in de-airing mode can you lift the
glass top that has the meter on top? Sometimes mine doesn't seal tightly and
I have to clean the edges. I still can't imagine this could lead to your
problem so I am just sending moral support mostly.
Mary Beth Bishop
Ceramic Design Group on thu 1 mar 01
o
> What I can tell you is:
>
> the rod and cam have just been replaced, as has the gasket on the
> vacuum chamber cover.
Make sure you REPLACE the extension spring with a new one, and one that is
stronger. The rod needs to kick each time the cam comes around.
>
> the rod doesn't really work as it's supposed to -- tends to get stuck
> when there's clay coming through, though works OK when the
> barrel is empty
Make sure that the rod "bearing" is lubed and that the slot is clean with no
corrosion.
>
> the compressor is quite new, and is more powerful than the
> original, or so I'm told
DO you have a vacuum pump or a compressor? I assume it is a vacuum pump( can
also be used as a very low volume and pressure compressor). Do you have a
filter on it?
>
> the vacuum gauge rises quickly to 18 inches, but no farther
Check all connections, check the rubber gasket, and check the bolt and nut
assembly that goes through the wall of the vacuum chamber on top of the
mill.
>
> So, somebody help me out here -- what are the possibilities?
> What should I look for/try? How much vacuum should I be
> getting, anyway? Thanks for any insights!!
You should get between 20-26 or so inches of vacuum. Even small leaks cAn
degrade the vacuum.
It deos sound like the clay is too soft.
Call me if I can help you further.
Best
Jonathan
Jonathan Kaplan, president
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
voice and fax 970 879-9139
jdkaplan@cmn.net
info@ceramicdesigngroup.net
Plant Location:
1280 13th Street Unit 13
Steamboat Springs CO 80487
(please use this address for all deliveries via UPS, comman carrier, Fed Ex,
etc.)
"Custom design and manufacturing for the ceramic arts, giftware and pottery
industries. Molds, models, and tooling for slip casting, jiggering and
hydraulic pressing. Consultation on technical issues such as clay bodies
glazes, and kilns."
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