jake willson on wed 4 jan 06
>Help please! I have an older Bluebird deairing pug mill (model 800) that
has always worked great. Recently
I am experiencing a LOT of air bubbles in pugged clay when I run it
through my slab roller. The cam
mechanism that keeps the slot to the barrel open is working fine (i.e.,
the slot is clear) and the vacuum gauge
registers between 20 and 25 inches as it always has. I can think of no
significant change in the clay I am
using or the way I am working, and I can't think of any reason the
deairing process shouldn't be working if it
is pulling a vacuum on the barrel - yet there is more air in the pugged
clay than if I use it directly out of the box
without pugging. Would greatly appreciate any insights.
Kathi LeSueur on thu 5 jan 06
jake willson wrote:
>>Help please! I have an older Bluebird deairing pug mill (model 800) that
>>
>>
>has always worked great. Recently
>I am experiencing a LOT of air bubbles in pugged clay when I run it
>through my slab roller.>>>>>>
>
For the best advice, call Bluebird directly. I've always found them to
be extremely helpful with questions.
Kathi
>
>
Ivor and Olive Lewis on fri 6 jan 06
Dear Jake Willson,
I am looking forward to the answers to your question. But how would you =
describe your clay when it is given the "Bend around the Finger" test ?=20
One thing that would concern me is the wide variation of readings that =
you are getting on your gauge. If it is close to 20 inches this is about =
one third of an atmosphere whereas 25 inches sounds more like one =
seventh of an atmosphere. From values that were given to my inquiry =
about the nature of the exhaust from a vacuum pump perhaps you are not =
drawing a deep enough "vacuum". You may need to get closer to 27 or 28 =
inches, less than one tenth of an atmosphere.
Given the nature of your clay perhaps you need to return to good old =
hand wedging.
There should be some interesting information out there.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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