air pressure for casting

Sorry I don't have a number for you but I know there was a lapidary
Journal article on making and using a pressure caster. maybe less that 2
years ago? Anyway, try searching the index/archives over at ttheir website.
Also, the Karl Fischer/Pforzheim catalog lists a pressure caster, maybe
it lists a number for usage too?
let us know what you find OK?
Carl
1 Lucky Texan


Mike72903 wrote:
Assuming using air pressure for casting instead of centrifugal force or steam,
what would be an appropriate pressure to apply? 5 pound, 20, 100? Would a low
pressure result in a porous casting? Thanks, Mike in Arkansas


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to reply, change ( .not) to ( .net)

Seems to me that the atmospheric pressure that is applied during vacuum
casting is about 16psi. Should be a good place to start if you want to go
this route.

"Mike72903" wrote in message
...
Assuming using air pressure for casting instead of centrifugal force or
steam,
what would be an appropriate pressure to apply? 5 pound, 20, 100? Would
a low
pressure result in a porous casting? Thanks, Mike in Arkansas

Mike72903 wrote:
Assuming using air pressure for casting instead of centrifugal force
or steam, what would be an appropriate pressure to apply? 5 pound,
20, 100? Would a low pressure result in a porous casting?
Thanks, Mike in Arkansas

In http://www.fzk.de/imf3 they are testing different precision casting
methods with different pressure, perhaps they might give more Information.
My own knowledge says:
High pressure during casting process presses the metal faster inside the form.
Longer castingchannels are possible. The higher the speed the harder investment
is neccessary.
Normally, for jewelry casting a pressure difference of 0,5 to 1 atmosphere
is enough.
This has no influence in porosity.
Porosity is a wide area subject.
In some few cases only gas-porosity could be forced to smaller gasbubbles
by high pressure during cristallisation process.
--
Heinrich Butschal
Gutachten, Projektmanagement
www.butschal.de