3d mold making

"That guy went off on a press mold rant too, again, "

http://groups.google.com/groups?q=+c...dr=m&scoring=d

He's very, very badly confused. In three threads now.
Can anyone please help him out? His primary newsgroup is
alt.machines.cnc and his latest thread (it drifted - he's a drifty
guy)
is in "OT - Winger Bait".

Thanks,
--
Cliff

Bob Masta wrote:
On Sat, 17 Jul 2004 02:57:47 GMT, "Ed Huntress"
Snip
As you suggested, it's a press-mold job. But the molds don't have to
be plaster. He has an offer by someone else to machine them out of
another material.


The problem with any sort of machined mold will likely be that wet
clay is pretty sticky, and you will be using pressure to drive it into
the mold details. If the mold doesn't absorb any moisture, the
piece may not release. Some production press-molds use porous
molds that release the piece with air pressure, so in theory you
could machine a non-porous mold and then drill a bunch of
teeny holes in it. But plaster is a lot easier and cheaper!
You can make your originals in plasticine modelling clay
(the kind that never dries out) and just pour plaster over
them to make the molds. You don't even need a parting
compound. Or, have the machinst make models and
cast the molds from them.


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

Bob,
thanks for coming through with lots of info. I'm the original
troublemaker, and what began as a thought of trying slip casting in a
non-pourous material is now evolving into wanting to find out more about
press molding. Do you know of any good books on the subject? I would like
to read a little about it to see if it's the best choice for me. Machining
a pattern won't be a problem, and while one fellow has offered to cast and
fire them for me for free, I don't know how economical it will be in the
long run shipping them from Georgia to Washington. That, and when it comes
to how it's glazed, I don't know how hard I can push the free button. I'm
willing to bet he'd say no big deal, but favors shouldn't be abused.
The machinist group has a few folks who have come forth with a lot of good
information, but it's nice to see an outsider with some experience pop in
once in a while. I hope the ****ing contest didn't make you think we're a
bunch of idiots. Thanks again.


--
Later,

Charlie

Don't argue with an idiot; people watching may not be able to tell the
difference.

"Charlie Gary" wrote in message
...
Bob Masta wrote:
On Sat, 17 Jul 2004 02:57:47 GMT, "Ed Huntress"
Snip
As you suggested, it's a press-mold job. But the molds don't have to
be plaster. He has an offer by someone else to machine them out of
another material.


The problem with any sort of machined mold will likely be that wet
clay is pretty sticky, and you will be using pressure to drive it into
the mold details. If the mold doesn't absorb any moisture, the
piece may not release. Some production press-molds use porous
molds that release the piece with air pressure, so in theory you
could machine a non-porous mold and then drill a bunch of
teeny holes in it. But plaster is a lot easier and cheaper!
You can make your originals in plasticine modelling clay
(the kind that never dries out) and just pour plaster over
them to make the molds. You don't even need a parting
compound. Or, have the machinst make models and
cast the molds from them.


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

Bob,
thanks for coming through with lots of info. I'm the original
troublemaker, and what began as a thought of trying slip casting in a
non-pourous material is now evolving into wanting to find out more about
press molding. Do you know of any good books on the subject? I would
like
to read a little about it to see if it's the best choice for me.
Machining
a pattern won't be a problem, and while one fellow has offered to cast and
fire them for me for free, I don't know how economical it will be in the
long run shipping them from Georgia to Washington. That, and when it
comes
to how it's glazed, I don't know how hard I can push the free button. I'm
willing to bet he'd say no big deal, but favors shouldn't be abused.
The machinist group has a few folks who have come forth with a lot of
good
information, but it's nice to see an outsider with some experience pop in
once in a while. I hope the ****ing contest didn't make you think we're a
bunch of idiots. Thanks again.


--
Later,

Charlie

Don't argue with an idiot; people watching may not be able to tell the
difference.


Far and a way the best post I've read in a while. Good job Charlie.

Bill Roberto wrote:
Snip


Far and a way the best post I've read in a while. Good job Charlie.

Thanks, Bill. Every now and then......................


--
Later,

Charlie

The American Dairy Goat Association has competed with this promotion line:
"If God had wanted us to milk cows, He would have given us four hands."