Marcia Selsor on wed 4 dec 02
Hannah,
If the release agent you used has petroleum in to such as a vaseline,
try heating it with a heat lamp. This happened to me when I was making
some large plaster from plaster shapes. I used vaseline. The heat lamp
working in about an hour. I heard the mold drop every so slightly from
the outside mold.
Good luck,
marcia in Montana
--
Tuscany in 2003
http://home.attbi.com/~m.selsor/Tuscany2003.html
Hannah Brehmer on wed 4 dec 02
Hi, Dear Clayart friends-
I decided to pour some plaster bats for a set of dinnerware I have to =
make. I gathered together various pie tins, etc. and coated them =
with a mold release - a kind I'd never used before. Usually I have =
used green soap liquid or plain vegetable oil, but this stuff was =
handy. Anyway, the metal pans were flexible enough that I could =
wiggle the plaster out, but two of them are nice glass pie pans and =
that plaster is stuck tight. I thought maybe if I let them dry out =
more they might shrink enough, but so far it doesn't look good. Maybe =
I will have to chip out the plaster, risking breaking the pans. I =
tried using the heat gun on the bottoms, but unlike metal, that glass =
doesn't seem to expand with heat. Does anybody have any helpful =
suggestions, or do I get out the chisel and do them over again?
It's so nice to have this resource to turn to at a moments notice!
Thanks,
Hannah
Jeffrey Francis Longtin on wed 4 dec 02
Hannah,
Heat isn't the key, water is. Water has a way of helping plaster release from
things that otherwise won't.
Suggestion: Put your plaster filled pie plate into a pan. Fill the pan with
water until it just comes above the rim of the pie plate. With luck the water
will seep in between the plaster and the pie plate and cause a slight
expansion of the plaster to occur. This SHOULD do the trick.
Take care
Jeff Longtin
James Bledsoe on wed 4 dec 02
i would try even heat like the oven or kiln the plaster can take 1000 f
and so can pyrex i think a couple of things might happen one the water in
the plaster (there is loads) will turn to steam and push the plaster out -
two the pie plate will expand faster thus release or the plaster will
expand faster and will pop out . now it may be that mold release is
working just fine and you have made such perfect castings that no air can
get in between the glass and plaster and all that is needed is a blast of
compressed air of course that is what steam is also.
j
----- Original Message -----
From: "Hannah Brehmer"
To:
Sent: Wednesday, December 04, 2002 2:40 PM
Subject: Help! Plaster won't release from the mold.
Hi, Dear Clayart friends-
I decided to pour some plaster bats for a set of dinnerware I have to make.
I gathered together various pie tins, etc. and coated them with a mold
release - a kind I'd never used before. Usually I have used green soap
liquid or plain vegetable oil, but this stuff was handy. Anyway, the
metal pans were flexible enough that I could wiggle the plaster out, but
two of them are nice glass pie pans and that plaster is stuck tight. I
thought maybe if I let them dry out more they might shrink enough, but so
far it doesn't look good. Maybe I will have to chip out the plaster,
risking breaking the pans. I tried using the heat gun on the bottoms, but
unlike metal, that glass doesn't seem to expand with heat. Does anybody
have any helpful suggestions, or do I get out the chisel and do them over
again?
It's so nice to have this resource to turn to at a moments notice!
Thanks,
Hannah
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
John Rodgers on wed 4 dec 02
Hannah, set the glass pie plates with the plaster aside until the
plaster dries. Then put them in the freezer. Often just the extreme
change in temperature will cause them to separate because the glass and
the plaster have different expansion rates.
If the plaster does not come out when really cold, run warm (not hot -
you don't want to break the plate) water over the back of the plate. he
rapid expansion of the glass against the still cold plaster should pop
it loose.
Don't do all this if the plaster is wet. The freezing of the water in
the plaster could break the plaster and plate both.
If all else fails, use a gouge - not a chisel with hammer - and gouge
the plaster out to the point it comes out. And it will come out. But
that is the hard way, to be sure.
Good Luck,
John Rodgers
Birmingham, AL
Hannah Brehmer wrote:
> Hi, Dear Clayart friends-
>
> I decided to pour some plaster bats for a set of dinnerware I have to make. I gathered together various pie tins, etc. and coated them with a mold release - a kind I'd never used before. Usually I have used green soap liquid or plain vegetable oil, but this stuff was handy. Anyway, the metal pans were flexible enough that I could wiggle the plaster out, but two of them are nice glass pie pans and that plaster is stuck tight. I thought maybe if I let them dry out more they might shrink enough, but so far it doesn't look good. Maybe I will have to chip out the plaster, risking breaking the pans. I tried using the heat gun on the bottoms, but unlike metal, that glass doesn't seem to expand with heat. Does anybody have any helpful suggestions, or do I get out the chisel and do them over again?
>
> It's so nice to have this resource to turn to at a moments notice!
>
> Thanks,
> Hannah
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
denise wright on thu 5 dec 02
----- Original Message -----
From: Hannah Brehmer
To:
Sent: Thursday, December 05, 2002 8:40 AM
Subject: Help! Plaster won't release from the mold.
Hi,
We've found that using the garden hose (highest pressure) water between the
edge of the mould and the rigid container often works well._ You'll get
wet too!!, but it's worth it when the mould comes out.
Denise______________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Tony Olsen on thu 5 dec 02
J, (James) has a good idea here, I would only add to put the pie pans =
upside down to allow gravity to assist while baking them in an oven. =
Try this before trying to dig out the plaster.
Tony Olsen
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D
i would try even heat like the oven or kiln the plaster can take 1000 f
and so can pyrex i think a couple of things might happen one the water =
in
the plaster (there is loads) will turn to steam and push the plaster out =
-
two the pie plate will expand faster thus release or the plaster will
expand faster and will pop out . =20
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Pat Southwood on thu 5 dec 02
Try hot water
Pat.
Neil Grant on thu 5 dec 02
If you can get to a compressed air gun that will often get to break the
vacuum created by the plaster excluding the air
Neil Grant
school of art
Dunedin NZ
>>> hannah.b@MINDSPRING.COM 12/05/02 11:40a.m. >>>
Hi, Dear Clayart friends-
I decided to pour some plaster bats for a set of dinnerware I have to
make. I gathered together various pie tins, etc. and coated them
with a mold release - a kind I'd never used before. Usually I have
used green soap liquid or plain vegetable oil, but this stuff was
handy. Anyway, the metal pans were flexible enough that I could
wiggle the plaster out, but two of them are nice glass pie pans and
that plaster is stuck tight. I thought maybe if I let them dry out
more they might shrink enough, but so far it doesn't look good. Maybe
I will have to chip out the plaster, risking breaking the pans. I
tried using the heat gun on the bottoms, but unlike metal, that glass
doesn't seem to expand with heat. Does anybody have any helpful
suggestions, or do I get out the chisel and do them over again?
It's so nice to have this resource to turn to at a moments notice!
Thanks,
Hannah
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
| |
|
