Phyllis Tilton on sat 6 jan 07
I have some plaster that has been stored in a plastic inside a fairly airtight plastic container. I will have need for some and wonder if I should or could dry this in some way if it has taken on any moisture. It is several years old.
If not, how to dispose of the plaster? Our community does recycle. One gets sensitive about what will go in a land fill. Several times a year, they have a collection of hazardous material---old paint, and things like that. Not sure what category ol plaster of paris would go in but that could be an option.
Phyllis Tilton
daisypet1
Charter Member Potter's Council
Ingeborg on sat 6 jan 07
Phyllis said ">I have some plaster that has been stored in a plastic inside
a fairly airtight plastic container. I will have need for some and wonder if
I should or could dry this in some way if it has taken on any moisture."
Phyllis,
You are not alone in wondering about old plaster. Throwing stuff out is a
problem, land fills etc. Someone said it is cheap and throw it out. Well,
pardon me, perhaps it is the German in me or the fact that everything has to
be trucked in to the hinterlands that it is not really that cheap, at least
not for me. In addition, when you order new plaster and have it shipped in
at no small expense, you really don't know how old it is. So.....
To use old plaster that doesn't work is, of course, no savings but....I have
wondered if one could calcine the plaster, would it be like new again or has
it changed chemically from absorbing moisture? Anyone out there know.
Ingeborg
3058 Stringfellow Road
P.O. Box 510
Saint James City, FL 33956
http://www.thepottersworkshop.com
Craig Clark on sat 6 jan 07
Phyllis, this topic has just come up on the list. Check the posting
from the last few days and you will find a good many suggestions. FWIW,
plaster is not a noxious or toxic substance. I wouldn't be overly
concerned about dumping some, depending on the amount of course. You
aren't talking tonage here are you? Ivor Louis had a very good
suggestion in adding small amounts of plaster into about a five gallon
water solution (I think) and pouring into the garden soil to help
floccullate a heavy clay concentration, which is something that we
suffer from around here. I'm pretty sure that if you contact him he will
be very specific about the procedure if you are adamantly opposed to
adding to your local landfill.
To check to see if the plaster is still good for casting use run
your hands through it and feel for little seeds of plaster. If you find
them then the plaster has reacted in some places to varying degrees with
atmospheric moisture and is not really good to use anymore. You can, but
your results may not be the greatest, even after you go through the
exercise of sieving out the seeds from the flour. I can't really say
much about drying the plaster in that I have never had the ocassion to
do so.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
Phyllis Tilton wrote:
> I have some plaster that has been stored in a plastic inside a fairly airtight plastic container. I will have need for some and wonder if I should or could dry this in some way if it has taken on any moisture. It is several years old.
>
> If not, how to dispose of the plaster? Our community does recycle. One gets sensitive about what will go in a land fill. Several times a year, they have a collection of hazardous material---old paint, and things like that. Not sure what category ol plaster of paris would go in but that could be an option.
>
> Phyllis Tilton
> daisypet1
> Charter Member Potter's Council
>
> ______________________________________________________________________________
> 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.
>
>
Snail Scott on sun 7 jan 07
At 06:43 PM 1/6/2007 -0500, you wrote:
>...I have
>wondered if one could calcine the plaster, would it be like new again or=
has
>it changed chemically from absorbing moisture?
Firing (or baking) to 350=BAF will=20
recalcine plaster.=20
-Snail
Megan Mason on sun 7 jan 07
=20
In a message dated 1/7/2007 1:48:49 P.M. Eastern Standard Time, =20
snail@MINDSPRING.COM writes:
At 06:43 PM 1/6/2007 -0500, you wrote:
>...I have
>wondered if one could calcine the plaster, would it be like new again or h=
as
>it changed chemically from absorbing moisture?
Firing (or baking) to 350=BAF will=20
recalcine plaster.=20
-Snail
Snail,=20
Any ideas or info on quantity and time involved/What judgement call would =20
you use to determine ''doneness"?Also, would doing this in the home oven be=20=
out =20
safety-wise for any reason?
Meg
Megan Mason on mon 8 jan 07
In a message dated 1/8/2007 6:06:40 P.M. Eastern Standard Time,
snail@MINDSPRING.COM writes:
I don't think it's worth the effort
to save a plaster batch gone bad,
unless your plaster prices are very
high. Your time is worth something,
and electricity, whether in kiln or
oven, is not free either
my last purchase of #1 MODELING PLASTER locally was $22.00,a couple years
ago. Is that high for 100# to you? At least now the supplier has the
supply undercover, which in the last location it was outside with a tarp.
Meg
Snail Scott on mon 8 jan 07
At 01:54 PM 1/7/2007 EST, you wrote:
>Snail,=20
>Any ideas or info on quantity and time involved/What judgement call would =
=20
>you use to determine ''doneness"? Also, would doing this in the home oven
be out =20
>safety-wise for any reason?
I've only done small batches, to=20
check for myself that it actually=20
works. A moderate soak at below=20
400=BAF but above 300=BAF is sufficient,=20
and could be extended for bigger=20
batches, but I can't tell you how=20
much longer it would take.
It turns out to be a great way to=20
clean off a glaze blunger that a=20
student had used to mix plaster!=20
I put the whole thing in the kiln=20
with an oven thermometer, and after=20
I pulled it out, I could just wash=20
off the previously rock-hard plaster=20
with water.
I don't think it's worth the effort=20
to save a plaster batch gone bad,=20
unless your plaster prices are very=20
high. Your time is worth something,=20
and electricity, whether in kiln or=20
oven, is not free either. As for=20
environmental concerns, you'd have=20
to balance the non-use of new plaster=20
which would have to be mined, against=20
the electical usage to save the old=20
stuff. Probably a net wash, I'd guess.
You can calcine plaster perfectly well=20
in a kitchen oven - the thermostat on=20
the oven is very convenient - but it=20
makes sense to me to keep the messy=20
stuff sequestered in the studio.
-Snail
Snail Scott on wed 10 jan 07
At 08:04 PM 1/8/2007 EST, you wrote:
>my last purchase of #1 MODELING PLASTER locally was $22.00,a couple years
>ago. Is that high for 100# to you?
Sounds OK to me. I used to get it
for $15, but that supplier quit
stocking it. Now I have to pay
Home Depot prices - twice as high -
or pay the gas and time to fetch
it from further away. I'd love to
pay $22.
-Snail
Megan Mason on wed 10 jan 07
In a message dated 1/10/2007 3:01:04 P.M. Eastern Standard Time,
snail@MINDSPRING.COM writes:
At 08:04 PM 1/8/2007 EST, you wrote:
>my last purchase of #1 MODELING PLASTER locally was $22.00,a couple years
>ago. Is that high for 100# to you?
Sounds OK to me. I used to get it
for $15, but that supplier quit
stocking it. Now I have to pay
Home Depot prices - twice as high -
or pay the gas and time to fetch
it from further away. I'd love to
pay $22.
-Snail
I guess I had bettered call them now to see what they are NOW, myself as I
see using some coming up soon.
Margaret
| |
|
