A book I have (Renovating Old Houses by George Nash) noted as an aside
in one sentence that plaster will only stay usable for around a year. I
just bought 100 lb. of plaster (50 lb. USG Struct-o-lite and 50 lb. USG
Diamond Veneer Finish plaster) and wonder if it will last longer if I
store it in air-tight containers and store in a cool location. When I
bought these last week I had no idea it wouldn't keep indefinitely. I
have a lot of plaster work to do, but may well not get around to 95% of
it for a year or longer. Anyone have experience with these things?
Thanks for any info.

Dan

Dan_Musicant writes:

wonder if it will last longer if I
store it in air-tight containers and store in a cool location.

Plaster will strike in the bag due to infiltration of humidity. It will
still be a powder that mixes up OK, but given enough storage time and
humidity before use it will have a final strength of a Ritz cracker.

I would think the cost of proper containers would approach the cost of the
plaster.

Most cost effective would be 5-gallon paint buckets with the O-ring lids,
with a sock full of calcium chloride as a dessicant.

Easy enough to do your own "lab" testing later to verify setting quality.
Make some cylindrical samples (cast in a pill bottle) now and when you plan
to use it. See if you find any difference in strength or setting time.
Better than wasting a lot of labor on material that turns out to be flawed.

Steady non-condensing relative humidity is more important than cool.
Warmer may make your RH lower.

On Mon, 28 Aug 2006 21:53:19 -0500, Richard J Kinch
wrote:

an_Musicant writes:
:
: wonder if it will last longer if I
: store it in air-tight containers and store in a cool location.
:
:Plaster will strike in the bag due to infiltration of humidity. It will
:still be a powder that mixes up OK, but given enough storage time and
:humidity before use it will have a final strength of a Ritz cracker.
:
:I would think the cost of proper containers would approach the cost of the
laster.
:
:Most cost effective would be 5-gallon paint buckets with the O-ring lids,
:with a sock full of calcium chloride as a dessicant.
:
:Easy enough to do your own "lab" testing later to verify setting quality.
:Make some cylindrical samples (cast in a pill bottle) now and when you plan
:to use it. See if you find any difference in strength or setting time.
:Better than wasting a lot of labor on material that turns out to be flawed.
:
:Steady non-condensing relative humidity is more important than cool.
:Warmer may make your RH lower.

Thanks for the post. I cut open the bags last week and put the plasters
in plastic bags, fairly thick ones mostly. But I got the idea shortly
thereafter to use some plastic buckets I have. These aren't 5 gallon
buckets but food service buckets I got from a fast food place. They gave
them to me free. They had 10 lb. potato salad in them and I got them
with the tops. I have 13 of them now, and can get an unlimited supply in
the future for free (I made an arrangement with another source.

I presume they will be air tight, but I think your admonisions are
advisable - dessicant and testing. I would never have thought of the
dessicant, and I wouldn't have done the testing without your suggestion.
However, like you say, it's really important that I not invest time and
materials into repairs that turn out to be crap.

Great ideas with the old pill bottles. I have a bunch of them, been
saving them for some good use, and this is sure one. Thanks again.

Dan

PS: Anyone know where I can get calcium chloride in quantity
economically? Thanks!

In article ,
says...

snip

Thanks for the post. I cut open the bags last week and put the plasters
in plastic bags, fairly thick ones mostly. But I got the idea shortly
thereafter to use some plastic buckets I have. These aren't 5 gallon
buckets but food service buckets I got from a fast food place. They gave
them to me free. They had 10 lb. potato salad in them and I got them
with the tops. I have 13 of them now, and can get an unlimited supply in
the future for free (I made an arrangement with another source.

Nice. I buy them at the BORG. Free is better. ;-)

I presume they will be air tight, but I think your admonisions are
advisable - dessicant and testing. I would never have thought of the
dessicant, and I wouldn't have done the testing without your suggestion.
However, like you say, it's really important that I not invest time and
materials into repairs that turn out to be crap.

Not to mention the work to tear out crap.

Great ideas with the old pill bottles. I have a bunch of them, been
saving them for some good use, and this is sure one. Thanks again.

It is a good idea. I may have a little grout and thinset to do
this with.

PS: Anyone know where I can get calcium chloride in quantity
economically? Thanks!

The better sidewalk/driveway ice melter is calcium chloride (read
the container, NaCl isn't a desicant). You should be able to find
it for $12is for a 50lb bag at the BORG or a bit more at a hardware
store. It's also available (for a lot more $$) at grocery stores
in the winter (too soon now :-( ).

--
Keith

On Wed, 30 Aug 2006 14:20:04 -0400, Keith Williams
wrote:

:In article ,
says...
:
:snip
:
: Thanks for the post. I cut open the bags last week and put the plasters
: in plastic bags, fairly thick ones mostly. But I got the idea shortly
: thereafter to use some plastic buckets I have. These aren't 5 gallon
: buckets but food service buckets I got from a fast food place. They gave
: them to me free. They had 10 lb. potato salad in them and I got them
: with the tops. I have 13 of them now, and can get an unlimited supply in
: the future for free (I made an arrangement with another source.
:
:Nice. I buy them at the BORG. Free is better. ;-)
:
: I presume they will be air tight, but I think your admonisions are
: advisable - dessicant and testing. I would never have thought of the
: dessicant, and I wouldn't have done the testing without your suggestion.
: However, like you say, it's really important that I not invest time and
: materials into repairs that turn out to be crap.
:
:Not to mention the work to tear out crap.
:
: Great ideas with the old pill bottles. I have a bunch of them, been
: saving them for some good use, and this is sure one. Thanks again.
:
:It is a good idea. I may have a little grout and thinset to do
:this with.
:
: PS: Anyone know where I can get calcium chloride in quantity
: economically? Thanks!
:
:The better sidewalk/driveway ice melter is calcium chloride (read
:the container, NaCl isn't a desicant). You should be able to find
:it for $12is for a 50lb bag at the BORG or a bit more at a hardware
:store. It's also available (for a lot more $$) at grocery stores
:in the winter (too soon now :-( ).

What is the BORG? I'm in Berkeley, CA. A Google search on BORG doesn't
seem to come up with anything. Is it like Lowe's and Home Depot? Thanks.

On Thu, 07 Sep 2006 21:29:43 GMT, Dan_Musicant
wrote:

[snip]


What is the BORG? I'm in Berkeley, CA. A Google search on BORG doesn't
seem to come up with anything. Is it like Lowe's and Home Depot? Thanks.

We are the Borg.
You will be assimilated.
Resistance is futile.

But what if we don't want to be assimilated?

That is irrelevant.
You are irrelevant.
You will be assimilated.

Dan_Musicant wrote:

What is the BORG? I'm in Berkeley, CA. A Google search on BORG doesn't
seem to come up with anything. Is it like Lowe's and Home Depot? Thanks.

Big Orange Retail Giant = Home Depot

a guess.

Dan_Musicant writes:

I cut open the bags last week and put the plasters
in plastic bags, fairly thick ones mostly.

Polyethylene bags are poor vapor barriers.

Anyone know where I can get calcium chloride in quantity
economically?

Swimming pool store.

On Wed, 30 Aug 2006 16:51:45 -0500, Richard J Kinch
wrote:

an_Musicant writes:
:
: I cut open the bags last week and put the plasters
: in plastic bags, fairly thick ones mostly.
:
:Polyethylene bags are poor vapor barriers.

Thanks.
:
: Anyone know where I can get calcium chloride in quantity
: economically?
:
:Swimming pool store.

Thank you. It doesn't snow here, so swimming pool water conditioner is
easier had than snow melter.

On Mon, 28 Aug 2006 21:53:19 -0500, Richard J Kinch
wrote:

:Most cost effective would be 5-gallon paint buckets with the O-ring lids,
:with a sock full of calcium chloride as a dessicant.
A pool supply place I'm talking to doesn't have it but they stock
calcium hypochlorite, which he says is a "pool shocker" or some such
thing. Is that a dessicant (i.e. OK) or do I want calcium chloride? TIA

Dan

In article , Dan_Musicant wrote:
On Mon, 28 Aug 2006 21:53:19 -0500, Richard J Kinch
wrote:

:Most cost effective would be 5-gallon paint buckets with the O-ring lids,
:with a sock full of calcium chloride as a dessicant.
A pool supply place I'm talking to doesn't have it but they stock
calcium hypochlorite, which he says is a "pool shocker" or some such
thing. Is that a dessicant (i.e. OK)

No.

or do I want calcium chloride? TIA

In my experience, an air-tight container is sufficient. No need for a
dessicant.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

On Tue, 05 Sep 2006 18:39:50 GMT, (Doug Miller)
wrote:

:In article , Dan_Musicant wrote:
:On Mon, 28 Aug 2006 21:53:19 -0500, Richard J Kinch
:wrote:
:
::Most cost effective would be 5-gallon paint buckets with the O-ring lids,
::with a sock full of calcium chloride as a dessicant.
:A pool supply place I'm talking to doesn't have it but they stock
:calcium hypochlorite, which he says is a "pool shocker" or some such
:thing. Is that a dessicant (i.e. OK)
:
:No.
:
: or do I want calcium chloride? TIA
:
:In my experience, an air-tight container is sufficient. No need for a
:dessicant.

The problem is that I'm uncertain if these containers will indeed be air
tight or not. I think they may be absolutely air tight, but I'd hate to
find out they aren't by having my plaster go bad, especially if I've
gone ahead and used it. I'll try to find a cheap source of calcium
chloride.

In article , Dan_Musicant wrote:
On Tue, 05 Sep 2006 18:39:50 GMT, (Doug Miller)
wrote:

:In article , Dan_Musicant
wrote:
:On Mon, 28 Aug 2006 21:53:19 -0500, Richard J Kinch
:wrote:
:
::Most cost effective would be 5-gallon paint buckets with the O-ring lids,
::with a sock full of calcium chloride as a dessicant.
:A pool supply place I'm talking to doesn't have it but they stock
:calcium hypochlorite, which he says is a "pool shocker" or some such
:thing. Is that a dessicant (i.e. OK)
:
:No.
:
: or do I want calcium chloride? TIA
:
:In my experience, an air-tight container is sufficient. No need for a
:dessicant.

The problem is that I'm uncertain if these containers will indeed be air
tight or not. I think they may be absolutely air tight, but I'd hate to
find out they aren't by having my plaster go bad, especially if I've
gone ahead and used it. I'll try to find a cheap source of calcium
chloride.

Haven't you been reading my posts? I've said at least twice that in my own
experience, putting it in an airtight container is enough. How hard is it to
find an airtight container? All I'm using is a five-gallon bucket and lid that
I bought at Lowe's for about $8, and it works _just_fine_. No dessicants.
No driers. Just a tight lid.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Dan_Musicant writes:

The problem is that I'm uncertain if these containers will indeed be air
tight or not.

Putting a dessicant in a leaky or permeable container just lengthens the
time the interior stays dry. Eventually the dessicant saturates and
becomes inert. In the case of a deliquescent like calcium chloride, it
turns into a nasty, corrosive goo. Thus the advantages to silica gel or
molecular sieves.

Dan_Musicant writes:

A pool supply place I'm talking to doesn't have it but they stock
calcium hypochlorite, which he says is a "pool shocker" or some such
thing. Is that a dessicant (i.e. OK) ...

No. Calcium hypochlorite is an elemental chlorine source. You don't want
that near anything or even inside the house.

You want calcium chloride. Any pool supply place will have that. Perhaps
they're too typically ignorant to know the chemical name. They might only
know it as some variation of the words "calcium hardness increaser." Look
on the bag or tub for a chemical ingredient.

On Tue, 05 Sep 2006 16:42:19 -0500, Richard J Kinch
wrote:

an_Musicant writes:
:
: A pool supply place I'm talking to doesn't have it but they stock
: calcium hypochlorite, which he says is a "pool shocker" or some such
: thing. Is that a dessicant (i.e. OK) ...
:
:No. Calcium hypochlorite is an elemental chlorine source. You don't want
:that near anything or even inside the house.
:
:You want calcium chloride. Any pool supply place will have that. Perhaps
:they're too typically ignorant to know the chemical name. They might only
:know it as some variation of the words "calcium hardness increaser." Look
n the bag or tub for a chemical ingredient.
The guy I had on the phone was far from knowledgable. Sounded like a
kid. He said to call tomorrow (which is today) and ask for his boss,
which I'm going to do right now...

I talk to him and he says they don't supply it. It's a place called HD
Pool and Patio Supply. I ask him for recommendations near me and he
gives me the name of a place that's around 15 miles from me. I think
I'll try looking up wholesale chemicals warehouses. I bought some
chemical some years ago from such a place and thought it reasonable.

In article , Dan_Musicant wrote:
On Tue, 05 Sep 2006 16:42:19 -0500, Richard J Kinch
wrote:

an_Musicant writes:
:
: A pool supply place I'm talking to doesn't have it but they stock
: calcium hypochlorite, which he says is a "pool shocker" or some such
: thing. Is that a dessicant (i.e. OK) ...
:
:No. Calcium hypochlorite is an elemental chlorine source. You don't want
:that near anything or even inside the house.
:
:You want calcium chloride. Any pool supply place will have that. Perhaps
:they're too typically ignorant to know the chemical name. They might only
:know it as some variation of the words "calcium hardness increaser." Look
n the bag or tub for a chemical ingredient.
The guy I had on the phone was far from knowledgable. Sounded like a
kid. He said to call tomorrow (which is today) and ask for his boss,
which I'm going to do right now...

I talk to him and he says they don't supply it. It's a place called HD
Pool and Patio Supply. I ask him for recommendations near me and he
gives me the name of a place that's around 15 miles from me. I think
I'll try looking up wholesale chemicals warehouses. I bought some
chemical some years ago from such a place and thought it reasonable.

Why bother, Dan? You _don't_need_it_. An airtight container is all you need.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

In article , Dan_Musicant wrote:
A book I have (Renovating Old Houses by George Nash) noted as an aside
in one sentence that plaster will only stay usable for around a year. I
just bought 100 lb. of plaster (50 lb. USG Struct-o-lite and 50 lb. USG
Diamond Veneer Finish plaster) and wonder if it will last longer if I
store it in air-tight containers

Yes, absolutely. In an air-tight container, it will stay fresh for a long time
(at least two years, in my experience, and I live in an area with fairly
humid summers).

and store in a cool location.

Temperature doesn't really matter that much. What's important is keeping it
dry.

When I
bought these last week I had no idea it wouldn't keep indefinitely. I
have a lot of plaster work to do, but may well not get around to 95% of
it for a year or longer. Anyone have experience with these things?

It's better to use your plaster as soon as possible after opening the bag, but
the stuff will keep a long time as long as you keep it dry.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

On Tue, 29 Aug 2006 01:57:23 GMT, Dan_Musicant
wrote:

A book I have (Renovating Old Houses by George Nash) noted as an aside
in one sentence that plaster will only stay usable for around a year. I
just bought 100 lb. of plaster (50 lb. USG Struct-o-lite and 50 lb. USG
Diamond Veneer Finish plaster) and wonder if it will last longer if I
store it in air-tight containers and store in a cool location. When I
bought these last week I had no idea it wouldn't keep indefinitely. I
have a lot of plaster work to do, but may well not get around to 95% of
it for a year or longer. Anyone have experience with these things?
Thanks for any info.


It will keep longer in an airtight container with dessicant, but
still not forever. Plaster is cheap. Give the excess to your kids to
play with.