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Shelf life of plaster
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 |
Shelf life of plaster
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. |
Shelf life of plaster
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. |
Shelf life of plaster
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. |
Shelf life of plaster
On Mon, 28 Aug 2006 21:53:19 -0500, Richard J Kinch
wrote: :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. 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! |
Shelf life of plaster
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Shelf life of plaster
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. |
Shelf life of plaster
On Wed, 30 Aug 2006 16:51:45 -0500, Richard J Kinch
wrote: :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. 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. |
Shelf life of plaster
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 |
Shelf life of plaster
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. |
Shelf life of plaster
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. |
Shelf life of plaster
On Tue, 05 Sep 2006 16:42:19 -0500, Richard J Kinch
wrote: :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. 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. |
Shelf life of plaster
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Shelf life of plaster
In article , Dan_Musicant wrote:
On Tue, 05 Sep 2006 16:42:19 -0500, Richard J Kinch wrote: :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. 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. |
Shelf life of plaster
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. |
Shelf life of plaster
On Wed, 06 Sep 2006 16:29:41 -0500, Richard J Kinch
wrote: :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. I've spent an hour or two trying to locate CaCl2 hereabouts, but not done well. The pool supply places say they don't carry it and most are a ways from me, anyway. Chemical supply places are too expensive. I did find one that will sell me 50 lb. for around $55 including tax, so that's a possibility. But 50 lb. seems like a lot and I'll have to store IT somehow so it stays dry!! Pretty funny, in a way. I found some on eBay, 5 lb. for around $22 shipped. Maybe I'll do that. The CaCl2 is $10, the shipping $12. Or 10 lb. for around $32. I guess if I can keep it dry, it might be a good investment. |
Shelf life of plaster
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Shelf life of plaster
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Shelf life of plaster
Dan_Musicant writes:
The pool supply places say they don't carry it ... That's odd. It is a necessary ingredient to protect any plaster pool surface from soft-water etching. Maybe the pool supply places are in the replastering business, too. Another source is concrete suppliers, where it is used as an accelerant. I would also ask at an Agway feed store type place. Or just the 42 oz DampRid refill at Home Depot. |
Shelf life of plaster
In article , Dan_Musicant wrote:
It's hard for me to be certain that my containers are tight. I better do something soon, though, because I have the plaster in my garage and the rainy season is around the corner. On top of that, my garage needs a new roof! I'm gonna be a busy guy. Jeeeezzzzz.... Quit over-thinking this, and just go to Lowe's or Home Depot and buy the damn bucket and lid already. It'll be tight enough to keep your plaster from going bad. Worked for me over a period of several years. -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. |
Shelf life of plaster
In article ,
Dan_Musicant wrote: On Wed, 06 Sep 2006 16:29:41 -0500, Richard J Kinch wrote: :Dan_Musicant writes: ...snipped...: : The problem is that I'm uncertain if these containers will indeed be air : tight or not. I've spent an hour or two trying to locate CaCl2 hereabouts, but not done well. The pool supply places say they don't carry it and most are a ways from me, anyway. ...snipped... I didn't catch your location, nut if you live in an area that gets snow, you should be able to find CaCl2 pretty cheap, it's often sold as a deicer for driveways & sidewalks. I have to agree with the other poster who said that no dessicant is necessary, though. I keep small quantities of mortar mix, sakrete, etc. in old, cleaned 5 gal paint or drywall buckets, and haven't seen any go bad for periods of at least a couple-few years. If your just talking about a small box or bag of patching plaster or plaster of paris, you could also just put it in a heavy-duty zip lock bag. 3D 3D in old 5 gal paint containe -- Larry Wasserman Baltimore, Maryland |
Shelf life of plaster
On Wed, 06 Sep 2006 20:13:20 -0500, Richard J Kinch
wrote: :Dan_Musicant writes: : : The pool supply places say they don't carry it ... : :That's odd. It is a necessary ingredient to protect any plaster pool :surface from soft-water etching. Maybe the pool supply places are in the :replastering business, too. : :Another source is concrete suppliers, where it is used as an accelerant. : :I would also ask at an Agway feed store type place. : :Or just the 42 oz DampRid refill at Home Depot. I called HD, but they couldn't find it. Orchard Supply tells me they have calcium chloride in 26 oz. packages for $3.99. I think I may get a couple of those. Cheaper and faster than eBay. |
Shelf life of plaster
On Thu, 07 Sep 2006 19:56:36 GMT, Dan_Musicant
wrote: On Wed, 06 Sep 2006 20:13:20 -0500, Richard J Kinch wrote: :Dan_Musicant writes: : : The pool supply places say they don't carry it ... : :That's odd. It is a necessary ingredient to protect any plaster pool :surface from soft-water etching. Maybe the pool supply places are in the :replastering business, too. : :Another source is concrete suppliers, where it is used as an accelerant. : :I would also ask at an Agway feed store type place. : :Or just the 42 oz DampRid refill at Home Depot. I called HD, but they couldn't find it. Orchard Supply tells me they have calcium chloride in 26 oz. packages for $3.99. I think I may get a couple of those. Cheaper and faster than eBay. rice is pretty hygroscopic. |
Shelf life of plaster
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. |
Shelf life of plaster
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. |
Shelf life of plaster
On Thu, 07 Sep 2006 17:08:32 -0400, Goedjn wrote:
:On Thu, 07 Sep 2006 19:56:36 GMT, Dan_Musicant :wrote: : :On Wed, 06 Sep 2006 20:13:20 -0500, Richard J Kinch :wrote: : ::Dan_Musicant writes: :: :: The pool supply places say they don't carry it ... :: ::That's odd. It is a necessary ingredient to protect any plaster pool ::surface from soft-water etching. Maybe the pool supply places are in the ::replastering business, too. :: ::Another source is concrete suppliers, where it is used as an accelerant. :: ::I would also ask at an Agway feed store type place. :: ::Or just the 42 oz DampRid refill at Home Depot. :I called HD, but they couldn't find it. Orchard Supply tells me they :have calcium chloride in 26 oz. packages for $3.99. I think I may get a :couple of those. Cheaper and faster than eBay. : :rice is pretty hygroscopic. Yes, I always have some in my salt shakers. Would it make a decent dessicant? |
Shelf life of plaster
In article , Dan_Musicant wrote:
: :rice is pretty hygroscopic. Yes, I always have some in my salt shakers. Would it make a decent dessicant? While you're farting around looking for a dessicant which you don't even need, your plaster is sitting in its bag in your garage absorbing moisture from the air and getting ruined. I told you a week ago what you needed to preserve it. Buy the damn bucket and lid, and be done with it. -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. |
Shelf life of plaster
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. |
Shelf life of plaster
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