Plaster of Paris Unworkable After 7 Minutes.

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TomBrooklyn

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Every time I've tried to work with Plaster of Paris,  
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  [url]http://www.usg.com/navigate.d...roducts/prod_details/USG_Plaster_of_Paris.htm     [/url]           I find it's workability time limited to about 5 to 8 minutes.    It says 30 minutes on the bag which is the time it takes to set hard.     I usually am mixing up tiny batches of it for some minor repair spot.    

Is it normal for that stuff to only be workable for a few minutes though?
 
maybe your mixing it too thick, and if the background your applying it too is too porpus it'll suck the moisture out or the plaster too quick! try dampening the background with a brush, whart background are you applying it to btw?
 
Hi,
I did mix it thick.   I'll try again with a thinner mix.     It got hard before I even got it all out of the bucket so the substrate wasn't the problem.
Thanks.  
 
most likely just a case of mixing it too thick then, allways add powder to water
 
Actually, what happened was I added too much powder to the water and it got way way too thick, then I added more water to thin it back to "normal." Maybe that speeded it up a lot. Anyway, I'll try again, probably tomorrow. Thanks.
 
i thought plaster of paris was used to set a cast, if you've broken your arm leg or that sort of thing

why would u use it, dosn't make sence to me :-?
 
i thought plaster of paris was used to set a cast, if you've broken your arm leg or that sort of thing. Why would u use it, dosn't make sence to me  :-?
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I couldn't find any regular plaster the other day when I went looking for it. I finally located some at a building supplier in the next county, and I'll have to drive over there to get it.
 
Thats the way plaster of paris works mate,its a casting plaster,for molds and stuff,you dont use it in any way like gypsum plaster,you could mix it with holy water and it will still be gone in ten minutes,if your using it to patch cornice mix a small amount,pi$$ wet,maybe as thin as emulsion paint,{really!),let it set in the bucket,then you can work from that by scraping the surface.
 
robinson crusoe, just catchin up with this interweb thingy and theplasterin with the trowel thing and the bucket and the spreadingitallovertheplace.. ::)
we'd look right dingbats in america..'wot no multi finish?? no board finish?? no proper TEA!!!?? f'ck this, im off home, nevermekitpay... :('
;D
 
do you live on a little island or something
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No, but there's not much call for plaster around here, so it's not carried by the vast majority of building material suppliers.     I did remember another supplier just down the road who carries it though.   Going to be much more convienent to get now.
 
Thats the way plaster of paris works mate,its a casting plaster,for molds and stuff,you dont use it in any way like gypsum plaster
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Well that explains a lot. I'm looking forward to finding out how proper plaster works.
 
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