# Plaster: accellerator (Trade Secret)



## CarrPainting (Jun 29, 2010)

I was brought up, using accellerator in the base coat. it looks like rock salt, but has the feeling of kitty litter granules.

I was repeatedly told, using accellerator is a 'trade secret'.

you can either add it to the water, or, add it in on the mortar board. I havent got the ratios down, but I do know that it doesnt take much to make base coat set, rock hard... I once added a whopping table spoon to about 3 gallons of base coat and it was rock hard 15 minutes later.

I know the name of the chemical, but for the life of me cant remember what it is.

It allows you to apply that base coat, scratch coat, and finish coat, all in one shot. after each sets of course.

So for you plasterers out there, what is it?

I am gonna need more, thats why I ask. the jar I have is almost empty! :sad:


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## ohiohomedoctor (Dec 26, 2010)

Calcium?


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## Resta (Feb 11, 2009)

Natural remedies - salt and warm water.
Chemical - Plaster Fast Set, or Gold Bond.


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## MLCcarpenter (Dec 11, 2011)

I use aluminum sulfate with structolite quite often. Good for filling big gaps or slugging hollow metal frames.


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## Jason Whipple (Dec 22, 2007)

Plaster of paris always works for me. You can tool it smooth too.


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## The Coastal Craftsman (Jun 29, 2009)

The Trick in the UK was to throw a hand full of cement dust in a 1 gallon mix. i have no idea why it made it setup faster but you had about 15 mins work time before it went hard. for us it was only good to fill big deep holes in block walls and brick as it was workable for about no more than 10 mins.


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## Shellbuilder (May 14, 2006)

My plasterer uses cream of tartar (the spice). I have no idea why or for what. He plastered over an existing house for me today. My guess is he uses a lot more retarder than accelerator since most all of the work is one coat.


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## The Coastal Craftsman (Jun 29, 2009)

Shellbuilder said:


> My plasterer uses cream of tartar (the spice). I have no idea why or for what. He plastered over an existing house for me today. My guess is he uses a lot more retarder than accelerator since most all of the work is one coat.


I know some plaster guys who use that to slow it down. you can buy stuff that is designed to do the same thing for cheaper but its not stocked everywhere.


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## Shellbuilder (May 14, 2006)

BCConstruction said:


> I know some plaster guys who use that to slow it down. you can buy stuff that is designed to do the same thing for cheaper but its not stocked everywhere.


Retarder is stock at any big box. I do some plaster work and always have retarder with me when i do. Generally I prefer to set up the jobs, plaster weld bonding , tape, patches, floor prep. maybe some blocking in on rough places and bring my plasterer in. We went to high school together and have worked with each other for almost 30 years.


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## Shellbuilder (May 14, 2006)

BCConstruction said:


> I know some plaster guys who use that to slow it down. you can buy stuff that is designed to do the same thing for cheaper but its not stocked everywhere.


Retarder is stock at any big box. I do some plaster work and always have retarder with me when i do. Generally I prefer to set up the jobs, p;aster weld bonding , tape, patches, floor prep. maybe some blocking in on rough places and bring my plasterer in. We went to high school together and have worked with each other for almost 30 years. I'll ask him tomorrow what the cream of tartar is for. Hes told me before, I forgot what he said.


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## Jason Whipple (Dec 22, 2007)

Shellbuilder said:


> My plasterer uses cream of tartar (the spice). I have no idea why or for what. He plastered over an existing house for me today. My guess is he uses a lot more retarder than accelerator since most all of the work is one coat.


When using modern plaster veneer systems, I can't imagine why you would want it to set off any quicker than it does.


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## Shellbuilder (May 14, 2006)

Jason Whipple said:


> When using modern plaster veneer systems, I can't imagine why you would want it to set off any quicker than it does.


I can see getting the base coats to fire off so you can trowel the top coats without waiting.I've used accelerators for blocking in seams or patches.


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## CarrPainting (Jun 29, 2010)

if I remember right, this stuff is used in the treatment of water... ugh!


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## rogerhattman (Jul 6, 2008)

The chemical you are referring to is (I think) alum aka potassium aluminum hydrate. Modern accelarators are not alum usually, but instead use milder ingredients. You will probably not find alum in big box retailers or even in plaster specialty houses. Try places that carry baking supplies, as they stock alum.


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