# Sanded (adding sand) to veneer plaster



## SteveJ (Jul 12, 2013)

Some questions for you guys. First, thank you for the forum. It's been help for some time. I've been a member for some time and used it as reference but unfortunately, never had anything of value I could add vs. some of the post already answered. Here are a few questions, I have not seen questions on or answer to.

1) USG Diamond does not specify "clean silica sand" sieve requirements.
2) USG Diamond references quantities used in "coffee cans" on spec sheets.

First: Silica sand can be purchased from essentially course ~#10 up to powder fine ~#100. Pool filter sand is ~#20 which is too course. I did find a reference that stated use "fine" silica sand, so I'm assuming that would be for say commercial grade quickrete silica fine sand is #30-#70. The coercivity can be set to taste obviously. 
Question: What do most of you seasoned guys use for sanding (adding to) veneer plaster...or do most of you guys just choose "fine" grade sand?

Second: Depending on which spec sheet you refer to from Diamond, they reference a max of 20lb to one 50lb bag or to retain hardness, no more than 12.5lbs per bag of silica sand. Surprisingly, they noted in one spec sheet P777 (not the same one noting the 12.5lb max suggestion) mixing up to the volume of one 3lb coffee can of sand to one bag mix. How the heck do you equate how much sand to use (max) if you don't have a 3lb empty can of coffee? The only conclusion I can come up with is the coffee can may suggest that is 12.5lbs from one of their other spec sheets they've created. 
Question: How much sand do you guys mix in one 50lb bag of plaster to the end results of a) sparse sand, b) med sand, c) aggressive sand in the final results or appearance?


Thanks in advance!


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## endo_alley (Nov 2, 2013)

Which begs the question - Why put silica sand in finish coat plaster?


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## SteveJ (Jul 12, 2013)

endo_alley said:


> Which begs the question - Why put silica sand in finish coat plaster?


 wow...I'm happy that endo has an comment to bring...though I wasn't asking for an opinion of why not to use it, I can appreciate the question. My discussion was to bring attention to plaster specs given by a manufacturer and what each professional uses in practical applications. 

USG did not know how to interpret their explanation/specification of usage of material. 

Diamond can be finished to many textures, smooth is just one type. Sand adds another dimension to a final finish. Myself personally when walking through a venue, viewing multiple finishes in different locations builds a characterization of each room. Sometimes, a similar finish coat that is run through an entire location even though it may be performed well, can be one note.


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## Kiwiman (Jun 14, 2008)

Not meaning to rain on your parade but for sand texture (interior) here they just put silica sand in the paint and use a wide brush to give it a trowelled cement look, only ever seen it once though.


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## SteveJ (Jul 12, 2013)

Adding sand to paint on a non sanded surface is performed in Pittsburgh as well.


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## MrWillys (Mar 10, 2014)

The MSDS says 1.5% silica.

https://www.usg.com/content/dam/USG...-diamond-veneer-finish-sds-en-53000010003.pdf


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## SteveJ (Jul 12, 2013)

MrWillys said:


> The MSDS says 1.5% silica.
> 
> https://www.usg.com/content/dam/USG...-diamond-veneer-finish-sds-en-53000010003.pdf


 I believe the safety sheet is suggesting 1.5% silica is present (composition) in the product, not the max % of silica that can be added.


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## MrWillys (Mar 10, 2014)

SteveJ said:


> I believe the safety sheet is suggesting 1.5% silica is present (composition) in the product, not the max % of silica that can be added.


 If you modify the mixture you own it and USG doesn't have to stand behind it. Must be installed as per manufacturers instructions. I would never ask my people to do it any other way.


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## endo_alley (Nov 2, 2013)

In an odd sort of coincidence, since my asking why use sand in plaster; we were asked to do a sand finish texture in an apartment. We decided to use all purpose compound and sand, instead of plaster.


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## endo_alley (Nov 2, 2013)

photos


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## SteveJ (Jul 12, 2013)

MrWillys said:


> If you modify the mixture you own it and USG doesn't have to stand behind it. Must be installed as per manufacturers instructions. I would never ask my people to do it any other way.


 Actually, they do give specific (well sort of) directions with regards to adding sand within their P777 submittal sheet specifically stating: 

"Note: If sand is desired, add up to one volume (a measured 3 lb. coffee can or equivalent) of ﬁne silica sand meeting ASTM C35 to each batch using either DIAMOND Interior Finish or IMPERIAL Finish Plaster. Sand should be added when plaster has nearly reached proper consistency. This quantity of sand will not change the ﬂuidity of the mixture" 

This is what brought of my initial discussion. I spoke with a few Engineers at USG as for them to give an explanation of either the weighted or volume of this reference in actual STANDARD units...lol not using a coffee can as a standard unit of measure. They do offer a sanded version as well fwiw. I'm surprised that many think this is odd as to using sand in mixes. Even something as simple as matching a typical Kal kote sanded mix or old fashion mixes with sand. lol endo...


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## SteveJ (Jul 12, 2013)

btw endo, that looks like you used standard dark unwashed sand. Commercial grade fine silica sand is what I use fwiw. It leaves a completely different finish. I personally don't use that much sand in a mix either. Typically 2 cups max per 50lb bag. Going too high makes the wall very course and the sand is sharp so if you bump against the wall, you'll be loosing skin. lol.


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## MrWillys (Mar 10, 2014)

SteveJ said:


> Actually, they do give specific (well sort of) directions with regards to adding sand within their P777 submittal sheet specifically stating:
> 
> "Note: If sand is desired, add up to one volume (a measured 3 lb. coffee can or equivalent) of ﬁne silica sand meeting ASTM C35 to each batch using either DIAMOND Interior Finish or IMPERIAL Finish Plaster. Sand should be added when plaster has nearly reached proper consistency. This quantity of sand will not change the ﬂuidity of the mixture"
> 
> This is what brought of my initial discussion. I spoke with a few Engineers at USG as for them to give an explanation of either the weighted or volume of this reference in actual STANDARD units...lol not using a coffee can as a standard unit of measure. They do offer a sanded version as well fwiw. I'm surprised that many think this is odd as to using sand in mixes. Even something as simple as matching a typical Kal kote sanded mix or old fashion mixes with sand. lol endo...


 Clearly, I did not realize the depth of your question. Maybe your answer can be found in ASTM 35?


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## endo_alley (Nov 2, 2013)

SteveJ said:


> btw endo, that looks like you used standard dark unwashed sand. Commercial grade fine silica sand is what I use fwiw. It leaves a completely different finish. I personally don't use that much sand in a mix either. Typically 2 cups max per 50lb bag. Going too high makes the wall very course and the sand is sharp so if you bump against the wall, you'll be loosing skin. lol.


We used one quart of medium silicate sand and one quart of washed all purpose sand which was run through a coarse colander per box of all purpose. The finish we were after was much like a stucco exposed aggregate finish. Basically a fairly smooth background with the sand exposed. No skip pattern or surface voids of any kind. Fine sand would not produce this finish. I tried to convince the builder to let us color the mud, followed by a poly sealer. This would have given the walls a speckled color finish. But they didn't go for that.


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## SteveJ (Jul 12, 2013)

MrWillys said:


> Clearly, I did not realize the depth of your question. Maybe your answer can be found in ASTM 35?


 Yea, that material I mentioned does meet this specification the ASTM refers to material structure, not quantity. I know these are weird questions/comments but it's just things I look at...it was especially odd to reference quantities in non-standard units (lol a 3lb coffee can being specifically referenced...really). I think I mentioned this previously but if not, when I discussed this with USG engineers, they were stumped as well and never had a person ask what the maximum allowable volume or mass was...only it was referenced to a 3lb coffee can! ...and give a damn suggested sieve number instead of having to jump through hoops to figure out mfg suggested specs...lol.

I made a joke of the coffee can reference and mentioned that my wife had a great cookie recipe. 3eggs, 2 Reebok shoe fulls of flour and 2 rounded baseball hats full of sugar. ...something like that

endo...whatever the customer want right . shame on you that you didn't have a coffee can to measure these amounts huh


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## Mr.Brightstar (Dec 2, 2011)

I can remember using diamond Imperial right on top of cinderblock sand swirl finish with sponge. Fish-scale pattern. 1 coat chit.


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## endo_alley (Nov 2, 2013)

The client we worked for recently did not want any skip trowel, swirls, holiday type openings, etc. or any such busy patterns in the finish. As smooth as we could get the background but with exposed aggregate evenly spaced in the foreground of the texture. Heavy textures, swirls and the like, are not very popular around here. And any kind of spray on texture or knockdown went out of style decades ago.


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## Mr.Brightstar (Dec 2, 2011)

endo_alley said:


> The client we worked for recently did not want any skip trowel, swirls, holiday type openings, etc. or any such busy patterns in the finish. As smooth as we could get the background but with exposed aggregate evenly spaced in the foreground of the texture. Heavy textures, swirls and the like, are not very popular around here. And any kind of spray on texture or knockdown went out of style decades ago.



Look into sto or drivit sand finishes. You can use it on drywall, prime drywall first.


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## endo_alley (Nov 2, 2013)

Mr.Brightstar said:


> Look into sto or drivit sand finishes. You can use it on drywall, prime drywall first.


We do that kind of exterior sand finish quite a bit. Often with a Portland mix that gets treated with a sponge float. A synthetic finish that is floated with a plastic trowel makes a nice exposed aggregate finish also, although a bit heavier in consistency. But I don't see how that would have been an improvement on the interiors we did using AP compound and sand, likewise washed with a sponge.


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## Mr.Brightstar (Dec 2, 2011)

It's a different texture no doubt. More cost effective to add sand to all purpose.


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## lrees (Jan 22, 2013)

We're use 6 coffee cans per full 5 gal bucket of finish for sand finish.... Other finishes like Spanish and orange peel etc we use around 3 cans... (For a 5 gal bucket). At the end it looks nice! Everything is fine sand that is used...


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## SteveJ (Jul 12, 2013)

lrees said:


> We're use 6 coffee cans per full 5 gal bucket of finish for sand finish.... Other finishes like Spanish and orange peel etc we use around 3 cans... (For a 5 gal bucket). At the end it looks nice! Everything is fine sand that is used...


 Thanks for that feedback. Do you really measure using a coffee can? Problem is I always use coffee beans which do not come in a dam can! What size can do you use? Diamond recommends no more than a 3lb can of fine silica sand per 50lbs (which is essentially one 5 gallon bucket). that's if you want to keep the PSI strength of the plaster.


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## endo_alley (Nov 2, 2013)

I am going to take this post way out in left field now. I met someone years back who put coffee grounds in his plaster / texture coat. He would then leave the texture unpainted and merely seal it with poly. Apparently the coffee grounds would leach brown streaks through the texture and give the finished wall an interesting effect. I never saw the finished product.


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## SteveJ (Jul 12, 2013)

endo_alley said:


> I am going to take this post way out in left field now. I met someone years back who put coffee grounds in his plaster / texture coat. He would then leave the texture unpainted and merely seal it with poly. Apparently the coffee grounds would leach brown streaks through the texture and give the finished wall an interesting effect. I never saw the finished product.


 lol I wonder if it was initially by mistake by using an old coffee can not cleaned out from old coffee...


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## endo_alley (Nov 2, 2013)

My guess is that the guy stumbled upon this idea after mixing Texas medicine with railroad gin.


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## TomRestore (Oct 29, 2017)

MrWillys said:


> If you modify the mixture you own it and USG doesn't have to stand behind it. Must be installed as per manufacturers instructions. I would never ask my people to do it any other way.


strongly agreed with you!!!:thumbsup:


"Username" T. - Always Preferred
www.wedefineclean.net


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