# newly plastered



## daArch (Mar 15, 2008)

In your opinion (and experience) how long to apply latex primer/sealer after skim coating?


Thru the years I have heard from 3 to 30 days. 

Do you test for moisture ? If so how?


Do you test for pH? If so how?


Also, is BM Super Spec Undercoater and Primer Sealer #253 considered a high build/fill primer? (20% Limestone, 5% Kaolin) ?

(Trying to recommend best course of action for a job that WAS scheduled for next Tuesday that was just "plastered" )


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## daArch (Mar 15, 2008)

Seriously?

No has recommendations or protocol for priming newly plastered walls?

37 views and nothing ?


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## Gough (Nov 24, 2010)

daArch said:


> Seriously?
> 
> No has recommendations or protocol for priming newly plastered walls?
> 
> 37 views and nothing ?


<<<<crickets>>>>>


Sorry, I don't think here's been a new plaster wall is this county in 50 years.


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## Schmidt & Co. (Nov 6, 2008)

30 days cure and a quality acrylic primer.


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## Schmidt & Co. (Nov 6, 2008)

Just reread your initial post. I'd be concerned about lime burn through with a quick turnaround on the plaster. Although I don't run into fresh plaster much, I will on occasion come in after a plaster repair. I've never done any PH testing personally, so the 30 days wait time has served me well.


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## Gough (Nov 24, 2010)

Arch, I figured one of the old guys would step up to help out....


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## Smearologist (Apr 9, 2014)

Is it real lime slaked plaster over lath,or is it acrylic plaster over blue board?
Alkaline was the concern for lime slaked and that's where the ph test came in.
It was supposed to fall within the manufacturers paint specs,but I can't remember what numbers were acceptable as it's been years since I've done a real plaster job.
Dry enough to paint was when it turned a slight pinkish hue,but in all honesty it always looked white to me.
Prime was always oil and usually a 6" block brush as recently as 35 years ago,although I guess that ain't so recent.
Don't know if I've been any help at all,but thanks for the memories.:jester:


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## Susan (Nov 29, 2011)

In my opinion, no it's not high build. Tambasco told me years ago about oil priming with a 30 day out time. It's been a bit since I've read a bag of diamond or imperial, but I remember something about a 24 hour decoration time, assuming all things constant. 


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## Gough (Nov 24, 2010)

Csheils said:


> In my opinion, no it's not high build. Tambasco told me years ago about oil priming with a 30 day out time. It's been a bit since I've read a bag of diamond or imperial, but I remember something about a 24 hour decoration time, assuming all things constant.
> 
> 
> Sent from my iPhone using PaintTalk.com


Here's the "Decorating" section from USG's pages for Imperial:

It is recommended that all plaster finishes be painted (decorated) unless the finish is considered acceptable undecorated. Unsealed ImperIal veneer finish may be painted the day after application, with a breather-type paint. No matter what paint or decoration is used, it is essential that the plaster be completely dry. Typically, veneer plasters may be dry in as little as 24 hours. Use a high-quality, undiluted acrylic latex, vinyl copolymer or alkali-resistant alkyd paint. All applied finishes, such as epoxy-based finish systems, must be properly sealed before finishing. Quick-drying vinyl-acrylic latex or alkali-resistant alkyd primer-sealers are recommended. Polyvinyl acetate (PVA) -based primers should not be used. The PVA film is subject to rewetting and will almost certainly cause bond loss and subsequent paint delamination.


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## Susan (Nov 29, 2011)

Gough said:


> Here's the "Decorating" section from USG's pages for Imperial:
> 
> 
> 
> It is recommended that all plaster finishes be painted (decorated) unless the finish is considered acceptable undecorated. Unsealed ImperIal veneer finish may be painted the day after application, with a breather-type paint. No matter what paint or decoration is used, it is essential that the plaster be completely dry. Typically, veneer plasters may be dry in as little as 24 hours. Use a high-quality, undiluted acrylic latex, vinyl copolymer or alkali-resistant alkyd paint. All applied finishes, such as epoxy-based finish systems, must be properly sealed before finishing. Quick-drying vinyl-acrylic latex or alkali-resistant alkyd primer-sealers are recommended. Polyvinyl acetate (PVA) -based primers should not be used. The PVA film is subject to rewetting and will almost certainly cause bond loss and subsequent paint delamination.



So what is your verdict? 


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## Gough (Nov 24, 2010)

Csheils said:


> So what is your verdict?
> 
> 
> Sent from my iPhone using PaintTalk.com


Wait until it's dry and prime with a quality latex primer, although I think we have a few gallons of PPG #6-3 alkyd alkali-resistant primer.


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## Pete Martin the Painter (Nov 8, 2012)

daArch said:


> In your opinion (and experience) how long to apply latex primer/sealer after skim coating?
> 
> 
> Thru the years I have heard from 3 to 30 days.


I had the same question awhile back, and found the same time frame. I was going to paint for an acquaintance, but ultimately did not get the job because I was too busy--the job had turned into a nightmare and they could not use there living room or kitchen for seven months and wanted it done asap. If they had waited 30 days for the plaster to dry I could have done the job. I hope that they did not paint it too soon.


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## daArch (Mar 15, 2008)

I assume this small powder was skim over blue board, but I never got that answer.

I informed her that I had heard various times of 3, 7, and 30 days for dry and cure and that it should be tested for both moisture and pH. I also said that whoever primes it with a TOP quality 100% acrylic primer/sealer should be willing to take full responsibilities for any issues that may arise. And that I would want the primer to dry/cure for 48 hours before hanging a liner and the finish paper

She emailed back that it will be primed on Monday , and wants to know if I can shift my schedule to line and hang on Thurs - Fri. Which I can not. 

USG in the past has told me to test moisture content with a piece of plastic taped to the wall overnight. If the plastic has condensation on wall side, it ain't dry. 

I've never understood the need for speed when one or two days could be the difference between a happy ending vs years of misery.


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## Gough (Nov 24, 2010)

daArch said:


> I assume this small powder was skim over blue board, but I never got that answer.
> 
> I informed her that I had heard various times of 3, 7, and 30 days for dry and cure and that it should be tested for both moisture and pH. I also said that whoever primes it with a TOP quality 100% acrylic primer/sealer should be willing to take full responsibilities for any issues that may arise. And that I would want the primer to dry/cure for 48 hours before hanging a liner and the finish paper
> 
> ...


So, you do more than just hang paper??


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## daArch (Mar 15, 2008)

Gough said:


> So, you do more than just hang paper??


Pays the bills 

(or as Mud would say - pays Bill)


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## slinger58 (Feb 11, 2013)

Gough said:


> Arch, I figured one of the old guys would step up to help out....


If ever a post needed Lol'ing.............:yes:


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## DeanV (Apr 18, 2007)

This is what I was told:

The old guys like oil because it always ends up looking good. The problems do not show up for years as the saponification reaction takes place over hot plaster. But, the alkyd puts a nice even coat on top for now though. The failure is the same deal we see on all too many older plaster homes where the finish is flaking off shiny plaster with no dust underneath.

Acrylics, if the plaster is too hot may dry uneven or pinhole, but adhesion will still be sound. So, appearance may be affected but it may require a plaster reskim in areas, etc. Acrylics are more pH tolerant though.

Loxon by SW has the most pH tolerance of any TDS I read.

Old plaster guys that use a lime hydrated plaster skim coat will always refuse to listen to the paint manufacturer, paint reps, or painters. Every. Single. Time.


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## mudbone (Dec 26, 2011)

DeanV said:


> This is what I was told:
> 
> The old guys like oil because it always ends up looking good. The problems do not show up for years as the saponification reaction takes place over hot plaster. But, the alkyd puts a nice even coat on top for now though. The failure is the same deal we see on all too many older plaster homes where the finish is flaking off shiny plaster with no dust underneath.
> 
> ...


Deanslist!:yes:


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## NACE (May 16, 2008)

DeanV said:


> This is what I was told:
> 
> The old guys like oil because it always ends up looking good. The problems do not show up for years as the saponification reaction takes place over hot plaster. But, the alkyd puts a nice even coat on top for now though. The failure is the same deal we see on all too many older plaster homes where the finish is flaking off shiny plaster with no dust underneath.
> 
> ...


BM Fresh Start 046 will handle 13 pH. We always tested plaster with plastic before I bought a Tramex Non Contact Moisture Encounter. (Concrete moisture meter) old days we used alkyd primer sealer BM 200-00. It had a sheen to it so you could determine if the surface was uniformly sealed. Plaster can be tested with phenalthaline which turns certain shades of purple to determine if it's paintable. We use to know our plaster guys very well to insure the lime content was not too high. These days most acrylic primers are permeable and will allow moisture to evaporate but I like to see MC <4%


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## Hog (Apr 4, 2013)

I test with a moisture meter , and also a ph pencil. Minimum 7 days, and then we only use masonry primer like SW Loxon, it has a 24 hour recoat time. Then for paper I re prime with an acrylic prep coat.
I tell customers that specs dictate 30 day wait time, they need to sign off on anything primed or painted sooner, but that we have had good results waiting 7 days and using masonry primer if it test low for moisture and ph. 
I did have one job in the last few years that tested fine, but after priming and painting you could see a pattern. We let it cure longer, oil primed and re coated, lucky it wasn't too big of an area. Under wallpaper it would not have been an issue


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## dyneser (Jul 26, 2011)

4-5 days naturally on its own Bill. This time of year is perfect, no humidity & also the heat isn't cranking in the house. Super spec is fine but upgrade if they want. Ps. Plenty of sandpaper if it's any of the plasterers in Boston i've ever worked behind. Don't worry the scientific nonsence lol!


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