# How long can exterior primer sit exposed?



## JPiacentino

I recently ventured into exterior painting. I just primed a section of a house about a week ago and then BAM! A week of light rain. I used high quality SW exterior primer on cedar clapboards. Do I need to reprime or should it still be good to apply topcoats? P.S. prep work is to a t. oh, latex primer btw


----------



## Schmidt & Co.

30 days is what most manufacturers recommend before needing to be re primed.


----------



## The 3rd Coat

It will be fine, but depending on top coat, you may need to sand it, cos exterior primers dry fairly shiny, and once cured, adhesion relies solely on keying as opposed to bonding as well.


----------



## daArch

Ben Moore told me 30 days a number of years ago.

If you want a real answer, call SW and ask a chemist


----------



## robladd

Though I respect the Mods and Pryor Mods here a PT. The right answer is depends on Primer, Substrate & the Biggie, Environment. 

Follow Manufactures Recommendations for Top Coats. I have worked Marine Primers that had to be finished in 2 hours or your starting over.


----------



## Epoxy Pro

We had this happen to us. As long as the primer dried before the rain a week or 2 of the primer exposed is fine. Like stated you may have to give it a light sanding before the finish goes on.


----------



## Schmidt & Co.

robladd said:


> Though I respect the Mods and Pryor Mods here a PT. The right answer is depends on Primer, Substrate & the Biggie, Environment.
> 
> Follow Manufactures Recommendations for Top Coats. I have worked Marine Primers that had to be finished in 2 hours or your starting over.


Your right Rob. My mindset is always thinking every day _architectural_ coatings. Of course every primer and environmental condition it's applied in is different. Your mileage may vary. :thumbsup:


----------



## daArch

robladd said:


> Though I respect the Mods and Pryor Mods here a PT. The right answer is depends on Primer, Substrate & the Biggie, Environment.
> 
> Follow Manufactures Recommendations for Top Coats. I have worked Marine Primers that had to be finished in 2 hours or your starting over.


Painters following Manufactures Recommendations?!?!

BLASPHEMY ! ! ! !


(J/K ! )


Thanks Rob :thumbsup:


----------



## Schmidt & Co.

daArch said:


> Painters following Manufactures Recommendations?!?!
> 
> BLASPHEMY ! ! ! !
> 
> 
> (J/K ! )
> 
> 
> Thanks Rob :thumbsup:


You mean all that writing on the can are the INSTRUCTIONS?!!!


----------



## autobear

30 days, no need to sand. 


Sent from my iPad using PaintTalk.com


----------



## Gough

For regular long-oil primers, I learned two weeks was the limit.

EDIT: MT's post (below) reminded me that the OP was using latex. I worry less about the latex primers breaking down, although 30 days does seem like a good number for them.


----------



## Monstertruck

JPiacentino said:


> I recently ventured into exterior painting. I just primed a section of a house about a week ago and then BAM! A week of light rain. I used high quality SW exterior primer on *cedar clapboards*. Do I need to reprime or should it still be good to apply topcoats? P.S. prep work is to a t. oh, *latex primer* btw


 You put latex over cedar claps?:blink:
Any tannin bleed yet?
We usually use oil on cedar.
Sometimes 2 coats.


----------



## CApainter

Since exterior oil primers will begin the oxidizing curing process almost immediately, lending itself to hardening after a time, I would think that these primers should be top coated sooner then later in order to prevent the need for sanding. Waterbornes, on the other hand, won't harden to the point of sanding requirements, but can be subject to surface contamination from the surrounding environment, as Rob suggested. Therefore, primers in general should be top coated while they are in a sterile state.


----------



## Oden

a freind of mine had someone(.and he got robbed to) prep and prime his house. Then disappear or whatever. Prolly four years or so that primer was on there. I put finish on top of it. Like I said. Prolly four or so years later. Now that finish is about four years old. Looks good still.


----------



## Paint guy 55

30 days on acrylics. 7 on alkyds.


----------



## CApainter

Oden said:


> a freind of mine had someone(.and he got robbed to) prep and prime his house. Then disappear or whatever. Prolly four years or so that primer was on there. I put finish on top of it. Like I said. Prolly four or so years later. Now that finish is about four years old. Looks good still.


I don't consider this as any example of the proper conditions required for a scientific conclusion on primers. It probably wasn't even primer, but rather BEHR's Primer/Finish. Which, in fact, may have provided the best test conditions.


----------



## Oden

CApainter said:


> I don't consider this as any example of the proper conditions required for a scientific conclusion on primers. It probably wasn't even primer, but rather BEHR's Primer/Finish. Which, in fact, may have provided the best test conditions.


Naah. It was oil. My freind, a carpenter, was very much into what material got used. He bought it too. Cedar siding.
It wasn't either that the guy he had do it did a bad job. He spent forever on it on a per day deal. Like a whole summer.
I broght in two other guys and painted it in three days. The Fourth of July we finished it on. I remember that.
Lol. I got not one, but two real good painters to come to work on the fourth.


----------



## Gymschu

Oden said:


> a freind of mine had someone(.and he got robbed to) prep and prime his house. Then disappear or whatever. Prolly four years or so that primer was on there. I put finish on top of it. Like I said. Prolly four or so years later. Now that finish is about four years old. Looks good still.


Over the years I have had several projects that started in the fall with prep and primer and then got stopped by the onset of bad/winter weather. I didn't re-prime in the spring and those jobs held up just fine. Could be just the luck of the draw but I can't imagine a couple weeks affecting topcoat adhesion at all.


----------



## JPiacentino

Monstertruck said:


> You put latex over cedar claps?:blink:
> Any tannin bleed yet?
> We usually use oil on cedar.
> Sometimes 2 coats.


slight tannin bleed before the coat was even dry. spot primed over the bleeds the next day and that seemed to resolve the issue.


----------



## JPiacentino

Monstertruck said:


> You put latex over cedar claps?:blink:
> Any tannin bleed yet?
> We usually use oil on cedar.
> Sometimes 2 coats.


 Told SW dude it was cedar and still suggested latex. Lesson learned.


----------

