# *exterior primer* for old wood/paint substrate



## sensitive skin (Jul 24, 2013)

Hi. Very old shingles and clap, lead paint, oil paint, however we have in places some acrylic topcoat from within the last 20 years that won't be coming off entirely...

There have been areas of the house that due to their exposure and their history with previous jobs, I stripped them down to 95% bare wood. I used trouble shooter linseed/alkyd...

I've moved onto areas of the house that will not be getting down to 100% bare wood, there is some relatively recent acrylic that is still solidly bonded, including small odd sections of new shingles.

My question is what kind of primer can I spray now that I'm not looking at bare wood. Areas of these sides are 75%+ bare wood and then some areas have 50%+ stable acrylic after my prep...

I don't want to spot prime the bare wood.

Looking for a reasonably sandable primer because ill be using bondo after prime.

Thinking trouble shooter acrylic. any suggestions?


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## cocomonkeynuts (Apr 14, 2017)

Bm094


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## sensitive skin (Jul 24, 2013)

@;


cocomonkeynuts said:


> Bm094


thanks but wouldn't it be risky as its going on top of some old acrylic in places?

...in other news, am considering zinsser smart prime or some alkyd acrylic primer... are the hybrids just hype?


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## cocomonkeynuts (Apr 14, 2017)

sensitive skin said:


> @;
> 
> 
> cocomonkeynuts said:
> ...


I misread the first post if your stuff is thightly adhering latex then the 046.


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## sensitive skin (Jul 24, 2013)

aaaaand i rebuilt my paint shaver pro... and started using it again today for the first time in a 3 or 4 years.

and there will be zero paint left on the wood now. maybe i'm less of a sissy about using that thing now but it makes it easy to completely strip the house... i figured it wasn't gonna be worth the hassle because the shingles aren't all in the same plane, wavy and broken and ****, however i'm able to finesse it and angle it and **** and its quite great

so

OIL PRIMER IT IS :vs_cool: (probably troubleshooter linseed acrylic unless someone can convince me to go another route!)


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## lilpaintchic (Jul 9, 2014)

For the very old shingles and clap, I'd go see a doctor. For everything else theres long dry oil.

**lololol sorry I really just couldn't help myself**

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## slinger58 (Feb 11, 2013)

lilpaintchic said:


> For the very old shingles and clap, I'd go see a doctor. For everything else theres long dry oil.
> 
> **lololol sorry I really just couldn't help myself**
> 
> Sent from my SM-G930V using Tapatalk




And you said I was awful!? 


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## Woodco (Nov 19, 2016)

Okay... Are you guys really suggesting that an oil based PRIMER might not be good over latex? Im serious here, cuz I would never in a million years think there would be anything wrong with doing the entire house with it, even over the well adhered latex.


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## sensitive skin (Jul 24, 2013)

Woodco said:


> Okay... Are you guys really suggesting that an oil based PRIMER might not be good over latex? Im serious here, cuz I would never in a million years think there would be anything wrong with doing the entire house with it, even over the well adhered latex.


Are you really asking if you can put oil between two layers of latex?? Sacrilege.

In theory however since you have stable bond between latex topcoat and oil undercoat... oil should bond to old latex. Right?

I think it's unideal. That maybe if you "scuff" the old latex with a sander, and maybe its the rare case that it sands well...

Oil primers can have a topcoat timeframe for example. You want to get your acrylic on top of your primer within 60 days, because it skins, it cures, it does stuff...

...Anyway here's what I'm looking at on my current project. It's very old siding. The existing *well bonded* acrylic that I mentioned before, that which doesn't scrape or sand right off, which represents a reasonably well done prep job in recent decades... When I take the special tool to it and actually get it off the house, (mind you this would be impossible with a sander and agonizing with a scraper or using heat), this reveals chalky ****ty old oil undercoats and mildewy wood beneath that. Hence my two ultimate reasons for taking the whole house down to bare wood, powerwashing it, and then using a long oil primer.

If I'd left that acrylic on the house before priming, and gone over it with oil or acrylic primer, it probably would have been the first spots to fail. As my new paint reached full cure it would lift the "edges" of that old **** and it would begin to fail there. I realize this is basically just an argument for taking the whole surface down to bare wood.

...Little scraps of old acrylic (as well as chalk deposits) may disturb an oil primer coat, versus acrylic primers aren't going to stick as well to bare wood, nor will the preserve the wood as well...


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## Woodco (Nov 19, 2016)

Yeah, you obviously wouldnt want sandwich oil and latex PAINTS, but primer is a different story. Its not something Ive ever actually done, on an exterior, but I've never heard anyone suggesting against it. I try to spot prime raw exterior stuff with oil. What am I gonna do? NOT get any on the latex around it? Thats unrealistic, and I seriously doubt its gonna make the paint fail, but, hey, I could be wrong.

I'd like to hear more peoples thoughts on this, actually.

I just dont think there'd be anything wrong with priming over the spots of acrylic with long oil, if you're pretty much doing the whole house with it anyway. If you're that worried about it, why not just NOT prime the acrylic spots?


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## lilpaintchic (Jul 9, 2014)

Personally, I like long dry oil on any exterior bare wood. I'd drive right over well bonded latex with it and not think twice if there was enough bare wood to justify priming it in its entirety. Otherwise spot priming in oil which usually means some of the area around it as well. If for no other reason than to deal any tannins and prevent bleeding that always seems to be problematic with wbs. To each their own I guess. Im old skool, dont like to try new things when the old stuff works just fine every time....also seems to hold up better and longer in most cases I think. 
OP, hope you're dealing with the lead appropriately. Sounds like taking it off, sanding it back to a stable surface and starting over is the long way and also the best way to achieve the desired results. A splash of thinner will aid in penetration when ya finally get to prime it.

I think its ridiculous to think having an ob primer between latex layers is a bad thing. That's just dumb.its a non issue. Think about it, we do it all day long on interiors. An exterior is no different in that regard. It has 2 main functions in either situation. Seal and/or bond. The it gets a topcoat. The top coat is where the surface protection is not the primer..the primer is just prep.


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## PACman (Oct 24, 2014)

Use the alkyd troubleshooter. Go forth and be a success my friend. Ignore the naysayers and the heretics!


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## Woodco (Nov 19, 2016)

PACman said:


> Use the alkyd troubleshooter. Go forth and be a success my friend. Ignore the naysayers and the heretics!


What does that mean? Im seriously trying to learn something here.


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## lilpaintchic (Jul 9, 2014)

Woodco said:


> What does that mean? Im seriously trying to learn something here.


I believe pac is referring to this...









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## Woodco (Nov 19, 2016)

Oh, that makes sense...


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## BeerbowerPainting (Jul 31, 2018)

My paint rep suggested a slow dry oil primer for some exterior wood and I love it. I use it on any raw wood or wood that is painted but very dry. Old T1-11 siding with a good oil prime and 2 coats of Manor Hall looks great!


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## sensitive skin (Jul 24, 2013)

lilpaintchic said:


> I believe pac is referring to this...
> 
> 
> 
> ...


This is the stuff. already have about 4 gallons on the house will be putting down another 3 or 4 soon on the side I'm working on. It sands beautifully after a week or two and i trust that it's going to be very durable and preserve these ancient shingles for at least another 50 years.

...As for the oil going over acrylic part, of course I've sprayed oil primer over patches and sections of leftover acrylic. I'm just saying its not ideal. With a lot of sanding to feather out the edges of the stuff that didn't want to come off, you end up with a patch of chalky old oil leading into the edge of the old latex, it doesn't really matter what goes first on that it's going to be where the new paint job starts to fail, at the old edges of the old paint...

Anyway my original post was just asking about an acrylic primer because, before reawakening my paint shaver pro tool, I was looking at an awful mess of mostly old latex bonded to much older oil with patches of bare wood throughout. There were areas that had so much recent acrylic on them that it would have been senseless to put an oil primer over them, or so I felt.

Bare wood its the obvious choice to go with an oil primer.

Whereas the special "bonding" primers etc that are designed for when substrate is a ****ty blend of paints and/or prep is inadequate are acrylic. e.g. SW primeRX or whatever you call it. It's a stabalizing gluey paint, and it goes on pretty thin I'd trust that stuff if i ever caught myself doing an incomplete prep job. All I'm getting at here is theres a reason why latex primers are spec'd for substrates that include a lot of existing latex... if only because its gonna make it all fail more uniformly.

aaaaanyway yeah if I'd actually had to paint over all that nasty patchy existing acrylic then I would have used troubleshooter alkyd acrylic because frankly im intrigued by alkyd acrylics and i bet its a promising tech... BM sells a product called smartprime i was also thinking of trying that. i'd have been looking for an acrylic that i could have built up and that would have sanded well


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## Brushman4 (Oct 18, 2014)

I was under the impression that linseed oil was a veritable feast for mold spores?:surprise:


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## cocomonkeynuts (Apr 14, 2017)

Brushman4 said:


> I was under the impression that linseed oil was a veritable feast for mold spores?:surprise:



Yup saw a jobsite where it looks like a mushroom farm on a guys shingles. His solution? Powerwash and apply more BLO!


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## lilpaintchic (Jul 9, 2014)

Brushman4 said:


> I was under the impression that linseed oil was a veritable feast for mold spores?:surprise:


As a finish, yes, it is. As a primer it doesn't matter....the linseed helps to penetrate and preserve, then top coat with acrylic...the feast gets buried and the spores cannot adhere and multiply on it....not like the would anyway.


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