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Discussion Starter · #22 ·
They have plenty of topcoats available that have superior 'grip.' in a nutshell, most anything urethane modified will stick like crazy, not that many products are gonna have an issue sticking to exterior stained wood. It has 'teeth.'

That said, I dont know why youre worried about peeling. You said yourself, it doesnt see any elements. What exaclty is gonna break down the new topcoat when the previous topcoat lasted 25 years? Paint doesnt just peel for no reason.
Thats what i was wondereing. But searching polyurethane top coating keeps getting me floor coatings. And 'grip' marketing seems to only come up with primer.
It occurs to me Maybe i should try "polyurethane modified" as a string, but what names are associated with these products? If i have a manufacturer and line maybe i can just find these without generic searching. Thanks
 

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I work on buildings, interior and exterior, all day every day. Maybe 20% of that is painting.
Just an FYI - if indeed you are switching from Solid Stain to a Prime+Paint approach, you are setting the homeowner up for a Scrape+Prime+Paint about 10 years from now.

In my experience, the homeowner is never happy about this when that time rolls around, and painters never rush to bid on scrape jobs. Perhaps it doesn't matter in the end, but it might be worth considering the ramifications of long-term maintenance when making major product changes, and at the very least let the homeowner know what you are doing.

Prime+Paint is the classic approach for Pine Siding, and Solid Stain is typical for Cedar.
 

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Thats what i was wondereing. But searching polyurethane top coating keeps getting me floor coatings. And 'grip' marketing seems to only come up with primer.
It occurs to me Maybe i should try "polyurethane modified" as a string, but what names are associated with these products? If i have a manufacturer and line maybe i can just find these without generic searching. Thanks
Not polyurethane, 'urethane modified'. Polyurethane generally means clear coats. Cabinet coat, Emerald Urethane, Kelly Moore Durapoxy High Performance, Im not sure of Command, from ben Moore, but maybe. Sherwin Pro Industrial urethane alkyd. (this might be good, because it is interior/exterior, while some of those products are only interior rated. Pro Industrial™ Urethane Alkyd Enamel - Sherwin-Williams

And no, its not at risk of any kind of scrape and prime, because its practically an interior surface. I dont see why it would be anyway... Nothing ive ever painted has had to be scraped, down the road aside from fascia and pure wood outside trim boards, but thats gonna happen no matter what you use. And when it does happen, its going all the way to bare wood, not peeling off of a previous paint coat.

From the way you describe this, you could use interior paint on it if you really wanted to. Personally, i would just put one refresher coat of the closest product you can find to what was put there 25 years ago.
 

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Good rule of thumb that has always served me well is to thoroughly read the spec sheet on any given product and then use and apply it according to what is recommended.
 

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For an argument not to, what I'm personally a bit unsure of is what is going on with "urethane modified" waterbased paints. I'm not sure what it actually means chemically, as in, what kind of resin is being added, etc, to make that happen and make it substantially different than other latex paints. As in, the now deceased (my favorite paint of all time) Muralo Ultra never advertised itself as "urethane modified" but in practical application felt, looked, and acted like newer "urethane modified" paints like Sherwin Williams Emerald Urethane, or Behr's knockoff of it, etc, despite being around since the 90s. It was distinctly better than a WB Alkyd like Advance, imo. I think for semantics nothing that is not two component is a true "urethane" anyway, even "Spar Urethane" is technically just an alkyd varnish. I might be wrong, but I think the only "true" urethanes are industrial or automotive, or the fancy European cabinet coatings that are 2K or two component, and even those I'm not that familiar with enough and could even be wrong about the specifics of those.

That said, the "urethane modified" paints and primers do seem to act better and are more durable than their older alkyd modified counterparts to some degree, but I think soon "urethane modified" will end up being the new "paint and primer in one" for marketing terms. I could be wrong, and if anyone knows more, correct me. For marketing though, PPG's Flood Solid Stain is/was "urethane fortified." That's a "urethane" solid stain. Also, even the fairly lowly/cheap Valspar "Porch and Floor" paint at Lowes is supposedly urethane fortified or modified, there's a bunch of stuff out there that has that labeling, but there's no industry unified standard for what that even means. If it's a specific resin, how much is it, 5%, 1%, .001%?

Another thing that makes me skeptical of anything urethane in exterior settings that many of the supposed urethane modified products in their data sheets say to use them only for exterior trim, not whole house work. SW Emerald Urethane specifically says that. Same with BM Command, one of the newest "urethane" paints, it specifically says not to use as a whole house paint on wood. Both dry really hard and nice like an oil, and bond well, but they're not flexible enough to handle very serious movement and expansion and contraction, so even the best bonding paint would still alligator/crack/etc, which ideally the "urethane" modified paints are supposed to be a better compromise than an oil based paint, but I'm not really sure how it is in real life, since they've not been around for 25 years. So I don't know what exact primer you're referring to, but I think it's a similar situation.

If it's a paying customer, imo, you should save science experiments for your own house or friends/family that let you experiment. It's not about whether you think it might be a great idea or not, you should try to work within the approvals/ratings of the coating company's system. To use a car analogy, if you buy a new car rated for API SP 0w20 Dexos oil, and use an API SN 15w40 diesel oil in it, because 15w40 has more zinc and it's a "stronger" oil, if the engine fails, it doesn't matter about your theory, what matters is that the proper approved API SP oil was in the crankcase when it gets back to the manufacturer so they don't deny a warranty claim. Of course there is space for anecdote/hillbilly science and forum solution type stuff, and to use a motor oil example some European cars change specs after problems come up with a factory spec over a number of years, and will use say, 0w40, in an engine spec'd for 10w60, but that's after years of the original recommendation failing. Same if you want to use 15w40 in your 90s Civic with 250K miles, knock yourself out. In your case you have a successful coating that held up over 25 years, so imo there's nothing broke to fix in that scenario.
 

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Not polyurethane, 'urethane modified'. Polyurethane generally means clear coats. Cabinet coat, Emerald Urethane, Kelly Moore Durapoxy High Performance, Im not sure of Command, from ben Moore, but maybe. Sherwin Pro Industrial urethane alkyd. (this might be good, because it is interior/exterior, while some of those products are only interior rated. Pro Industrial™ Urethane Alkyd Enamel - Sherwin-Williams

And no, its not at risk of any kind of scrape and prime, because its practically an interior surface. I dont see why it would be anyway... Nothing ive ever painted has had to be scraped, down the road aside from fascia and pure wood outside trim boards, but thats gonna happen no matter what you use. And when it does happen, its going all the way to bare wood, not peeling off of a previous paint coat.

From the way you describe this, you could use interior paint on it if you really wanted to. Personally, i would just put one refresher coat of the closest product you can find to what was put there 25 years ago.
The picture provided by OP is exterior, but found his post and questions confusing, so it could be he is painting interior.
 

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Celicaxx - I’m thinking that the OP could have done the job, and in the manner you suggest, in less time then it took you to write that response.
Well, I want my question answered on what exactly is in these "urethane modified" and "urethane fortified" latex paints, for one thing. To me it frankly seems like marketing. Or what, can I just dump some Minwax Polycrylic into some paint and call it "urethane fortified" too?
 

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Well, I want my question answered on what exactly is in these "urethane modified" and "urethane fortified" latex paints, for one thing. To me it frankly seems like marketing. Or what, can I just dump some Minwax Polycrylic into some paint and call it "urethane fortified" too?
Disclaimer: I’m not an expert, but this may help.

As you know, all paints are composed of three things:
1. Pigment
2. Binder (resin)
3. Solvent (liquid).
*additives and extenders can be added to improve special characteristics.

when the solvent (in wb paints the solvent is water) dries, the pigment and binder (resin) are left behind and become one. Binder is responsible for adhesion, durability, gloss (eg., semi gloss paints have more binder) etc… In urethane fortified paints, the Binder has urethane (a plastic that I believe is a polyurethane ?). Less expensive urethane paints can have as little as 10%, mixed with Acrylic for example.

it’s not marketing, it is chemistry. Urethane paints are durable, and stick to surfaces well. Different combinations can be utilized for different needs. Incidentally, The low-quantity urethane fortified formulations are the only ones that are safe to use without respirators.
 

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For an argument not to, what I'm personally a bit unsure of is what is going on with "urethane modified" waterbased paints. I'm not sure what it actually means chemically, as in, what kind of resin is being added, etc, to make that happen and make it substantially different than other latex paints. As in, the now deceased (my favorite paint of all time) Muralo Ultra never advertised itself as "urethane modified" but in practical application felt, looked, and acted like newer "urethane modified" paints like Sherwin Williams Emerald Urethane, or Behr's knockoff of it, etc, despite being around since the 90s. It was distinctly better than a WB Alkyd like Advance, imo. I think for semantics nothing that is not two component is a true "urethane" anyway, even "Spar Urethane" is technically just an alkyd varnish. I might be wrong, but I think the only "true" urethanes are industrial or automotive, or the fancy European cabinet coatings that are 2K or two component, and even those I'm not that familiar with enough and could even be wrong about the specifics of those.

That said, the "urethane modified" paints and primers do seem to act better and are more durable than their older alkyd modified counterparts to some degree, but I think soon "urethane modified" will end up being the new "paint and primer in one" for marketing terms. I could be wrong, and if anyone knows more, correct me. For marketing though, PPG's Flood Solid Stain is/was "urethane fortified." That's a "urethane" solid stain. Also, even the fairly lowly/cheap Valspar "Porch and Floor" paint at Lowes is supposedly urethane fortified or modified, there's a bunch of stuff out there that has that labeling, but there's no industry unified standard for what that even means. If it's a specific resin, how much is it, 5%, 1%, .001%?

Another thing that makes me skeptical of anything urethane in exterior settings that many of the supposed urethane modified products in their data sheets say to use them only for exterior trim, not whole house work. SW Emerald Urethane specifically says that. Same with BM Command, one of the newest "urethane" paints, it specifically says not to use as a whole house paint on wood. Both dry really hard and nice like an oil, and bond well, but they're not flexible enough to handle very serious movement and expansion and contraction, so even the best bonding paint would still alligator/crack/etc, which ideally the "urethane" modified paints are supposed to be a better compromise than an oil based paint, but I'm not really sure how it is in real life, since they've not been around for 25 years. So I don't know what exact primer you're referring to, but I think it's a similar situation.

If it's a paying customer, imo, you should save science experiments for your own house or friends/family that let you experiment. It's not about whether you think it might be a great idea or not, you should try to work within the approvals/ratings of the coating company's system. To use a car analogy, if you buy a new car rated for API SP 0w20 Dexos oil, and use an API SN 15w40 diesel oil in it, because 15w40 has more zinc and it's a "stronger" oil, if the engine fails, it doesn't matter about your theory, what matters is that the proper approved API SP oil was in the crankcase when it gets back to the manufacturer so they don't deny a warranty claim. Of course there is space for anecdote/hillbilly science and forum solution type stuff, and to use a motor oil example some European cars change specs after problems come up with a factory spec over a number of years, and will use say, 0w40, in an engine spec'd for 10w60, but that's after years of the original recommendation failing. Same if you want to use 15w40 in your 90s Civic with 250K miles, knock yourself out. In your case you have a successful coating that held up over 25 years, so imo there's nothing broke to fix in that scenario.
Ask your rep for the sell demo of command. It's painted on a piece of vinyl to show it's flexibility.
 

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Disclaimer: I’m not an expert, but this may help.

As you know, all paints are composed of three things:
1. Pigment
2. Binder (resin)
3. Solvent (liquid).
*additives and extenders can be added to improve special characteristics.

when the solvent (in wb paints the solvent is water) dries, the pigment and binder (resin) are left behind and become one. Binder is responsible for adhesion, durability, gloss (eg., semi gloss paints have more binder) etc… In urethane fortified paints, the Binder has urethane (a plastic that I believe is a polyurethane ?). Less expensive urethane paints can have as little as 10%, mixed with Acrylic for example.

it’s not marketing, it is chemistry. Urethane paints are durable, and stick to surfaces well. Different combinations can be utilized for different needs. Incidentally, The low-quantity urethane fortified formulations are the only ones that are safe to use without respirators.
I still think a lot could be marketing, though. I noticed the very cheap Valspar 2000 had "100% Acrylic" written on the back, but the data sheet says "vinyl copolymer" for its resin type. My point is I think similar marketing language is being used with these supposed "urethane fortified" and "urethane modified" paints as far as the actual composition of them.
 

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Discussion Starter · #33 ·
@Woodco my bad in referring to urethane modified as polyurethane. that also explains why my search results haven't been getting me the range of products available. whether there is or isn't chemical basis for that, I see i went off the industry script.

@celicaxx I've got an 89 and 95 convertible but thanks for being willing to drive down the rabbit hole with me.

now that i know what to search for i'm getting better industry based arguments for and against rethane modified products in various circumstances.

the thing I'm coming to like about solid color stain is that it has low film thickness. and lower film thickness is also a weapon against peelling as long as you get decent adhesion. that distinguishes stain as well as the penetrating quality (in that it has more solvent to pigment/binder) it exhibits over new work as it was used here 25 years ago.

that said, in theory you could still get better adhesion if your stains was urethane modified but that might challenge whether you can get the flat quality of solid color stain which has virtually no sheen in all applications I've seen or at least tends to that absolutely flat end of the spectrum–although i'm stretching my mind to remember if the previous coating depicted might have been oil based solid color stain because it chalks and supposedly latex solid stains don't.

finally @cocomonkeynuts I couldn't find the ben moore demo on command used on vinyl siding but I would think that is just the kind of a job where you want incredibly strong adhesion and they seem to be demonstrating (i've got a call in to our rep) that it can handle the flexing of vinyl and, i presume, the thermal expansion which is notable. So the balance of binder or the particular urethane chemistry appears focused on flexibility as well as adhesion. Of course wood can be more challenged by moisture expansion than thermal, but if there are moisture problems with notable humidity getting through to the wood material, then virtually anything is going to peel and that hasn't happened on this job so I feel safe treating it as not subject to excessive moisture content change.

thanks all for your indulging this thread and always open to any additional ideas.

brian
 

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@Woodco my bad in referring to urethane modified as polyurethane. that also explains why my search results haven't been getting me the range of products available. whether there is or isn't chemical basis for that, I see i went off the industry script.

@celicaxx I've got an 89 and 95 convertible but thanks for being willing to drive down the rabbit hole with me.

now that i know what to search for i'm getting better industry based arguments for and against rethane modified products in various circumstances.

the thing I'm coming to like about solid color stain is that it has low film thickness. and lower film thickness is also a weapon against peelling as long as you get decent adhesion. that distinguishes stain as well as the penetrating quality (in that it has more solvent to pigment/binder) it exhibits over new work as it was used here 25 years ago.

that said, in theory you could still get better adhesion if your stains was urethane modified but that might challenge whether you can get the flat quality of solid color stain which has virtually no sheen in all applications I've seen or at least tends to that absolutely flat end of the spectrum–although i'm stretching my mind to remember if the previous coating depicted might have been oil based solid color stain because it chalks and supposedly latex solid stains don't.

finally @cocomonkeynuts I couldn't find the ben moore demo on command used on vinyl siding but I would think that is just the kind of a job where you want incredibly strong adhesion and they seem to be demonstrating (i've got a call in to our rep) that it can handle the flexing of vinyl and, i presume, the thermal expansion which is notable. So the balance of binder or the particular urethane chemistry appears focused on flexibility as well as adhesion. Of course wood can be more challenged by moisture expansion than thermal, but if there are moisture problems with notable humidity getting through to the wood material, then virtually anything is going to peel and that hasn't happened on this job so I feel safe treating it as not subject to excessive moisture content change.

thanks all for your indulging this thread and always open to any additional ideas.

brian
its not on vinyl siding, its literally painted on a piece of flexible vinyl fabric that you can roll, fold, pull, flex. 1K urethanes do not have problems with movement
 

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is that a reference to particular style of urethane, or concentation or . . . .?
1K is air dry/single component urethane, 2K is 2 part urethane which is chemical set/cure with a reducer/hardener/accelerator and the base.

Also if you wanted a more glossy finish, that was imo where I liked the old PPG Flood Solid Stain, it was more like an eggshell/satin finish, I'm using it and some SW Woodscapes now and don't like the flatter finish of Woodscapes compared to Flood. I feel more comfortable with the idea of some sheen on exterior surfaces compared to flat paints, as flats will allow more water penetration/etc, but also breathe a little better, etc. I think the Flood Solid Stain is discontinued now, though. Woodscapes still has some sheen but I like Flood's look better. Perhaps some of the PPG Solid Stains being sold at HD/etc under the Olympic label are the same formula as Flood under different labels now, who knows.

Probably what I'd use now if I wanted to keep things simple and price was no object is BM Arborcoat latex solid stain in matte, but not flat, for your situation.
 

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Discussion Starter · #37 ·
Probably what I'd use now if I wanted to keep things simple and price was no object is BM Arborcoat latex solid stain in matte, but not flat, for your situation.
interestingly, command and arborcoat have the same recommended film thickness for wet application and dry result.

the only other property it occurs to me to look into which i can find on data sheets is permeability. while the exterior surface has limited penetration of exterior moisture and the space enclosed is not a bathroom or kitchen or subject to high interior moisture, the ability of the clapboard system to breath between their overlapped joints will be more reduced with additonal coats.

and, as you pointed out, the data sheets for command don't recommend for exterior house bodies and moore rep doubles down on that point. sherwin williams lists their analogous urethane offerings, e.g. emerald, as breathable interior/exterior but it is deliberately targeted at trim which seems to be a similar recommendation. i'm a little mystified why these urethane paints would be OK on wood trim but not wood body. maybe complete coverage over a broad installation makes moisture permeability is too much of an issue, and then, even with trim there is the question of caulking the clapboard ends or whether the trim is coated and moves independently and has good flashing. Moore says the contraindication of urethane paint for house body is because the paint cures harder and less flexible (mildly contradicting their demonstrating of painting sheets of vinyl you mentioned; but, again, maybe that isn't really aimed at exterior demonstration where expansion and contraction for vinyl is high). Maybe it is also less permeable but there are no specs for this. In any event, moore rep insists that arborcoat is very good adhesion so I think you have called it. I've talked myself around to the point of view of the group here. I might, just for a laugh, run one short return with satin command just to see if i can tell the difference in 5 or 8 years but i'm thinking arbor coat for the job.
 

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interestingly, command and arborcoat have the same recommended film thickness for wet application and dry result.

the only other property it occurs to me to look into which i can find on data sheets is permeability. while the exterior surface has limited penetration of exterior moisture and the space enclosed is not a bathroom or kitchen or subject to high interior moisture, the ability of the clapboard system to breath between their overlapped joints will be more reduced with additonal coats.

and, as you pointed out, the data sheets for command don't recommend for exterior house bodies and moore rep doubles down on that point. sherwin williams lists their analogous urethane offerings, e.g. emerald, as breathable interior/exterior but it is deliberately targeted at trim which seems to be a similar recommendation. i'm a little mystified why these urethane paints would be OK on wood trim but not wood body. maybe complete coverage over a broad installation makes moisture permeability is too much of an issue, and then, even with trim there is the question of caulking the clapboard ends or whether the trim is coated and moves independently and has good flashing. Moore says the contraindication of urethane paint for house body is because the paint cures harder and less flexible (mildly contradicting their demonstrating of painting sheets of vinyl you mentioned; but, again, maybe that isn't really aimed at exterior demonstration where expansion and contraction for vinyl is high). Maybe it is also less permeable but there are no specs for this. In any event, moore rep insists that arborcoat is very good adhesion so I think you have called it. I've talked myself around to the point of view of the group here. I might, just for a laugh, run one short return with satin command just to see if i can tell the difference in 5 or 8 years but i'm thinking arbor coat for the job.
I mean, with the fabric/vinyl test, I've used regular old Rustoleum spray paint on vinyl car interior parts, and even a bench press bench's vinyl covering, and flexibility wasn't an issue there. No cracking or chipping, just looooooooooooooooooong cure times of over 2 weeks. Basically I think any test like that depends on a lot of factors, that piece of vinyl while being nifty is not a wooden house exterior in weather. I don't think you'd want to be using Rustoleum spray paint on wooden siding.
 
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