# Durability of 1 vs 2 coats on exterior



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

Greetings,
I am bidding a job that is in such good shape that I know that I could cover in 1 coat...also using the same colors. However this is an exterior and I am wondering if 2 coats will be more durable than 1. 

Thanks.

Sent from my SM-A600U using Tapatalk


----------



## PACman (Oct 24, 2014)

yes it would be. Most warranties are based on a two topcoat system. For what they're worth anyway.


----------



## APPNW (Jul 9, 2019)

This ties right in with beating out the illegals. Your selling a lexus with 2 shiny coats of finish, they have the used corrola with 1 coat of cheap paint on it.

Maybe noone will know, maybe thats all it needs, maybe with your one coat the mil spec is enough to stand up to warranty specs...
Those are chances you need to decide if their worth it for you. This day and age you might just be on camera, and you can bet your work is talked about on social media. If your not doing things better than the competition people will find out.


----------



## Woodco (Nov 19, 2016)

If Im spraying, I usually just do one coat, and put it on good. I know "technically" two lighter coats are better than one heavier one, yet I've never seen an actual test of it. My philosophy is its the trim that starts to flake and peel first anyway, and that is always two coated, cuz its done by hand.

Let me add that Im always honest with my clients about it. I tell I spray two coats worth of paint in a double and its gonna last over ten years. If they want two honest coats, I tell them how much more its gonna cost.


----------



## RH (Sep 7, 2010)

Here we go again...


----------



## PACman (Oct 24, 2014)

someone popcorn me.....


----------



## PACman (Oct 24, 2014)

the paint manufacturers will always require two coats for warranty coverage, except for certain products that require a certain dry mil thickness from one coat. (duration, timeless, etc.) Of course those two coats should be of the appropriate thickness as highlighted in their respective data sheets. (I know. I'm laughing inside at this as much as you all are! I almost couldn't even type it with a straight face. But this is what they will tell you if you push them. Or have even the slightest paint failure!)


----------



## Rbriggs82 (Jul 9, 2012)

PACman said:


> someone popcorn me.....




Sent from my Pixel 2 XL using Tapatalk


----------



## Lightningboy65 (Mar 12, 2018)

APPNW said:


> This ties right in with beating out the illegals. Your selling a lexus with 2 shiny coats of finish, they have the used corrola with 1 coat of cheap paint on it.


The problem is the illegals who give 2 shiny coats of finish plus a hand rubbed 3 coat wax job, and are still at half the price as above board companies! Not all illegals do crappy work, I've seen some pretty good work by guys I'm pretty sure had no legal standing in this country. But the fact they are not paying taxes and insurance makes it hard to compete with them. It won't stop until those hiring them refuse to do so...which will be never.:sad:


----------



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

APPNW said:


> This ties right in with beating out the illegals. Your selling a lexus with 2 shiny coats of finish, they have the used corrola with 1 coat of cheap paint on it.
> 
> Maybe noone will know, maybe thats all it needs, maybe with your one coat the mil spec is enough to stand up to warranty specs...
> Those are chances you need to decide if their worth it for you. This day and age you might just be on camera, and you can bet your work is talked about on social media. If your not doing things better than the competition people will find out.


To be clear. I am not trying to sell a lemon to the home owner and claiming that it is a Lexus. I was just inquiring if 2 is better than 1 when it comes to durability. 
I actually sent her the estimate today with a 1 coat and 2 coat option. The stain that is on the house looks great. I know that it would look good with one coat, but I wanted to make sure this would last as long as the standard 2 coats. I told her that the 2 coat option would be more durable and last longer.


Sent from my SM-A600U using Tapatalk


----------



## Woodco (Nov 19, 2016)

PACman said:


> the paint manufacturers will always require two coats for warranty coverage, except for certain products that require a certain dry mil thickness from one coat. (duration, timeless, etc.) Of course those two coats should be of the appropriate thickness as highlighted in their respective data sheets. (I know. I'm laughing inside at this as much as you all are! I almost couldn't even type it with a straight face. But this is what they will tell you if you push them. Or have even the slightest paint failure!)


Is there test data comparing longevity of exterior wood two 3 mil coats dried between compared to a board with a single 6 mil wet coat? I've asked this a few times, and never got an answer...


----------



## Fman (Aug 20, 2011)

Lightningboy65 said:


> The problem is the illegals who give 2 shiny coats of finish plus a hand rubbed 3 coat wax job, and are still at half the price as above board companies! Not all illegals do crappy work, I've seen some pretty good work by guys I'm pretty sure had no legal standing in this country. But the fact they are not paying taxes and insurance makes it hard to compete with them. It won't stop until those hiring them refuse to do so...which will be never.:sad:


I've never heard of anyone selling their services by saying that they use "cheap, illegal help- AND PASS THE SAVINGS ON TO YOU!" That's just not gonna happen, I think. I think in most cases they are charging as much or more than the next guy and the one thing that might set them apart is that they might do a job faster (with more workers).


----------



## Lightningboy65 (Mar 12, 2018)

Woodco said:


> Is there test data comparing longevity of exterior wood two 3 mil coats dried between compared to a board with a single 6 mil wet coat? I've asked this a few times, and never got an answer...


Your question piqued my interest, and I spent a while searching online and could find nothing of the sorts. I couldn't even find anything on just plain old one coat vs. two. There must be something on the subject buried deep in the innerwebs, but I couldn't find it.:sad:

Common sense and experience leaves me no doubt a two coat job will significantly outlast a one coat job, but I have no empirical data to back that up. I know two coats will always look better.


----------



## jr.sr. painting (Dec 6, 2013)

Just finished up at a side job after work and the siding is all the old style asbestos. It was a color change. Using regal select low lusture. Looked great after one coat but we did a 2nd bc I have always done a second coat and it is peace of mind that you did the job to meet a spec. Just do your 2nd and be done with it. Even if you have a few missed spots or sheen inconsistency it wasn't worth quoting them 1 coat and then using your time and not getting paid to fix it.


Sent from my iPhone using Tapatalk


----------



## Lightningboy65 (Mar 12, 2018)

Fman said:


> I've never heard of anyone selling their services by saying that they use "cheap, illegal help- AND PASS THE SAVINGS ON TO YOU!" That's just not gonna happen, I think. I think in most cases they are charging as much or more than the next guy and the one thing that might set them apart is that they might do a job faster (with more workers).


I would say in many cases you're spot on. But there are many instances where the illegals work significantly cheaper. Especially when they are the contractor, not just the labor. Point in case is the guy in CO that paints for my sister and her friends. The guy has been in their area for years, him and two other illegals, does excellent work (in million $+ homes), and charges about half price. Plenty like him around the country.


----------



## Lightningboy65 (Mar 12, 2018)

jr.sr. painting said:


> Just finished up at a side job after work and the siding is all the old style asbestos. It was a color change. Using regal select low lusture. Looked great after one coat but we did a 2nd bc I have always done a second coat and it is peace of mind that you did the job to meet a spec. Just do your 2nd and be done with it. Even if you have a few missed spots or sheen inconsistency it wasn't worth quoting them 1 coat and then using your time and not getting paid to fix it.
> 
> 
> Sent from my iPhone using Tapatalk


Always two coat the old asbestos. I've seen it look great with one coat and then quickly fade out within a year if you don't second coat.


----------



## Gymschu (Mar 11, 2011)

I'm not saying this matches up with any kind of paint science, but, after painting for lo these many years and keeping track of paint/stain jobs I've done, well, I think you get an extra two years of service adding that 2nd coat. The mils, the evening out of the sheen, etc. simply gives an extra 2 years before a re-do. Is that worth it to you? Is it worth it to the customer? Hard to say for sure based on the extra cost that is added to do that second coat......just one painter's "feel" about it.


----------



## Fman (Aug 20, 2011)

Lightningboy65 said:


> I would say in many cases you're spot on. But there are many instances where the illegals work significantly cheaper. Especially when they are the contractor, not just the labor. Point in case is the guy in CO that paints for my sister and her friends. The guy has been in their area for years, him and two other illegals, does excellent work (in million $+ homes), and charges about half price. Plenty like him around the country.


It's really the history of America, as every wave of Immigrants moved in. In a lot of cases (and I mean in many businesses- not just painting) you get your whole family involved and they are working cheap- if not just for room and board. Hard to compete with that when you and your help have so many real world bills to pay.


----------



## RH (Sep 7, 2010)

Gymschu said:


> I'm not saying this matches up with any kind of paint science, but, after painting for lo these many years and keeping track of paint/stain jobs I've done, well, I think you get an extra two years of service adding that 2nd coat. The mils, the evening out of the sheen, etc. simply gives an extra 2 years before a re-do. Is that worth it to you? Is it worth it to the customer? Hard to say for sure based on the extra cost that is added to do that second coat......just one painter's "feel" about it.


For some reason, I thought you were self employed. Come to find out, you were working for some guy called, “lo”. 




:devil3:


----------



## jr.sr. painting (Dec 6, 2013)

Lightningboy65 said:


> Always two coat the old asbestos. I've seen it look great with one coat and then quickly fade out within a year if you don't second coat.




We always do but now that you say that. That type of siding does appear to have a lot of fading from original color when it's repainted. I think it takes 2 coats to develop the low lusture sheen just right on siding. 


Sent from my iPhone using Tapatalk


----------



## Lightningboy65 (Mar 12, 2018)

Fman said:


> In a lot of cases (and I mean in many businesses- not just painting) you get your whole family involved and they are working cheap- if not just for room and board. Hard to compete with that when you and your help have so many real world bills to pay.


Main reason the Amish can underbid just about anybody. Not because of the old "they don't pay taxes" line. And many people believe that. They pay the same taxes as others, with the exception of FICA taxes. They don't participate in Medicare or Social Security, so they don't pay FICA. But at least they are paying all other taxes, unlike most illegals doing contract work.


----------



## MikeCalifornia (Aug 26, 2012)

Pete, you probably can get most paints to cover in one, especially spraying, but the issue always is sheen development. I have found with one spray coat of premium finishes, the touch up is always shinier. Two coats, the touch-ups are perfect and the customer gets the most protection. You can give them the option of just one coat, but really you are a high end guy, so I would price two coats what you normally do, then one coat slightly below, as you will still have to go through all the patch and cover with both systems. A second coat is not that much more time.


----------



## MikeCalifornia (Aug 26, 2012)

Woodco said:


> Is there test data comparing longevity of exterior wood two 3 mil coats dried between compared to a board with a single 6 mil wet coat? I've asked this a few times, and never got an answer...



The two coats that are 3mil dry would be 6mil wet each, so really you just comparing 1 coat vs. 2 coats. And yes all paint manufactures data is on two coats, but they obviously have data on many other scenerios other than 1 coat. Lots of specs they write are for 1, 2, 3, 4 coats depending on the need.


I painted a house a few years back, was in great shape just stucco. I normally would do two coats of acrylic and its done. This guy wanted his house done according to a spec written for commercial tilt-ups in Hawaii, I kid you not as his son-in-law was a contractor and recommended it. It was SW: 1.Loxon primer 2. Conflex elastomeric 3. Conflex elastomeric 4. Superpaint flat That was close to 30mils dry.


----------



## Woodco (Nov 19, 2016)

MikeCalifornia said:


> The two coats that are 3mil dry would be 6mil wet each, so really you just comparing 1 coat vs. 2 coats.


No, Im not. Im comparing two coats of 3 mil wet each, to one single coat of 6 mil, or whatever equal math. I cant find one shred of data, other than a the common statement of "two light coats are better than one heavy coat." I want to know if it actually affects the longevity, and if so, by how much. OR, if its just a guideline to prevent runs and sags.


----------



## PACman (Oct 24, 2014)

Woodco said:


> Is there test data comparing longevity of exterior wood two 3 mil coats dried between compared to a board with a single 6 mil wet coat? I've asked this a few times, and never got an answer...


Yes there is, but unfortunately such information is internal within the respective paint manufacturers. Information about their respective testing is a pretty closely guarded secret. But i would imagine that there would be such information available from the MPI. I haven't looked yet but they do pretty much the same testing as the manufacturers do. So they should have generic information available. I would think anyway.


----------



## PACman (Oct 24, 2014)

Lightningboy65 said:


> Main reason the Amish can underbid just about anybody. Not because of the old "they don't pay taxes" line. And many people believe that. They pay the same taxes as others, with the exception of FICA taxes. They don't participate in Medicare or Social Security, so they don't pay FICA. But at least they are paying all other taxes, unlike most illegals doing contract work.


And they have plenty of 11 and 12 year old sons doing the work for room and board! Free (to them) labor is their main advantage. That and they don't pay any attention to child labor laws.


----------



## PACman (Oct 24, 2014)

Woodco said:


> No, Im not. Im comparing two coats of 3 mil wet each, to one single coat of 6 mil, or whatever equal math. I cant find one shred of data, other than a the common statement of "two light coats are better than one heavy coat." I want to know if it actually affects the longevity, and if so, by how much. OR, if its just a guideline to prevent runs and sags.


Another reason for two coats is that if you get voids or pinholes and such in one coat, the second coat will usually fill them. I've always heard that it is easier to do two good coats than one absolutely perfect coat.


----------



## PACman (Oct 24, 2014)

Lightningboy65 said:


> Main reason the Amish can underbid just about anybody. Not because of the old "they don't pay taxes" line. And many people believe that. They pay the same taxes as others, with the exception of FICA taxes. They don't participate in Medicare or Social Security, so they don't pay FICA. But at least they are paying all other taxes, unlike most illegals doing contract work.


You got any good scrapple in your neck of the woods? It's getting hard to find in these parts.


----------



## Lightningboy65 (Mar 12, 2018)

PACman said:


> You got any good scrapple in your neck of the woods? It's getting hard to find in these parts.


https://www.countrystoremeats.com/

This is some of the best I've ever had. I've been eating it since I was a kid. For $20.00 flat rate they ship, if you can't find it in OH.


----------



## CApainter (Jun 29, 2007)

Paint film thickness recommendations begin with a bare wood, metal, or masonry substrate. The condition of an existing paint film determines if it needs to be removed or simply recoated. As long as the existing paint film is clean and dry, and at the adequate mil thickness from the bare substrate, it's up to the painter to determine what constitutes an adequate subsequent film coat, or two.


----------



## PACman (Oct 24, 2014)

Lightningboy65 said:


> https://www.countrystoremeats.com/
> 
> This is some of the best I've ever had. I've been eating it since I was a kid. For $20.00 flat rate they ship, if you can't find it in OH.


Thanks! I may have to give them a try. Someone told me a vendor at the Hartville flea market had it so maybe i can get some next week. All the local Amish & farm markets can't sell it anymore because of the damn state of Ohio.


----------



## PACman (Oct 24, 2014)

CApainter said:


> Paint film thickness recommendations begin with a bare wood, metal, or masonry substrate. The condition of an existing paint film determines if it needs to be removed or simply recoated. As long as the existing paint film is clean and dry, and at the adequate mil thickness from the bare substrate, it's up to the painter to determine what constitutes an adequate subsequent film coat, or two.


Do you have any good scrapple?


----------



## CApainter (Jun 29, 2007)

PACman said:


> Do you have any good scrapple?


 
So, how does this relate to the thread? I'm not getting the inside joke.


----------



## Lightningboy65 (Mar 12, 2018)

PACman said:


> Thanks! I may have to give them a try. Someone told me a vendor at the Hartville flea market had it so maybe i can get some next week. All the local Amish & farm markets can't sell it anymore because of the damn state of Ohio.


I've had some good stuff from the local Amish, but none any better than the Country store stuff....they are big enough to be consistent, but small enough to still care about producing a top notch product. Their ring bologna is right at the top too.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> So, how does this relate to the thread? I'm not getting the inside joke.


Because in order to put on two coats, one needs a good breakfast.:glasses:


----------



## NACE (May 16, 2008)

Woodco said:


> Is there test data comparing longevity of exterior wood two 3 mil coats dried between compared to a board with a single 6 mil wet coat? I've asked this a few times, and never got an answer...


The US Forestry Service has details studies on this. They give analysis of how long wood was exposed without protection, long term success on one versus two coats on different species of wood in different parts of the country. Paint companies do extensive exterior testing however they start with a new surface not a re-coat of existing systems. It’s not an easy study to find but it is available. Includes both paint and stains oil and latex.


----------



## Lightningboy65 (Mar 12, 2018)

NACE said:


> The US Forestry Service has details studies on this. They give analysis of how long wood was exposed without protection, long term success on one versus two coats on different species of wood in different parts of the country. Paint companies do extensive exterior testing however they start with a new surface not a re-coat of existing systems. It’s not an easy study to find but it is available. Includes both paint and stains oil and latex.


I found a USFS study that rated different species of lumber and their ability to hold paint, but none that offered a one coat vs. two component.


----------



## PACman (Oct 24, 2014)

CApainter said:


> So, how does this relate to the thread? I'm not getting the inside joke.


Vegans don't like scrapple.


----------



## CApainter (Jun 29, 2007)

I'll make it really simple


1. Wood, metal, and masonry materials that have not been painted (Usually referred to as a "Bare Substrate") generally require several coats of paint. Sometimes called a coating system.


2. If a coating system was already applied to a bare substrate, it is likely that a particular thickness of paint (also known as "Dry Film Thickness") exists on that substrate. Provided there is no peeling paint and or significantly deterioration of the paint.


3. Therefore, film thickness (beyond the manufacturer's recommendation for previously painted "surfaces") is not as important when recoating.


This is why it is important to know the difference between a "Surface" and a "Substrate". 


Now go enjoy your scrapple.


----------



## Brushman4 (Oct 18, 2014)

PACman said:


> Thanks! I may have to give them a try. Someone told me a vendor at the Hartville flea market had it so maybe i can get some next week. All the local Amish & farm markets can't sell it anymore because of the damn state of Ohio.


Is this enough scrapple for you? https://www.best-price.com/search/l...Amazon&utm_term=scrapple&utm_content=scrapple

Looks like dog food and or Spam!


----------



## Woodco (Nov 19, 2016)

NACE said:


> The US Forestry Service has details studies on this. They give analysis of how long wood was exposed without protection, long term success on one versus two coats on different species of wood in different parts of the country. Paint companies do extensive exterior testing however they start with a new surface not a re-coat of existing systems. It’s not an easy study to find but it is available. Includes both paint and stains oil and latex.


I've seen lots of studies, none of them have what Im asking about....


----------



## Lightningboy65 (Mar 12, 2018)

Brushman4 said:


> Is this enough scrapple for you? https://www.best-price.com/search/l...Amazon&utm_term=scrapple&utm_content=scrapple
> 
> Looks like dog food and or Spam!


That looks like something someone from Chi-town would say!:biggrin:

There is plenty of scrapple out there to be had....but precious little _good_ scrapple. It's one of those things that is I have to explain it to you, you just wouldn't understand.


----------



## RH (Sep 7, 2010)

PACman said:


> You got any good scrapple in your neck of the woods? It's getting hard to find in these parts.


Isn’t that sort of an oxymoron? :wink:


----------



## PACman (Oct 24, 2014)

Brushman4 said:


> Is this enough scrapple for you? https://www.best-price.com/search/l...Amazon&utm_term=scrapple&utm_content=scrapple
> 
> Looks like dog food and or Spam!


all that mass produced stuff is lame. Doesn't have any lungs in it. It's kind of like the difference between top Wisconsin cheddar and velveta.


----------



## PACman (Oct 24, 2014)

Lightningboy65 said:


> That looks like something someone from Chi-town would say!:biggrin:
> 
> There is plenty of scrapple out there to be had....but precious little _good_ scrapple. It's one of those things that is I have to explain it to you, you just wouldn't understand.


exactly! If you've ever had home made scrapple nothing else will do. My grandmother made her own. With some homemade maple syrup it was heaven on earth!


----------



## PACman (Oct 24, 2014)

Brushman4 said:


> Is this enough scrapple for you? https://www.best-price.com/search/l...Amazon&utm_term=scrapple&utm_content=scrapple
> 
> Looks like dog food and or Spam!


Do you eat sausage? It's pretty much the same thing. Texture is a little different because it has corn or oat meal in it. Not wrapped in pig rectum like sausage is though so you lose that little nuance. Does have rectum in it though. The good stuff does anyway.

If you were lucky and you were at grandma's house while she was boiling the hog head to make it, she would pull you off a piece of cheek meat! Boy that was some damn good eatin'! Best meat on the planet! Screw that Japanese beef crap!


----------



## Lightningboy65 (Mar 12, 2018)

PACman said:


> a piece of cheek meat! Boy that was some damn good eatin'! Best meat on the planet! Screw that Japanese beef crap!


Truer words have never graced these pages!!! Amen.


----------



## PACman (Oct 24, 2014)

Lightningboy65 said:


> Truer words have never graced these pages!!! Amen.


Once you've had it, you know!


----------



## Lightningboy65 (Mar 12, 2018)

PACman said:


> Once you've had it, you know!


If you're ever at a pig roast, that is the first thing to go for. Those in the know, know.:vs_OMG:


----------



## Wildbill7145 (Apr 30, 2014)

Lightningboy65 said:


> If you're ever at a pig roast, that is the first thing to go for. Those in the know, know.:vs_OMG:



We roasted a pig for our wedding reception. I seem to remember the thing took over 8hrs to cook and a several hours to prepare. We named her Delia.


People still say that was the best wedding reception food they ever had.


----------



## Brushman4 (Oct 18, 2014)

PACman said:


> all that mass produced stuff is lame. Doesn't have any lungs in it. It's kind of like the difference between top Wisconsin cheddar and velveta.


Ya, a Wisconsin Extra Sharp Cheddar is great, but Velveta melts better.


----------



## PACman (Oct 24, 2014)

Lightningboy65 said:


> If you're ever at a pig roast, that is the first thing to go for. Those in the know, know.:vs_OMG:


damn i'm getting hungry! No hog cheek restaurants nearby though!


----------



## PACman (Oct 24, 2014)

Wildbill7145 said:


> We roasted a pig for our wedding reception. I seem to remember the thing took over 8hrs to cook and a several hours to prepare. We named her Delia.
> 
> 
> People still say that was the best wedding reception food they ever had.


I went to a Filipino wedding when i was in San Diego. They traditionally serve a hogs head or two. When they offered me some cheek and i said hell ya they looked at me like i was some crazy white boy! "what does some white boy from Ohio know about pig cheek?" They had never seen any one from the US eat it! I was all over that 5hit! No balut though! No way!


----------



## BrushPro (Nov 15, 2018)

I don't even offer one coat bids unless they are really adamant about it. Two coats is just the right way, looks the best, and provides more hours of work in the long haul for you and more money. Better look, better reputation, less future issues equals a better painting business with higher prices that makes good money.


----------



## PACman (Oct 24, 2014)

BrushPro said:


> I don't even offer one coat bids unless they are really adamant about it. Two coats is just the right way, looks the best, and provides more hours of work in the long haul for you and more money. Better look, better reputation, less future issues equals a better painting business with higher prices that makes good money.


and what does that have to do with pig faces? Oh.....nevermind.


----------



## APPNW (Jul 9, 2019)

I tried balut once in the phillippines. Tasted great, but when i crunched down on the beak i was like wtf!? I looked down at what i was eating and at the same time it fell out of the shell onto my lap.... ill spare the rest of the details... needless to say that was a wrap


----------



## APPNW (Jul 9, 2019)

BrushPro said:


> I don't even offer one coat bids unless they are really adamant about it. Two coats is just the right way, looks the best, and provides more hours of work in the long haul for you and more money. Better look, better reputation, less future issues equals a better painting business with higher prices that makes good money.


I like your use of words sir.
That was very well said.


----------



## Lightningboy65 (Mar 12, 2018)

Guanciale is Italian bacon made from the cheek and jowl . And it is , of course, delicious.


----------



## Woodco (Nov 19, 2016)

BrushPro said:


> I don't even offer one coat bids unless they are really adamant about it. Two coats is just the right way, looks the best, and provides more hours of work in the long haul for you and more money. Better look, better reputation, less future issues equals a better painting business with higher prices that makes good money.


Do you spray exteriors?


----------



## Brushman4 (Oct 18, 2014)

PACman said:


> I went to a Filipino wedding when i was in San Diego. They traditionally serve a hogs head or two. When they offered me some cheek and i said hell ya they looked at me like i was some crazy white boy! "what does some white boy from Ohio know about pig cheek?" They had never seen any one from the US eat it! I was all over that 5hit! No balut though! No way!


I was at a Serbian wedding where they served a whole pig, I like a pork chop, pulled pork and a pork roast every now and then, not a fan of a whole pig. However, it did provide a lot of laughs when everyone was half in the bag and us guys took turns chasing the girls around with the head!
If you don't know, Slivovitz can give you a nasty hangover.


----------



## Lightningboy65 (Mar 12, 2018)

Brushman4 said:


> However, it did provide a lot of laughs when everyone was half in the bag and us guys took turns chasing the girls around with the head!


Better be careful, in some cultures you're considered married after pursuing a female with a pig's head!:surprise:


----------



## MikeCalifornia (Aug 26, 2012)

Woodco said:


> No, Im not. Im comparing two coats of 3 mil wet each, to one single coat of 6 mil, or whatever equal math. I cant find one shred of data, other than a the common statement of "two light coats are better than one heavy coat." I want to know if it actually affects the longevity, and if so, by how much. OR, if its just a guideline to prevent runs and sags.



Your post said two coats of 3mil dry, but semantics aside, PAC gave a better reason for two coats. I don't think you can go off of your common statement, as who can say what a light coat is vs a heavy coat? Really a coat of paint is a coat of paint regardless how thick the product is or how you apply it.


----------



## Lightningboy65 (Mar 12, 2018)

MikeCalifornia said:


> Your post said two coats of 3mil dry, but semantics aside, PAC gave a better reason for two coats. I don't think you can go off of your common statement, as who can say what a light coat is vs a heavy coat? Really a coat of paint is a coat of paint regardless how thick the product is or how you apply it.


 I realize many on PaintTalk may not deal with projects that involve mil spec inspections, those that do realize a coat of paint is not a coat of paint. If working a mil spec job, you had better be certain you are putting it on thick enough.

And not only to pass inspection. Some coatings, elastomerics for example, will not perform as they should if millage is not high enough. And I feel a thicker coat, in most cases, is superior to a thinner coat. No data to back that one up, just my gut feeling.

Dip it to the chrome, and put it on like you're not payin' for it. Because you're not payin for it. If you did your estimating right, the customer is!


----------



## Brushman4 (Oct 18, 2014)

:biggrin:


Lightningboy65 said:


> Better be careful, in some cultures you're considered married after pursuing a female with a pig's head!:surprise:


Well, I was already married at the time, so are you saying I could have had a harem?:biggrin:


----------



## Woodco (Nov 19, 2016)

MikeCalifornia said:


> Your post said two coats of 3mil dry, but semantics aside, PAC gave a better reason for two coats. I don't think you can go off of your common statement, as who can say what a light coat is vs a heavy coat? Really a coat of paint is a coat of paint regardless how thick the product is or how you apply it.


Well, apparently its rocket surgery trying to grasp what Im asking for... 

Two boards. Lets say they were both primed with the same product....

The SAME THICKNESS of paint is applied on each. 

ONE was sprayed twice with proper drytime in between to get said thickness, the other was sprayed ONCE... 

The important thing to remember is that they have the EXACT SAME Millage of paint. Lets say they used a calibrated mil tester...

Now set the boards outside for several years. Compare longevity, fading, peeling etc. What is the difference between the two, and how significant is it? Im talking DATA, not theories, guesses, 'you'd think...' or 'blah, blah, blah, warranty..' . It can be either a Hillbilly lab test, or scientific study. Has it been done or not? Im so incredibly frustrated that people dont understand what Im asking for.


----------



## CApainter (Jun 29, 2007)

Woodco said:


> Well, apparently its rocket surgery trying to grasp what Im asking for...
> 
> Two boards. Lets say they were both primed with the same product....
> 
> ...


This makes total sense to me.

And to understand correctly, Woodco is asking what affect the same time line and exposure has on two different boards that were painted with an identical coating system with identical total Dry Film Thickness. But, with the exception that one board had a single Wet Film Thickness application compared to the other board that had two separate WFT applications with appropriate dry times in between.

What makes the difference in the two applications is that the single WFT may have had it's full film formation compromised due to solvent entrapment compared to the two coat WFT application recommended by the manufacturer's TDS.

For example, trying to push a coating's recommended WFT, can result in a "cake" phenomena where the shell cures to a relatively hard surface, but leaves the middle a little soft. Obviously, the designed performance of a coating in this condition has been compromised. Unfortunately, this is all at a molecular level that is hardly recognized by a painter who simply rubs their paw over a dried painted surface.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> This makes total sense to me.
> 
> And to understand correctly, Woodco is asking what affect the same time line and exposure has on two different boards that were painted with an identical coating system with identical total Dry Film Thickness. But, with the exception that one board had a single Wet Film Thickness application compared to the other board that had two separate WFT applications with appropriate dry times in between.
> 
> ...


Or it could be that the cross linking properties between the two coats ,in the total film thickness, are compromised by applying the film in two coats. Any supposition without a controlled scientific test is merely just that, supposition. And it appears for reasons unknown, these test results, should they exist, are a closely guarded secret. Perhaps we should employ the Russians to dig them up.

For the record, I _feel_ two thinner coats are better. Unfortunately I have no empirical data to back up my hypothesis.:glasses:


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> Or it could be that the cross linking properties between the two coats ,in the total film thickness, are compromised by applying the film in two coats. Any supposition without a controlled scientific test is merely just that, supposition. And it appears for reasons unknown, these test results, should they exist, are a closely guarded secret. Perhaps we should employ the Russians to dig them up.
> 
> For the record, I _feel_ two thinner coats are better. Unfortunately I have no empirical data to back up my hypothesis.:glasses:


Single component paint films cure by coalescence (evaporation of solvents) rather than by chemical crosslinking that typically occurs with two component coatings.

For single component waterborne coatings, adhesion of subsequent coats of paint rely on penetration into the micro-perforated film matrix of the first, provided that most if not all of the first coat solvents have evaporated.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> Single component paint films cure by coalescence (evaporation of solvents) rather than by chemical crosslinking that typically occurs with two component coatings.
> 
> For single component waterborne coatings, adhesion of subsequent coats of paint rely on penetration into the micro-perforated film matrix of the first, provided that most if not all of the first coat solvents have evaporated.


Many of the newer latex coatings employ crosslink technology - at least that's what the labels claim. Duration and Valspar Hi-Def are two that come to mind. 

And who's to say the bond of the second coat to the micro-perforated film matrix of the first is better than having only one thicker coat where that bond interface is non existent? If testing has been done, the results are not readily available.


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> Many of the newer latex coatings employ crosslink technology - at least that's what the labels claim. Duration and Valspar Hi-Def are two that come to mind.
> 
> And who's to say the bond of the second coat to the micro-perforated film matrix of the first is better than having only one thicker coat where that bond interface is non existent? If testing has been done, the results are not readily available.


To your first point. It's a good point. Today's technology capabilities offer interesting ways to integrate components that were traditionally incompatible.

But to your second point, and generally speaking, the science of thermoplastic film formation requires that the vehicle solvents fully evaporate during coalescing. What we read in the product TDS, in terms of WFT and DFT, and recoat times, are the results of Lab testing that provided the best performance outcomes from the coating. It also provides a guide line for recourse if there were a failure to occur.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> But to your second point, and generally speaking, the science of thermoplastic film formation requires that the vehicle solvents fully evaporate during coalescing. What we read in the product TDS, in terms of WFT and DFT, and recoat times, are the results of Lab testing that provided the best performance outcomes from the coating.


I have a _feeling_ this is generally true, and for this reason have 
always personally held to the personal practice of two thinner coats. 

As to this lab testing you speak of ...where are these studies and the resulting data??? I have found it virtually impossible to track down the actual lab tests, and more importantly the empirical data???


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> I have a _feeling_ this is generally true, and for this reason have
> always personally held to the personal practice of two thinner coats.
> 
> As to this lab testing you speak of ...where are these studies and the resulting data??? I have found it virtually impossible to track down the actual lab tests, and more importantly the empirical data???



It's true, and often lamented by painters, that controlled environment testing doesn't represent real world conditions. But I suppose there needs to be a level of trust involved in laboratory testing. For example, airstream testing over the wings of a Boing 757 hopefully provide a pretty good idea of what will occur at 30,000 ft.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> But to your second point, and generally speaking, the science of thermoplastic film formation requires that the vehicle solvents fully evaporate during coalescing. What we read in the product TDS, in terms of WFT and DFT, and recoat times, are the results of Lab testing that provided the best performance outcomes from the coating. It also provides a guide line for recourse if there were a failure to occur.


Since traditional latex paints do not involve thermosetting mechanisms, and rely on evaporation to cure, this really wouldn't apply to traditional latex house paint. 

Well ,the solvents would need to be fully evaporated, but thermoplastics has nothing to do with it.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> It's true, and often lamented by painters, that controlled environment testing doesn't represent real world conditions. But I suppose there needs to be a level of trust involved in laboratory testing. For example, airstream testing over the wings of a Boing 757 hopefully provide a pretty good idea of what will occur at 30,000 ft.


Agreed, but it would be nice to see the actual test outcomes.:sad:


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> Since traditional latex paints do not involve thermosetting mechanisms, and rely on evaporation to cure, this really wouldn't apply to traditional latex house paint.
> 
> Well ,the solvents would need to be fully evaporated, but thermoplastics has nothing to do with it.


Single component coatings, including those with latex and acrylic resins, are considered thermoplastic materials because they can be returned to their original state, or something like that. On the other hand, thermoset plastic materials like two component epoxies, can't be reduced to their original state because of the conversion process through chemical crosslinking. This is why they are referred to as conversion coatings.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> Single component coatings, including those with latex and acrylic resins, are considered thermoplastic materials because they can be returned to their original state, or something like that.


We will just have to agree to disagree on this point.:wink:


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> Agreed, but it would be nice to see the actual test outcomes.:sad:


I had the opportunity back in the early 80's, to visit the Kelly Moore laboratory in Santa Clara CA. It was pretty interesting, but probably nothing compared to PACman's Hillbilly lab. I can only imagine all kinds of biological parts immersed in jars of formaldehyde right next to a test board of BEHR Premium paint that lord knows what it was subjected to. "Brrrr"


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> We will just have to agree to disagree on this point.:wink:


You still have a chance to get on board.

Resourced from Wikipedia:
*Poly(methyl methacrylate) (PMMA),* also known as acrylic, acrylic glass, or plexiglass as well as by the trade names Crylux, Plexiglas, Acrylite, Lucite, and Perspex among several others (see below),* is a transparent thermoplastic *often used in sheet form as a lightweight or shatter-resistant alternative to glass. The same material can be used as a casting resin, in inks and *coatings,* and has many other uses.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> You still have a chance to get on board.
> 
> Resourced from Wikipedia:
> *Poly(methyl methacrylate) (PMMA),* also known as acrylic, acrylic glass, or plexiglass as well as by the trade names Crylux, Plexiglas, Acrylite, Lucite, and Perspex among several others (see below),* is a transparent thermoplastic *often used in sheet form as a lightweight or shatter-resistant alternative to glass. The same material can be used as a casting resin, in inks and *coatings,* and has many other uses.


Is that on the same innerwebs that Al Gore invented?:biggrin:

In its pure form, PMMA is indeed a thermoplastic. Using it as a component of latex paint does not make that paint subject to the to curative properties of thermoplastic materials.


----------



## RH (Sep 7, 2010)

So much passion expended on something probably 98% of us never even think about - actual mil thickness.

Guess I’m just a hack for admitting I never once used, let alone owned, a device to measure the thickness of coatings. But then I never did jobs requiring specific thicknesses. I just pretty much always did (and do) two coats in the belief that it looked and held up better. Tests saying one thing over another likely never would have made a difference to me and certainly wouldn’t have resulted in major changes in my process.


----------



## Lightningboy65 (Mar 12, 2018)

RH said:


> So much passion expended on something probably 98% of us never even think about - actual mil thickness.
> 
> Guess I’m just a hack for admitting I never once used, let alone owned, a device to measure the thickness of coatings. But then I never did jobs requiring specific thicknesses. I just pretty much always did (and do) two coats in the belief that it looked and held up better. Tests saying one thing over another likely never would have made a difference to me and certainly wouldn’t have resulted in major changes in my process.


But imagine all the time saved if indeed it were revealed through scientific testing that a single 6 mil coat was as good or better than two 3 mil coats!

Also imagine all of the additional runs and drips!:biggrin:

Unfortunately ,I had to deal with mil specs more than I would have liked!:sad:


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> Is that on the same innerwebs that Al Gore invented?:biggrin:
> 
> In its pure form, PMMA is indeed a thermoplastic. Using it as a component of latex paint does not make that paint subject to the to curative properties of thermoplastic materials.


But because PMMA is a major component of a WB Acrylic paint resin, it places that coating in the thermoplastic category verses the thermoset plastic category. That's just scientific fact. I learned this from the SSPC C1 Coatings course I took some time back. It isn't really all that relevant to know this information, but it offers good material for internet debates. lol!


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> But imagine all the time saved if indeed it were revealed through scientific testing that a single 6 mil coat was as good or better than two 3 mil coats!
> 
> Also imagine all of the additional runs and drips!:biggrin:
> 
> Unfortunately ,I had to deal with mil specs more than I would have liked!:sad:


Coatings designed to be applied at a single WFT of 20, 40, and higher mils already exist. It's all about the SBV%.


----------



## CApainter (Jun 29, 2007)

RH said:


> So much passion expended on something probably 98% of us never even think about - actual mil thickness.
> 
> Guess I’m just a hack for admitting I never once used, let alone owned, a device to measure the thickness of coatings. But then I never did jobs requiring specific thicknesses. I just pretty much always did (and do) two coats in the belief that it looked and held up better. Tests saying one thing over another likely never would have made a difference to me and certainly wouldn’t have resulted in major changes in my process.


Usually, industrial paint jobs have coating inspectors that inspect mil thickness and require the painters to have the WFT and DFT gauges on site. It's all about liability because these projects are often difficult to access, like the interior of water distribution piping and large storage tanks, including large and remote critical structures that can't be subject to regular inspection or maintenance.

So for painters who have been exposed to those kind of projects and may now be painting architectural, it's natural to think about coating thickness along with aesthetic outcome.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> Coatings designed to be applied at a single WFT of 20, 40, and higher mils already exist. It's all about the SBV%.


I was referring to regular old house paints, which if you had a bunch of guys "puttin' it thick" would definitely result in a higher incident of runs, droops,and drips

But yeah, some coatings are designed to go on thick without adverse consequences.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> But because PMMA is a major component of a WB Acrylic paint resin, it places that coating in the thermoplastic category verses the thermoset plastic category. That's just scientific fact. I learned this from the SSPC C1 Coatings course I took some time back. It isn't really all that relevant to know this information, but it offers good material for internet debates. lol!


I can dig that, bro. It might put them in that category, but they really don't adhere to the curative properties of such. The PMMA is in suspension, not solution. The PMMA in the paint is already cured. Only the paint itself needs to cure, not the PMMA.


----------



## CApainter (Jun 29, 2007)

Lightningboy65 said:


> I can dig that, bro. It might put them in that category, but they really don't adhere to the curative properties of such. The PMMA is in suspension, not solution. The PMMA in the paint is already cured. Only the paint itself needs to cure, not the PMMA.


But what is dried paint? It's the resin, pigment, binders, and additives left behind after the vehicle solvent has evaporated. Essentially, a solid Acrylic film.


----------



## Lightningboy65 (Mar 12, 2018)

CApainter said:


> But what is dried paint? It's the resin, pigment, binders, and additives left behind after the vehicle solvent has evaporated. Essentially, a solid Acrylic film.


Upon reviewing post # 82, this post,and getting things straight in my head, all I can say is...I agree.

I was confusing thermoplastic and thermoset plastic.:surprise:


----------



## PACman (Oct 24, 2014)

OK talking about plain ol' house paints. If one coat of paint is applied to thick, there is the possibility that the paint in the middle of the coat may not cure properly or at all. That is the main reason that paint companies usually recommend two light coats as opposed to one thick coat. This does if course not apply to the newer paints such as Timeless and Duration as they are engineered to cure properly and completely at 6-8 mils wet, which is pretty much a traditional two coat mil thickness. The jury is still out on the box store paints that claim this capability, as i have found them to be lacking in hardness and adhesion compared to Timeless and Duration.


----------



## Brushman4 (Oct 18, 2014)

PACman said:


> OK talking about plain ol' house paints. If one coat of paint is applied to thick, there is the possibility that the paint in the middle of the coat may not cure properly or at all. That is the main reason that paint companies usually recommend two light coats as opposed to one thick coat. This does if course not apply to the newer paints such as Timeless and Duration as they are engineered to cure properly and completely at 6-8 mils wet, which is pretty much a traditional two coat mil thickness. The jury is still out on the box store paints that claim this capability, as i have found them to be lacking in hardness and adhesion compared to Timeless and Duration.


Timeless is sold at Home Depot, doesn't this qualify as a big box store?


----------



## Woodco (Nov 19, 2016)

Brushman4 said:


> Timeless is sold at Home Depot, doesn't this qualify as a big box store?


The home depot timeless is interior. I dont think they sell the real exterior timeless there.


----------



## Brushman4 (Oct 18, 2014)

Woodco said:


> The home depot timeless is interior. I dont think they sell the real exterior timeless there.


https://www.homedepot.com/p/PPG-Tim...IvSARNB55aSwPt8wuiRoCKxoQAvD_BwE&gclsrc=aw.ds


----------



## PACman (Oct 24, 2014)

Brushman4 said:


> Timeless is sold at Home Depot, doesn't this qualify as a big box store?


i guess it is now isn't it! Thanks for reminding me. TIMELESS SUCKS NOW PEOPLE! But seriously, i bet they've (PPG) already cheapened the hell out of it.


----------



## PACman (Oct 24, 2014)

Brushman4 said:


> https://www.homedepot.com/p/PPG-Tim...IvSARNB55aSwPt8wuiRoCKxoQAvD_BwE&gclsrc=aw.ds


"wood stain & sealant in one!" Jesus what next?


----------



## Brushman4 (Oct 18, 2014)

PACman said:


> "wood stain & sealant in one!" Jesus what next?


I think they're coming out with a sanding ingredient, so it will be wood stain, sealant, and sanding in one.


----------



## Woodco (Nov 19, 2016)

Wasnt PPG renaming Flood stains? I wonder if this is it...


----------



## PACman (Oct 24, 2014)

Woodco said:


> Wasnt PPG renaming Flood stains? I wonder if this is it...


PPG is renaming everything this coming year! There will be no other brand names than PPG on any of their products unless a customer requests it. No more Porter, No more Glidden, no more nothing. And they are discontinuing a bunch of products they feel are redundant and replacing them with a former Pittsburgh paint equivalent.


----------

