# Can You Actually Thin Paint Too Much?



## rwransom (Aug 7, 2013)

I'm spraying SW ProClassic Hybrid with a big air compressor (20 CFM @ 90) and an auto gun. To get proper atomization I'm thinning it a lot maybe 30%.

My theory is this: 

I don't think you can overthin water based paint. It may take more coats to achieve the desired mils (and associated performance) but thinning shouldn't affect the chemistry itself.

Why? Because paint is pigment + binder (what holds the pigment to the painted surface) + carrier (water). The carrier evaporates off any way so it shouldn't matter how much carrier is present. All we care about is what is left after the carrier evaporates.

Any one have a different idea?


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## Boco (May 18, 2013)

Thinning 30% seems a bit much. Not sure why you would think more coats would be better. Maybe adjusting your spray pattern and air would be easier. What kind of gun do you have?


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## PNW Painter (Sep 5, 2013)

Have you looked into SW Kem Aqua Plus? I'm wondering if it might be a better product to spray with your equipment. 


Sent from my iPhone using Tapatalk


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## JourneymanBrian (Mar 16, 2015)

yes of course you can. After a certain point you dont have enough binder to bind your pigments. The surface will chalk.


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## robladd (Nov 22, 2010)

It sounds to me your spray nozzle is too small. 20 cfm is plenty of volume but 90 psi is a bit high. When I spray WB with convention air spray I thin about 10% use 50 psi. 

I use a nozzle for WB material. Too much reduction in my experience changes the sheen. Semi Gloss to Satin, Satin to Flat.

Your results may vary but I would check out my work a few days later and see how well the coating is holding up.


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## JourneymanBrian (Mar 16, 2015)

rwransom said:


> I'm spraying SW ProClassic Hybrid with a big air compressor (20 CFM @ 90) and an auto gun. To get proper atomization I'm thinning it a lot maybe 30%.
> 
> My theory is this:
> 
> ...


Ok Im revising my position. You also have less pigments when you thin with water.

As long as you dont thin with solvent (floetrol?) you should be good...


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## PACman (Oct 24, 2014)

yes you can over thin water based paints.


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## Gough (Nov 24, 2010)

JourneymanBrian said:


> Ok Im revising my position. You also have less pigments when you thin with water.
> 
> As long as you dont thin with solvent (floetrol?) you should be good...


At some point, thinning will leave to a film lacking in both cohesion and adhesion.

This isn't an issue with products like lacquer and shellac, since each application dissolves the previous ones, "melting" together.


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## DrakeB (Jun 6, 2011)

To be more specific (if anyone cares), when waterborne paint dries it forms a crystalline lattice that gives it its strength. If you over-thin it, the molecules will be too dispersed and it won't have enough of the binder to form a film when it dries. Putting on more coats won't help, because each coat has to stand on its own merit. If you put more coats on, it will simply create more stress on each layer, increasing the likelihood of failure.

To put it in a simple example for those not interested in the science, it would be like trying to put wallpaper on by only dabbing glue (just kidding, it's paste ) in one little spot every 2 feet on the wall. Your wallpaper is going to bubble and fall off (or just chalk and flake more likely).


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## Wildbill7145 (Apr 30, 2014)

DrakeB said:


> To put it in a simple example for those not interested in the science, it would be like trying to put wallpaper on by only dabbing glue (just kidding, it's paste ) in one little spot every 2 feet on the wall. Your wallpaper is going to bubble and fall off (or just chalk and flake more likely).


That would however make it easier for removal when the decision to convert to paint is made. :whistling2:


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## Mike2coat (Nov 12, 2013)

I thinned the hell out of some exterior WB All Surface Enamel in a pinch and got a crackling effect lol


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## Mike2coat (Nov 12, 2013)

Mike2coat said:


> I thinned the hell out of some exterior WB All Surface Enamel in a pinch and got a crackling effect lol


 well I thinned it with WB flotral.


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## DrakeB (Jun 6, 2011)

Wildbill7145 said:


> That would however make it easier for removal when the decision to convert to paint is made. :whistling2:


Maybe it was a bad analogy, because that could only be a good thing.


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## Wildbill7145 (Apr 30, 2014)

I honestly only remember thinning two paints since I started painting.

One was Aura when I first started using it and it was driving me insane with the super fast dry time. Once I got used to it after a few jobs I never did that again.

The other was oil floor paint where the instructions called for the first coat to be thinned 10%. Wow, did that smell.

I just don't see the point in thinning paint when the goal is to get two solid coats on whatever surface your doing, but then again I've never sprayed anything in my life.


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## DrakeB (Jun 6, 2011)

Yeh, much more of an issue when you're spraying. I've never thinned anything to lay out with a brush or roller; but then again, I'm not a painter


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## JourneymanBrian (Mar 16, 2015)

Thinning oils is supposed to get you deeper penetration.

Linseed oil is also often heated for this purpose before applying (lowers viscosity).


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## CApainter (Jun 29, 2007)

I would argue that over thinning can compromise the thermodynamics occuring during the vehicle evaporation and subsequent coalescense critical to film formation.

Using my pale porpoise like body as an example, dousing myself with large amounts of water will not cool me down any more then the controlled beads of evaporating persperation will. In fact, the excess water retards the thermodynamics that result in heat transfer through vapor release.

It is important not to exceed the allowable ratio of vehicle solvents for similar reasons.


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## Gough (Nov 24, 2010)

CApainter said:


> I would argue that over thinning can compromise the thermodynamics occuring during the vehicle evaporation and subsequent coalescense critical to film formation.
> 
> Using my pale porpoise like body as an example, dousing myself with large amounts of water will not cool me down any more then the controlled beads of evaporating persperation will. In fact, the excess water retards the thermodynamics that result in heat transfer through vapor release.
> 
> It is important not to exceed the allowable ratio of vehicle solvents for similar reasons.


Sorry, John, while your point about excess vehicle/solvent is valid, your analogy is both bad and incorrect. Heat can leave your body by other routes besides evaporative cooling. In this case, conduction.


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## CApainter (Jun 29, 2007)

Gough said:


> Sorry, John, while your point about excess vehicle/solvent is valid, your analogy is both bad and incorrect. Heat can leave your body by other routes besides evaporative cooling. In this case, conduction.


But its more efficient when evaporated...winner!


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## Criard (Nov 23, 2013)

*pH IS IMPORTANT!!!*

Just to add another reason why you can and shouldn't overthin water based/borne paint;

They have a specific pH range that they function in. Too far below that range and you can have the resin or other raw materials settle out and be extremely difficult to reincorporate.

Floetrol or BM's extender would probably be a better option for extensive thinning as they have a proper pH and also contain some resins/binders to keep from weakening the paint.


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## DrakeB (Jun 6, 2011)

Good point Criard. BM's extender is made from the same (in house) materials as their paint, which does help a lot with compatibility as long as you're using it with their products. I'm not sure how well Floetrol meshes with most brands; I stock both, some people seem to prefer Floetrol (maybe just name association).


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## Jasonthep8nter (Aug 7, 2013)

Yes you can over thin wb paint, it says right on the label apply right from the can,if needed apply a SMALL amount of water. If you thin paint out to to much it's pretty much worthless since it can't do what it was designed to do


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## TKbrush (Dec 30, 2014)

I notice that some batches of duration and aura exterior are thicker than others, so i have been flinging a bit of water in the paint pot, alittle helps alot. Otherwise its way slow brushing with heavy paint and i lose accuracy with windows and doors. In hot weather the paint thickens up even more in the pot. With rolling, i just work the paint as much as i can, without thinning. Without knowing any science of paint, i would think the viscosity has something to do with its durability.


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## ewingpainting.net (Jun 2, 2008)

Paint these days are designed to be applied right out of the can, actually the coating falls apart when you over thin the paint. Some enamels lose their hang time with any amount of water. Most lables will tell you "sparingly" which tells me not to thin it unless absolutely necessary, and if needed it being less than 1%. Your comprising the coating when deviating from manufacturer recommendation. You lose all manufacturer support, widening the liability for potential failures. Doesn't take much for a coating to fail, over thinning is just promoting failure.


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## DrakeB (Jun 6, 2011)

ewingpainting.net said:


> Paint these days are designed to be applied right out of the can, actually the coating falls apart when you over thin the paint. Some enamels lose their hang time with any amount of water. Most lables will tell you "sparingly" which tells me not to thin it unless absolutely necessary, and if needed it being less than 1%. Your comprising the coating when deviating from manufacturer recommendation. You lose all manufacturer support, widening the liability for potential failures. Doesn't take much for a coating to fail, over thinning is just promoting failure.


To add to that, many TDS will have a maximum thinning amount for your application. I know modern BM paints do. And to tie into another thread nicely, as you mention, a company is going to ask how much you thinned their coating as a part of their normal questions if you have a product failure. When you say 30% they're going to laugh and walk away.


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## PACman (Oct 24, 2014)

I find that if I put too much water in my scotch I don't get drunk fast enough.


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## DrakeB (Jun 6, 2011)

Proalliance coatings said:


> I find that if I put too much water in my scotch I don't get drunk fast enough.


You people are so strange. Why are you putting other stuff in perfectly good liquor?


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## PACman (Oct 24, 2014)

DrakeB said:


> You people are so strange. Why are you putting other stuff in perfectly good liquor?


Because it's the correct way to drink scotch. a little spring water opens the bouquet. Look it up.


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## DrakeB (Jun 6, 2011)

That's what the ice is for.


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## PACman (Oct 24, 2014)

DrakeB said:


> That's what the ice is for.


You can't control the flavor of ice. That's why in Scotland it's traditional to actually have a spring water tap at the bar. Ideally, you would use the same spring water source the distillery used to make the scotch.

Like my moonshining ancestors. They used Ohio river water in their moonshine.


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## DrakeB (Jun 6, 2011)

Proalliance coatings said:


> You can't control the flavor of ice. That's why in Scotland it's traditional to actually have a spring water tap at the bar. Ideally, you would use the same spring water source the distillery used to make the scotch.
> 
> Like my moonshining ancestors. They used Ohio river water in their moonshine.


Couldn't you just put spring water in ice trays?

Mods, I'd like to ask that this thread title be changed to "Can you thin your liquor too little" please.


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## jacob33 (Jun 2, 2009)

I agree one can thin to much but I always thought the addatives like penetro did not hurt the paint like a solvent as a thinner. I would be willing to bet even if I did 50/50 penetrol and oil paint it would bound good and not fail. It would not cover but it would not fail. Penetrol can be used as primer by itself I know on bare metal.


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## Gough (Nov 24, 2010)

jacob33 said:


> I agree one can thin to much but I always thought the addatives like penetro did not hurt the paint like a solvent as a thinner. I would be willing to bet even if I did 50/50 penetrol and oil paint it would bound good and not fail. It would not cover but it would not fail. Penetrol can be used as primer by itself I know on bare metal.


We haven't used Penetrol for years, but the label used to talk about adding oil colors or oil paint to make penetrating stains. We used to take that route to make custom deck stains, adding cadmium red, for instance. We've also used it straight as a paintable water repellant on window sills and thresholds.

EDIT: the Australian website for Flood still lists all of those uses, the U.S. TDS, not so much.


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## jacob33 (Jun 2, 2009)

I use penetrol all the time. We brush lots of trim around hear. People do not like the sprayed look they think it looks mass produced and cheap. Thinning with penetrol get a nice look. It almost looks sprayed.


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## Gough (Nov 24, 2010)

jacob33 said:


> I use penetrol all the time. We brush lots of trim around hear. People do not like the sprayed look they think it looks mass produced and cheap. Thinning with penetrol get a nice look. It almost looks sprayed.


How do you deal with the yellowing?

A recently departed PC around here did a passel of kitchens, mostly white, and he used Penetrol liberally to help the leveling. His kitchens didn't turn yellow, they turned *orange*! They were startling to see.


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## jacob33 (Jun 2, 2009)

We probably only use 5% Penetrol at most. We warm the paint to help with leveling as well. Nobody seems to use pure white on trim and cabinets around here. Its almost always an off white that is borderline cream. We just did one westhighland white a sherwin williams color look it up if you get a chance that is a typical trim color around here. I think since it is already yellow the yellowing is not a noticable. It had 4/32 of deep yellow in a gallon.


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## daArch (Mar 15, 2008)

Gough said:


> How do you deal with the yellowing?
> 
> A recently departed PC around here did a passel of kitchens, mostly white, and he used Penetrol liberally to help the leveling. His kitchens didn't turn yellow, they turned *orange*! They were startling to see.


How much did he use?

I've used boiled linseed to help leveling and never had a discoloration. Sure with enough of any amber "extender" one could notice a change, but would have to be a diaper full, one would think.

(Penetrol, IMO, has too many driers in it)


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## jacob33 (Jun 2, 2009)

I take it most people do not use oil anymore than. I know I need to get with the modern times but I still love the oil paint.


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## jacob33 (Jun 2, 2009)

I have never used linseed oil does that help with leveling better than penetrol?


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## daArch (Mar 15, 2008)

jacob33 said:


> I take it most people do not use oil anymore than. I know I need to get with the modern times but I still love the oil paint.


I'm as stubborn and old school as you. Going so far as to "reconstitute" castrated oils so they look and act like the oils of our youth.

One of the (many) reasons I stopped the paint and went exclusively to wallpaper installation, was the degradation of oils and the inferiority of latex (there was no term "waterbornes") in 1990.

BUT since then the waterbornes have far evolved (generally speaking) into superior coatings than the castrated oils.

This spring as I have been catching up on house maint, I been trying to use up some old oils and some other left over waterbornes, and what I LOVE about using waterbornes is the lack of solvent fumes & odor. The quality of life after painting a room is far healthier than the old days when the whole house would be permeated with fumes of thinners and drying alkyds for up to three days after. 

I bet the life expectancy of painters has been increased by a decade for those that don't use oils.


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## daArch (Mar 15, 2008)

jacob33 said:


> I have never used linseed oil does that help with leveling better than penetrol?


I like it better. My OPINION is that it would flow off the brush better and take longer to dry, thus leveling better. The down side is that linseed increases the gloss (which is good sometimes) and encourages mold and mildew growth - those little organisms LOVE linseed oil.


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## Gough (Nov 24, 2010)

daArch said:


> How much did he use?
> 
> I've used boiled linseed to help leveling and never had a discoloration. Sure with enough of any amber "extender" one could notice a change, but would have to be a diaper full, one would think.
> 
> (Penetrol, IMO, has too many driers in it)


It took a while and was a particular problem in areas that didn't receive much natural light. I think that's due to the linseed oil content.

Not sure how much he used and, given his current situation, I'm not likely to find out.


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## daArch (Mar 15, 2008)

Gough said:


> It took a while and was a particular problem in areas that didn't receive much natural light. I think that's due to the linseed oil content.
> 
> Not sure how much he used and, given his current situation, I'm not likely to find out.


One problem we had with Penetrol was that when it started to dry, the paint got "heavy" and "sticky", so we'd put in more Penetrol, which would dry quicker, which would require more Penetrol . . . . . . it was like opiates :whistling2:


I can understand how when one starts using, they need more and more just to maintain. 

I do love Penetrol to "prep" raw muntin wood before glazing. That "sticky" point is a great time to lay on the snake.


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## JourneymanBrian (Mar 16, 2015)

linseed oil is also is known to yellow even stronger than alkyds.

The issue of thinning has to to be different with oils. They have far more binder percent-wise (waterbornes are resin/water emulsions).

At least with linseed, thinning even 50/50 for example will not cause problems in cohesion/adhesion.
You just have half the pigment binding strength at that concentration; if you thin an opaque coat down to half itll chalk.


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## TJ Paint (Jun 18, 2009)

.......


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## I paint paint (May 4, 2014)

TJ Paint said:


> .......


Someone needs to hose TJ down, posting such watered down imagery here.


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## PACman (Oct 24, 2014)

DrakeB said:


> Couldn't you just put spring water in ice trays?
> 
> Mods, I'd like to ask that this thread title be changed to "Can you thin your liquor too little" please.


Of course you can. But it is harder then you think to keep that ice from picking up flavors from the freezer. Even the plastic in the freezer itself can flavor ice.


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## PACman (Oct 24, 2014)

jacob33 said:


> I agree one can thin to much but I always thought the addatives like penetro did not hurt the paint like a solvent as a thinner. I would be willing to bet even if I did 50/50 penetrol and oil paint it would bound good and not fail. It would not cover but it would not fail. Penetrol can be used as primer by itself I know on bare metal.


Penetrol has a resin, unlike a solvent alone. That's why you can use much more of it as an additive and not harm the paint. BTW, it's great to put on gardening tools to keep them from rusting.


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## daArch (Mar 15, 2008)

Proalliance coatings said:


> Of course you can. But it is harder then you think to keep that ice from picking up flavors from the freezer. Even the plastic in the freezer itself can flavor ice.


I just put a mix of Clorox and fluoride in my lead ice trays. Why fight city hall ?


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## DrakeB (Jun 6, 2011)

Proalliance coatings said:


> Of course you can. But it is harder then you think to keep that ice from picking up flavors from the freezer. Even the plastic in the freezer itself can flavor ice.


So it's agreed- the _best_ way to drink you scotch is to have Scottish mountain spring water delivered in an oak barrel (to stay consistent with the scotch) to Canada, where it's frozen naturally, outdoors, in a remote and pollution-free area, and then have put back in the sealed oak barrel, then have it delivered to your house where you immediately mix the scotch and drink it.

Actually, I think I'll stick with gin. It's easier.


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## Gough (Nov 24, 2010)

DrakeB said:


> Actually, I think I'll stick with gin. It's easier.


Yup. Just add flavors to vodka:whistling2:


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## DrakeB (Jun 6, 2011)

Gough said:


> Yup. Just add flavors to vodka:whistling2:


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## PACman (Oct 24, 2014)

DrakeB said:


> So it's agreed- the _best_ way to drink you scotch is to have Scottish mountain spring water delivered in an oak barrel (to stay consistent with the scotch) to Canada, where it's frozen naturally, outdoors, in a remote and pollution-free area, and then have put back in the sealed oak barrel, then have it delivered to your house where you immediately mix the scotch and drink it.
> 
> Actually, I think I'll stick with gin. It's easier.


Of course if you are cheap you can just drink Canadian Club. (no offence Canada)


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## jacob33 (Jun 2, 2009)

daArch said:


> I'm as stubborn and old school as you. Going so far as to "reconstitute" castrated oils so they look and act like the oils of our youth.



I'm only 28 so I dont know what to think of this comment.:jester:


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## daArch (Mar 15, 2008)

jacob33 said:


> I'm only 28 so I dont know what to think of this comment.:jester:


WOW, new school old school. Outstanding :thumbsup:


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## I paint paint (May 4, 2014)

jacob33 said:


> I take it most people do not use oil anymore than. I know I need to get with the modern times but I still love the oil paint.





jacob33 said:


> I'm only 28 so I dont know what to think of this comment.:jester:





daArch said:


> WOW, new school old school. Outstanding :thumbsup:


No. No. Don't encourage him.

Natura semi. That's what all the kewl kids are doing nowadays.

:thumbup:


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## daArch (Mar 15, 2008)

I paint paint said:


> No. No. Don't encourage him.
> 
> Natura semi. That's what all the kewl kids are doing nowadays.
> 
> :thumbup:


Yah, you're right. 

Jacob, have a healthy life, use the waterbornes !

OH, and also ALWAYS wear knee pads ! ! ! :yes: :yes: :thumbup:


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## Gough (Nov 24, 2010)

daArch said:


> Yah, you're right.
> 
> Jacob, have a healthy life, use the waterbornes !
> 
> OH, and also ALWAYS wear knee pads ! ! ! :yes: :yes: :thumbup:


And ear protection....


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## daArch (Mar 15, 2008)

Gough said:


> And ear protection....


WHAT'S Infected? You have infected beer ???


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## jacob33 (Jun 2, 2009)

I wish I could find a waterborne paint that brushed good. Solo was good for a while but not anymore. I have not tried advanced yet maybe I need to. The proclassic hybrid is okay but doesnt dry very hard.


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## Gough (Nov 24, 2010)

daArch said:


> WHAT'S Infected? You have infected beer ???


For the fourth time, chicken!


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## DrakeB (Jun 6, 2011)

jacob33 said:


> I wish I could find a waterborne paint that brushed good. Solo was good for a while but not anymore. I have not tried advanced yet maybe I need to. The proclassic hybrid is okay but doesnt dry very hard.


The Advance is a great product, but plan to have a bit of a learning curve. It will dry nice and hard as long as you let it dry an appropriate length between coats.


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## PACman (Oct 24, 2014)

jacob33 said:


> I wish I could find a waterborne paint that brushed good. Solo was good for a while but not anymore. I have not tried advanced yet maybe I need to. The proclassic hybrid is okay but doesnt dry very hard.


P&L Accolade is very under rated when it comes to brush ability. I wish more painters would give it a try. It has traditionally been considered kind of expensive, but considering the fact that P&L hasn't had a price increase in almost ten years it is getting priced back into competition by the other paint brands. It brushes nice, lays out extremely well, and cures to a very hard finish. The hard part is finding a dealer that will work with you on price. It was updated a couple of years ago specifically to improve the flow and brushing "feel". Also, because it is not a hybrid or a urethane modified acrylic the learning curve is not as difficult to master.

If I had had the monetary capabilities to become a BM dealer when I opened, I would have loved to be able to carry Advance. But I have been very pleasantly surprised by how well the Accolade performs.


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