# Need advice on exterior surface prep



## vincenzocustoms (May 7, 2015)

Hey all, I recently took on a pretty rough exterior, paint peeling cracking chipping etc, took the power washer to it and yeah im looking for some advice on how I should go about this, just scraping , using a belt sander? The customer knows its not going to be perfect but i want to do the best job possible. Right now some of the sides are just a mess. Any advice is appreciated. Thanks!









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## mattpaints82 (Mar 7, 2013)

Would depend on what tools you have at your disposal, if you had a festool rotex or paint shaver id use that. a cheaper option would be a wagner paint eater or an orbital sander with 40 grit. assuming there is no lead paint of course.


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## vincenzocustoms (May 7, 2015)

I appreciate that reply. I did try using an orbital with 60 grit which seemed to help. Would You reccomend a full strip of the siding or just smoothing it out? Thanks 

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## stelzerpaintinginc. (May 9, 2012)

Have you tested for lead?
What year is the home?
Are you RRP Certified?
What's all those white paint-chippy lookin things on the grass?


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## Brian C (Oct 8, 2011)

what a disaster ! Paint chips on the ground and you chewed up the timber siding with the power washer. 

Better for you to hire a professional painting contractor.


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## vincenzocustoms (May 7, 2015)

This i s is post 78 era, no lead. Thankfully. As for the paint chips on the ground, the home owner said that was fine and he got rid of them. When we power washed they were just coming off the house. The siding isnt beat up Brian, i am a professional, was a professional overseas in Iraq and now homeside so go pound sand Brian. I havent been faced with this situation hence why I came here for advice. Im going to continue the orbital sander route as I cant afford a high grade tool at the moment. Thanks again fellas

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## Jmayspaint (Mar 26, 2013)

You could make better time with one of these,

http://www.dewalt.com/tools/woodworking-sanders-random-orbital-sanders-dwe6401ds.aspx

About three times faster than an orbital, and this one costs less than $100. 

Takes a little getting used to how aggressive it is, but this thing will take some paint off quick.


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## vincenzocustoms (May 7, 2015)

I appreciate you posting that, defiantely may look into picking one up oposed to the paint eater.. certain sides of the house arent that bad so i will see how it goes today. 

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## journeymanPainter (Feb 26, 2014)

I wouldn't do a full strip. Sand what you can and prime the entire exterior.


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## D&K Custom (Oct 10, 2014)

After scraping/sanding I would hit it with peel bond or peel stop tripple thick. Perfect job for it. Have been using those products on similar jobs and have been pleased with the final result. 2 coats even...if time and budget permits it.


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## CApainter (Jun 29, 2007)

My paint rep informed me once, that power sanding existing paint can actually degrade the film even further because of the heat generated from the friction of a high speed sander. If you intend to leave portions of the existing paint, understand that it will remain the Achilles Heel of the new coating system.

Any paint remaining, must adhere well and not able to be removed by the mild pressure of a broad knife. The existing paint should be treated with care and not damaged by aggressive sanding. The compromise with leaving existing paint, is that you really can't put a lot of effort into "feathering" with abrasives. This is something the homeowner should understand and agree with before presenting them with the option of a complete removal and sanding to create the defect free surface they might demand.


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## Joshua1304 (Jun 10, 2015)

I like the paint eatter idea. Used them in the past myself with success and project went well.

I would highly encourage you to look into Sherwin-Williams PrimerX or peelbond. Personally I like the swp stuff, apply it at about 15-20 Mills thick then follow it up with 2 coats of a latex top coat that has a good build such as Duration or Emerald but ben-Moore aura is decent. Make sure you get a mill gage from the store to check it.

Seriously ask your store swp manager about PrimeRx or local supplier on Peelbond by XIM. 

If nothing else get it all removed and two coats of a solid stain like superdeck solid finish.


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## Boco (May 18, 2013)

CApainter said:


> My paint rep informed me once, that power sanding existing paint can actually degrade the film even further because of the heat generated from the friction of a high speed sander. If you intend to leave portions of the existing paint, understand that it will remain the Achilles Heel of the new coating system.
> 
> Any paint remaining, must adhere well and not able to be removed by the mild pressure of a broad knife. The existing paint should be treated with care and not damaged by aggressive sanding. The compromise with leaving existing paint, is that you really can't put a lot of effort into "feathering" with abrasives. This is something the homeowner should understand and agree with before presenting them with the option of a complete removal and sanding to create the defect free surface they might demand.


 Whens the last time your paint rep actually sanded or prepped an exterior. Mild pressure with a broad knife my ass. If theres loose paint its got to be removed. When feathering you need to be smarter then the sander.


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## Gough (Nov 24, 2010)

Boco said:


> Whens the last time your paint rep actually sanded or prepped an exterior. Mild pressure with a broad knife my ass. If theres loose paint its got to be removed. When feathering you need to be smarter then the sander.


This has come up before on other threads. The most common place we see paint failure on "feathered" jobs is where the feathering happened. With a thick buildup of paint, it's tough to feather paint without the heat buildup that leads to premature failure.

That's why we don't do it.


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## CApainter (Jun 29, 2007)

Boco said:


> Whens the last time your paint rep actually sanded or prepped an exterior. Mild pressure with a broad knife my ass. If theres loose paint its got to be removed. When feathering you need to be smarter then the sander.


Obviously, complete removal of the existing paint would be the best practice in order to provide the new coating system a platform that won't compromise a manufacturer's performance claims. 

My contention is that for what ever reason, if you can't remove all of the existing paint, that you don't grind the crap out of it in an attempt to simulate an even surface. It will destroy the existing film even further. Especially oil base paint that has exceeded its life cycle through oxidation.

As I understand it, thermoplastics, which most single component paints are, will typically return to their original state, albeit compromised, by the introduction of either heat or solvent. Where as two component thermoset plastics undergo a molecular change during curing that, in many cases, allows better resistance to heat, solvents, and abrasion. In other words, feathering the paint on a car is a lot different then feathering paint on wood siding.

But in any event, I'll add a little more pressure with that broad knife.


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## DrakeB (Jun 6, 2011)

CApainter said:


> As I understand it, thermoplastics, which most single component paints are, will typically return to their original state, albeit compromised, by the introduction of either heat or solvent.


I'm curious about the actual science behind this. When paint dries, a sizable part of the original make-up is "lost" when it evaporates, or irreversibly changed in the case of coalescence (when new bonds are formed as the paint dries). I'd personally suspect that it's simply the heat exciting the molecules and making it more malleable and taking it closer to the melting point of the new substance, rather than actually reverting to its original state.

Citation needed, of course


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## Gough (Nov 24, 2010)

Woodford, extra credit for "coalescence"!


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## DrakeB (Jun 6, 2011)

Gough said:


> Woodford, extra credit for "coalescence"!


I don't think we can count industry specific technical terms on our smart words lists, unfortunately, as much as I'd love to take credit for it :jester:

I can't keep up with you and CApainter anyways; ironically, when I was younger I had a much wider breadth of vocabulary than I do today, but I had to dumb myself down for public consumption to avoid the blank stares.


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## CApainter (Jun 29, 2007)

Woodford said:


> I'm curious about the actual science behind this. When paint dries, a sizable part of the original make-up is "lost" when it evaporates, or irreversibly changed in the case of coalescence (when new bonds are formed as the paint dries). I'd personally suspect that it's simply the heat exciting the molecules and making it more malleable and taking it closer to the melting point of the new substance, rather than actually reverting to its original state.
> 
> Citation needed, of course


You make a good point about coalescence, where the dynamics of solvent (or water) evaporation helps to weave the film structure. However, that structure doesn't undergo an actual chemical conversion as is the case with thermoset epoxies, which create a monolithic structure via chemical conversion.


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## Gough (Nov 24, 2010)

CApainter said:


> You make a good point about coalescence, where the dynamics of solvent (or water) evaporation helps to weave the film structure. However, that structure doesn't undergo an actual chemical conversion as is the case with thermoset epoxies, which create a monolithic structure via chemical conversion.


But some of the processes involved with the later phases of coalescence, like polymer chain entanglement or sufficiently strong to render the process virtually irreversible.

http://wwwcourses.sens.buffalo.edu/ce435/StewardHearnWilkinson2000.pdf


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## Damon T (Nov 22, 2008)

Ok now you guys are just showing off!


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## SemiproJohn (Jul 29, 2013)

Painters are not supposed to be this articulate, correct? This thread is enticing distant memories of chemistry classes. I did not take to chemistry classes well. Dummy it down for me guys. You know, "cheap paint ain't good, good paint ain't cheap." Stuff like that.


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## TJ Paint (Jun 18, 2009)

Consider how the heat gun is employed in product removal... Let's also consider the heat generated from abrasives technology in order to "feather" the profile... What might we conclude?


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## TJ Paint (Jun 18, 2009)

CApainter said:


> You make a good point about coalescence, where the dynamics of solvent (or water) evaporation helps to weave the film structure. However, that structure doesn't undergo an actual chemical conversion as is the case with thermoset epoxies, which create a monolithic structure via chemical conversion.


Water is a solvent! And, just about the most perfect one existing !


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## CApainter (Jun 29, 2007)

TJ Paint said:


> Water is a solvent! And, just about the most perfect one existing !


I know.


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## CApainter (Jun 29, 2007)

Gough said:


> But some of the processes involved with the later phases of coalescence, like polymer chain entanglement or sufficiently strong to render the process virtually irreversible.
> 
> http://wwwcourses.sens.buffalo.edu/ce435/StewardHearnWilkinson2000.pdf


I'm certainly not an expert in the field of chemistry. But, from what I had learned in terms of the types of coatings, is that a thermoset plastic undergoes a completely different process of film development than a thermoplastic.

What I had interpreted as returning to a semblance of an original state, was more or less a loose reference comparing the ability of one to dissolve with solvents from which it was borne, compared to that of the other which its original state had been altered chemically. Essentially, rendering it resistant to dissolvisation by solvents from which _it_ was borne.


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## CApainter (Jun 29, 2007)

Go Warriors :red_indian::


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## Gough (Nov 24, 2010)

CApainter said:


> I'm certainly not an expert in the field of chemistry. But, from what I had learned in terms of the types of coatings, is that a thermoset plastic undergoes a completely different process of film development than a thermoplastic.
> 
> What I had interpreted as returning to a semblance of an original state, was more or less a loose reference comparing the ability of one to dissolve with solvents from which it was borne, compared to that of the other which its original state had been altered chemically. Essentially, rendering it resistant to dissolvisation by solvents from which _it_ was borne.


This post was worth it for this word alone!:thumbup:


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## daArch (Mar 15, 2008)

effete elitist esoteric erudite exhibitionists ! ! !


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## CApainter (Jun 29, 2007)

Gough said:


> This post was worth it for this word alone!:thumbup:


, but then I screwed up on the repost. 

But the point I was making is valid.


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## CApainter (Jun 29, 2007)

daArch said:


> effete elitist esoteric erudite exhibitionists ! ! !


 @daArch. Instigator.


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## daArch (Mar 15, 2008)

CApainter said:


> @daArch. Instigator.


 at least do me the honor of calling me an

insufferable ineffective intrusive instigator :thumbsup:


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## DrakeB (Jun 6, 2011)

CApainter said:


> You make a good point about coalescence, where the dynamics of solvent (or water) evaporation helps to weave the film structure. However, that structure doesn't undergo an actual chemical conversion as is the case with thermoset epoxies, which create a monolithic structure via chemical conversion.


Actually, I believe they do have a chemical structural change. They form something known as colloidal crystals which, while I'm not certain whether any electrons are exchanged or shared, does constitute a deformation of the polymers, which I would still consider a structure change and a chemical conversion (since it's not an actual technical term). The properties and structure of the film are different than the properties and structure of the original molecules in their emulsion, and that deformation of polymers isn't one that can be reversed as far as my research has shown.

Citation: http://wwwcourses.sens.buffalo.edu/ce435/StewardHearnWilkinson2000.pdf


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## CApainter (Jun 29, 2007)

Woodford said:


> Actually, I believe they do have a chemical structural change. They form something known as colloidal crystals which, while I'm not certain whether any electrons are exchanged or shared, does constitute a deformation of the polymers, which I would still consider a structure change and a chemical conversion (since it's not an actual technical term). The properties and structure of the film are different than the properties and structure of the original molecules in their emulsion, and that deformation of polymers isn't one that can be reversed as far as my research has shown.
> 
> Citation: http://wwwcourses.sens.buffalo.edu/ce435/StewardHearnWilkinson2000.pdf


I won't pretend to be as knowledgeable as the rest of you, but, there is a difference between a conversion coating and a non conversion coating. Single component paints are non conversion (aside from oil/alkyds that cure by oxidation). Two component paints are conversion. Whether "conversion" has anything to do with the difference in chemical reaction of the two, I'll leave to the rest of you. 

Bottom line, once cured, epoxies are different than single component paints, and Thermo plastics are different then thermoset plastics. For example, you can heat and reweld PVC because it is a thermoplastic, but you can't with thermosets.


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## Gough (Nov 24, 2010)

Woodford and CA'

Where did everybody else go?


((crickets))


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## CApainter (Jun 29, 2007)

Gough said:


> Woodford and CA'
> 
> Where did everybody else go?
> 
> ...


I think you guys determined there's no difference in paints. So we're moving on.


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## DrakeB (Jun 6, 2011)

CApainter said:


> I won't pretend to be as knowledgeable as the rest of you, but, there is a difference between a conversion coating and a non conversion coating. Single component paints are non conversion (aside from oil/alkyds that cure by oxidation). Two component paints are conversion. Whether "conversion" has anything to do with the difference in chemical reaction of the two, I'll leave to the rest of you.
> 
> Bottom line, once cured, epoxies are different than single component paints, and Thermo plastics are different then thermoset plastics. For example, you can heat and reweld PVC because it is a thermoplastic, but you can't with thermosets.


Oh yes, oxidation functionally is very, very difference from coalescence and evaporation (though both do occur to some extent in paints that cure by oxidation). When oil based (or most other not latex aka "emulsion" paints) dry they form new crosslink bonds, which are true chemical bonds involving either covalent or ionic bonds (sharing or exchanging electrons, in simple terms). This is more than a structural change in the layout of the atoms; in emulsion paints the strength comes from an organized, crystalline layout. In oxidative process paints, the strength comes from the molecules actually bonding together. The end result of both are fairly functionally similar, though structurally they are quite dissimilar.


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## Wildbill7145 (Apr 30, 2014)

Are you guys cutting and pasting this stuff from somewhere?


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## DrakeB (Jun 6, 2011)

Wildbill7145 said:


> Are you guys cutting and pasting this stuff from somewhere?


If you Google my paragraphs you'll find out


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## CApainter (Jun 29, 2007)

Wildbill7145 said:


> Are you guys cutting and pasting this stuff from somewhere?


I'm sure the others already know this stuff. I'm just repeating what I learned on a very basic level. And that is, there are two types of plastics. Thermo and thermoset. These can be used to describe paint films. 

Also, there are two types of processes occuring during paint film formation. One is a conversion and the other is a non conversion. Epoxies are in the conversion catagory. Conversion coatings are typically more resistant to solvents then non conversion coatings. 

It's been awhile since I took the SSPC coatings course, but that's what I learned. And none of my posts have been copied and pasted. I haven't even visited wikipedia.


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## Wildbill7145 (Apr 30, 2014)

CApainter said:


> I'm sure the others already know this stuff. I'm just repeating what I learned on a very basic level. And that is, there are two types of plastics. Thermo and thermoset. These can be used to describe paint films.
> 
> Also, there are two types of processes occuring during paint film formation. One is a conversion and the other is a non conversion. Epoxies are in the conversion catagory. Conversion coatings are typically more resistant to solvents then non conversion coatings.
> 
> It's been awhile since I took the SSPC coatings course, but that's what I learned. And none of my posts have been copied and pasted. I haven't even visited wikipedia.


I hope you guys know I was just kidding around. Basically saying everything I was reading was slightly beyond me.

It's been a long time since I took grade 13 chemistry, even the second time I took it.


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## Gough (Nov 24, 2010)

Wildbill7145 said:


> I hope you guys know I was just kidding around. Basically saying everything I was reading was slightly beyond me.
> 
> It's been a long time since I took grade 13 chemistry, even the second time I took it.


You might want to explain the whole Grade 13 part, especially for our members unfamiliar with the former educational system in ON.


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## CApainter (Jun 29, 2007)

Wildbill7145 said:


> I hope you guys know I was just kidding around. Basically saying everything I was reading was slightly beyond me.
> 
> It's been a long time since I took grade 13 chemistry, even the second time I took it.


I think what happened was a basic point developed into a search for an absolute truth on the matter. And as I stated before, I am far from being competent as a coating expert, in terms of chemical cross linking, and other processes that help form a paint film. That's why I try to be careful not to plagiarize the internet to present myself like I'm an expert.

I was just trying to point out the difference in thermo plastics verses thermoset plastics and how one might be affected more by the heat generated from a high speed sander as opposed to the other. Especially, since a lot of exterior house paints are considered a form of thermo plastic.

But I can accept that things have changed and there are no diferences between the two. It's all an illusion anyways.


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## Wildbill7145 (Apr 30, 2014)

Gough said:


> You might want to explain the whole Grade 13 part, especially for our members unfamiliar with the former educational system in ON.


Used to have to go to grade 13 in high school if you had any intention whatsoever of being able to go to university. Then they changed it to OAC (Ontario Academic Course), but I think they've changed it again since then. 

My nephew tried to explain it to me a couple of years ago when he was graduating, but seeing as how he was still a teenager I was barely listening.


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## Gough (Nov 24, 2010)

Wildbill7145 said:


> Used to have to go to grade 13 in high school if you had any intention whatsoever of being able to go to university. Then they changed it to OAC (Ontario Academic Course), but I think they've changed it again since then.
> 
> My nephew tried to explain it to me a couple of years ago when he was graduating, but seeing as how he was still a teenager I was barely listening.


IIRC, they dropped the OAC around 2003, AKA the year of the "double cohort". Two years of students graduated secondary school that year, overloading the post-secondary system.


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## Wildbill7145 (Apr 30, 2014)

Gough said:


> IIRC, they dropped the OAC around 2003, AKA the year of the "double cohort". Two years of students graduated secondary school that year, overloading the post-secondary system.


Can't imagine what your required high school average had to be that year to get in to university. Wow, must have gone through the roof.


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## Gough (Nov 24, 2010)

Wildbill7145 said:


> Can't imagine what your required high school average had to be that year to get in to university. Wow, must have gone through the roof.


I guess there was a Double Cohort Echo in 2007, when they all graduated university and started looking for work.


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## DrakeB (Jun 6, 2011)

CApainter said:


> I think what happened was a basic point developed into a search for an absolute truth on the matter. And as I stated before, I am far from being competent as a coating expert, in terms of chemical cross linking, and other processes that help form a paint film. That's why I try to be careful not to plagiarize the internet to present myself like I'm an expert.
> 
> I was just trying to point out the difference in thermo plastics verses thermoset plastics and how one might be affected more by the heat generated from a high speed sander as opposed to the other. Especially, since a lot of exterior house paints are considered a form of thermo plastic.
> 
> But I can accept that things have changed and there are no diferences between the two. It's all an illusion anyways.


I hope you don't think I'm disagreeing that there's a difference between the two, as there surely is. I'm just curious about the science behind it. I hope you don't think I'm trying to present myself as an expert or plagiarizing, either; I'll certainly admit to having looked for some scholarly articles to back up my prior knowledge on the subject, but I try not to discuss anything I don't have a fair working understanding of. At any rate, I'll let it be now. It wouldn't be the first time my curiosity'd gotten the better of me.


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## CApainter (Jun 29, 2007)

Woodford said:


> I hope you don't think I'm disagreeing that there's a difference between the two, as there surely is. I'm just curious about the science behind it. I hope you don't think I'm trying to present myself as an expert or plagiarizing, either; I'll certainly admit to having looked for some scholarly articles to back up my prior knowledge on the subject, but I try not to discuss anything I don't have a fair working understanding of. At any rate, I'll let it be now. It wouldn't be the first time my curiosity'd gotten the better of me.


I'm actually pretty comfortable with my basic knowledge of thermo and thermo set plastics, along with the process associated with conversion and non conversion coatings. I know enough to have kept me out of trouble over the many years of applying both.


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## SemiproJohn (Jul 29, 2013)

Gough said:


> This post was worth it for this word alone!:thumbup:


Dissolvisation: The process by which an Alka Seltzer tablet eventually disappears when placed in a glass of water. :whistling2:


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## SemiproJohn (Jul 29, 2013)

Some of you guys never fail to impress me while enlightening me. I feel like I should be paying tuition.

I must admit reading things like ionic and covalent bonds gave me unhappy memories. I'll be impressed when you can incorporate Avogadro's number into this discussion in a meaningful way. And don't neglect the periodic table of the elements. :jester:


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## DrakeB (Jun 6, 2011)

CApainter said:


> I'm actually pretty comfortable with my basic knowledge of thermo and thermo set plastics, along with the process associated with conversion and non conversion coatings. I know enough to have kept me out of trouble over the many years of applying both.


I hope you don't think I was casting any doubt on that, either. You're clearly one of the most educated people on this forum, and I'm just a new comer to the trade after all. If my responses to you stepped on your toes, I apologize. It's not often I get the chance to discuss topics this interesting (yes, I'm serious) with other intelligent people.


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## chrisn (Jul 15, 2007)

Woodford said:


> I hope you don't think I was casting any doubt on that, either. You're clearly one of the most educated people on this forum, and I'm just a new comer to the trade after all. If my responses to you stepped on your toes, I apologize. It's not often I get the chance to discuss topics this interesting (yes, I'm serious) with other intelligent people.


HERE??:laughing::laughing::laughing:


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## CApainter (Jun 29, 2007)

Woodford said:


> I hope you don't think I was casting any doubt on that, either. You're clearly one of the most educated people on this forum, and I'm just a new comer to the trade after all. If my responses to you stepped on your toes, I apologize. It's not often I get the chance to discuss topics this interesting (yes, I'm serious) with other intelligent people.


No problem. It's just like the business talk that takes place here. As a member who likes to participate in discussions, I have a limited knowledge before my contributions become useless opinions. So I absolutely respect and enjoy your knowledge as a paint supplier and contributing member. And, I respect Gough's contributions as Galactic Lord of Infinite knowledge and How it Applies to Law/ Internet Librarian.


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## SemiproJohn (Jul 29, 2013)

CApainter said:


> No problem. It's just like the business talk that takes place here. As a member who likes to participate in discussions, I have a limited knowledge before my contributions become useless opinions. So* I absolutely respect and enjoy your knowledge as a paint supplier and contributing member. And, I respect Gough's contributions as Galactic Lord of Infinite knowledge and How it Applies to Law/ Internet Librarian.*




As do I CA Painter, as do I.


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## Gough (Nov 24, 2010)

:blush::blush:

Believe me, I wish I could remember the more important things, like where I left my keys.


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## daArch (Mar 15, 2008)

Ya no, it's peeps lik u woo give payntrs bad reps.


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## I paint paint (May 4, 2014)

Poor, poor Vinnie. 5 posts in his pocket, courage up to start a thread, and this is where it leads. How many replies in did he just go back to blasting away with his water cannon?

And who's more pissed with their job this week, our man Vinnie or newbie AppleJack?

Me, I'm just glad I won't be hanging off an extension ladder this weekend like I was all week.


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## thinkpainting/nick (Dec 25, 2012)

Jmayspaint said:


> You could make better time with one of these,
> 
> http://www.dewalt.com/tools/woodworking-sanders-random-orbital-sanders-dwe6401ds.aspx
> 
> ...


I know this old post but we still use my Makita random orbitals both about 25 yrs old still going strong. The paint store I do business with carry a wide variety of supplies still for this tool. Have never tried the dewalt but thanks for the link.


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## silverhw (Jul 3, 2015)

I think my IQ just raised a couple of points after reading this thread. Thanks guys!:notworthy:


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