# spray vs spray and back brush



## gstrick (Aug 1, 2011)

I know im new to the game so please excuse the novice question

I have always backbrushed my exterior work (primarily stain) and am wondering if you can achieve the same quality job spraying laytex paint without backbrushing. I allways went with the idea that a spray job was a lower quality job in terms of longevity.


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## NEPS.US (Feb 6, 2008)

Spraying can be used on various substrates to achieve a wide variety of results base off of the product and substrate. In some cases back brushing is doing no more than pushing product around on the surface and in others it is helping to work the product into the grains of the wood. In most case spraying is a production method to getting the product to the substrate and how the operator applies it will dictate how the product will perform on the substrate.


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## gstrick (Aug 1, 2011)

Thanks for the answer. As i assumed, it is not a simple yes or no. Would you backbrush a true-value weather-all (HO bought) on pre-primed clapboards or just spray.


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## NEPS.US (Feb 6, 2008)

gstrick said:


> Thanks for the answer. As i assumed, it is not a simple yes or no. Would you backbrush a true-value weather-all (HO bought) on pre-primed clapboards or just spray.


First - I wouldn't be in a position to do anything with a True Value paint or a paint bought by a HO. 

New or old claps? New cedar claps I would spray and back brush one coat of a oil base primer making sure to seal all nail heads punctured through the claps. Spray and backbrush the first coat of paint and only spray the final coat. 

But of course your a professional and already know this.


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## jack pauhl (Nov 10, 2008)

gstrick said:


> I allways went with the idea that a spray job was a lower quality job in terms of longevity.


I hope not.


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## BreatheEasyHP (Apr 24, 2011)

gstrick said:


> I allways went with the idea that a spray job was a lower quality job in terms of longevity.


Reasons to backroll/backbrush:

1) Work the material into the substrate. Paint will bridge cracks, divits, pores, etc. This paint, as the reasoning goes, is likely to fail. 
2) Achieve an even finish if you can't get an even finish without working the material


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## 4ThGeneration (Apr 17, 2007)

always depends on the surface and the condition. 

Example:
aluminum is always spray what can be sprayed and minimal brush or roller used.

T-111 is sprayed, backrolled and when second coat comes around it will be sprayed the final time.

stucco is sprayed and back rolled with final coat being sprayed on.

It all depends.


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## bikerboy (Sep 16, 2007)

Do whatever the can says and cover your butt.

From what I was taught, back brushing releases surface tension of the applied product which allows it to better penetrate the surface. 

Like NEPS said, you only need to do it on the first coat.


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## aaron61 (Apr 29, 2007)

I allways went with the idea that a spray job was a lower quality job in terms of longevity.

This simply is not true.Some of our "potential" older customers believe this as well. It's just simply a quicker way of getting the product to the surface you are painting.And in my opinion better in most cases.Human nature is to be a little bit lazy.So you tend to make that loaded brush or roller go a little bit farther between dips.Spraying (properly) will give you consistent millage and usually is faster,not always.Back brushing or rolling will work it in to porous surfaces.On smooth surfaces it is not necessary. IMHO
I have never seen a manufacturers statement that brushing & rolling will make their product perform better.


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## paint2ski (Jan 20, 2011)

Just my 2 cents in case anyone hits this thread again.. I always backbrush both coats on exterior walls and backroll interior walls. Both make for easier touch ups in the end or down the road and on exteriors I always will get a sheen funk from certain angles if I just spray. From the road it looks fine but if I'm gettin paid I like it to look perfect so backbrush enough on the 2nd coat to smooth it off. 

Also If u spray too much on how you gonna even it off without backbrushing. That's what I do anyway. But have had good results with hardiboard just spraying out the second coat and usually spray out the second coat on soffits and less noticable areas. But walls gotta have those looking good or from certain angles it's a bummer....


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## Custom Brush Co. (Jan 26, 2011)

paint2ski said:


> Just my 2 cents in case anyone hits this thread again.. I always backbrush both coats on exterior walls and backroll interior walls. Both make for easier touch ups in the end or down the road and on exteriors I always will get a sheen funk from certain angles if I just spray. From the road it looks fine but if I'm gettin paid I like it to look perfect so backbrush enough on the 2nd coat to smooth it off.
> 
> Also If u spray too much on how you gonna even it off without backbrushing. That's what I do anyway. But have had good results with hardiboard just spraying out the second coat and usually spray out the second coat on soffits and less noticable areas. But walls gotta have those looking good or from certain angles it's a bummer....


SPRAYING right takes time & awareness! If you have to back appy 2nd coat seems you may be new to spraying.

Here is the skinny... Create a non-porus substrate on the first coat by back brushing/rolling. Then spray only the 2nd. You can always get the paint on thicker this way. back applying the 2nd coat is a waste of time & takes paint off you could be leaving. Touch ups are hardest when spray only smooth non-porus substrates like hardi plank. They can flash. Why it's good to back apply first. Get the paint in the surface pours.


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## Gough (Nov 24, 2010)

bikerboy said:


> Do whatever the can says and cover your butt.
> 
> From what I was taught, back brushing releases surface tension of the applied product which allows it to better penetrate the surface.
> 
> Like NEPS said, you only need to do it on the first coat.


From what I've read in the technical coatings literature, the opposite is true for paint, that back-brushing a spray coat stresses the interface between the newly applied coat and the substrate, leading to premature failure. That was backed up with some tests with some carefully prepared samples of the different treatments, but all finished with the same film thickness. Their conclusion was that, all other things being equal, a spray coat of paint will last longer.

The problem being that all things are rarely equal. A lot of run-and-gun types skimp on both prep and material, giving conscientious spray applicators a bad name.


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## Damon T (Nov 22, 2008)

Gough said:


> From what I've read in the technical coatings literature, the opposite is true for paint, that back-brushing a spray coat stresses the interface between the newly applied coat and the substrate, leading to premature failure. That was backed up with some tests with some carefully prepared samples of the different treatments, but all finished with the same film thickness. Their conclusion was that, all other things being equal, a spray coat of paint will last longer.
> 
> The problem being that all things are rarely equal. A lot of run-and-gun types skimp on both prep and material, giving conscientious spray applicators a bad name.


Very interesting ! Do you have any links to those tests? 

I sprayed one coat of Duration on my rough sawn cedar house several years ago, though I did several coats on the upper deck side which gets a lot of sun. Mostly because I didn't need a ladder and it was so easy. Otherwise though, spray only and man it looks perfect still. I have mostly back rolled first coat and sprayed second on rough sawn, but for my own house I just wanted to get it done. Have recently done a few jobs just spray two coats and they look just dandy. While I will never say that back brushing or rolling is bad, I'm not prepared to say that just spraying is bad either depending on the situation.


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## Gough (Nov 24, 2010)

Damon T said:


> Very interesting ! Do you have any links to those tests?
> 
> I sprayed one coat of Duration on my rough sawn cedar house several years ago, though I did several coats on the upper deck side which gets a lot of sun. Mostly because I didn't need a ladder and it was so easy. Otherwise though, spray only and man it looks perfect still. I have mostly back rolled first coat and sprayed second on rough sawn, but for my own house I just wanted to get it done. Have recently done a few jobs just spray two coats and they look just dandy. While I will never say that back brushing or rolling is bad, I'm not prepared to say that just spraying is bad either depending on the situation.


Damon, I'm sorry, I don't. The sources were actual books/periodicals from the library of the local university. Pretty old school. eh?


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