# how low can you go?



## miket (Sep 16, 2009)

How low of psi can you go when priming drywall?

If you
A smooth the low psi finish out by backrolling
B oversize the tip orifice to keep reasonable production speed.


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## TJ Paint (Jun 18, 2009)

I don't know. Tell us.


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## miket (Sep 16, 2009)

I don't know, and i don't have a prime job for a while. 

Why? Do some people here make a habit of asking questions that they already know the answers to, too show off?:yes:


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## TJ Paint (Jun 18, 2009)

miket said:


> I don't know, and i don't have a prime job for a while.
> 
> Why? Do some people here make a habit of asking questions that they already know the answers to, too show off?:yes:


I just figured you could test it out and tell us. Why do you want to know? Less overspray? Why do you want to know if you don't have a job pertaining to your question? 

Why dammit?


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## benthepainter (Jun 17, 2011)

TJ Paint said:


> I just figured you could test it out and tell us. Why do you want to know? Less overspray? Why do you want to know if you don't have a job pertaining to your question?
> 
> Why dammit?



Every time i jump on PT lately 

Its like i have to fill out a survey 

Question A
Question B

Rate out of 10 : )

Can we get steve Back so he can post some random **** 

And Bring Dad back to lock threads down and debate with other members in PZ


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## Wolfgang (Nov 16, 2008)

Ben, here's a hint: You don't have to participate in every thread. As far as a few members not being active on PT of late, I'm sure they have their reasons. Not the first time, won't be the last.

Post some pics of your lunch set-ups and you'll feel better.


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## benthepainter (Jun 17, 2011)

Wolfgang said:


> Ben, here's a hint: You don't have to participate in every thread. As far as a few members not being active on PT of late, I'm sure they have their reasons. Not the first time, won't be the last.
> 
> Post some pics of your lunch set-ups and you'll feel better.


Gday Wolf 

I dont need a hint : ) 

Just having some fun 

I dont post in every thread i couldnt care if anyone else did either 

i just honestly enjoyed Bills posts especially the way he would be in every post he is or was a great Member loved reading his replies in the PZ 

Hope he returns : )


In regards to Lunch setup Pics lol im not one to recycle old pics unless i have something new to post I'm done

If i bake a cake at work i would find that fairly impressive might share that one 

Other than that i will just carry on painting and cooking : ) 

Actualy last pic : )

at work yesterday cooking some lunch cracked a double yoke i was very excited double yoker i kid you not same time ipad ****ing falls of my lunch chair and i cracked my screen ****

Your right i do feel better posting up a pic of my lunch setup : )
Thanks


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## Bender (Aug 10, 2008)

benthepainter said:


> Every time i jump on PT lately
> 
> Its like i have to fill out a survey
> 
> ...


Maybe you are the new Steve Richards?


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## Bender (Aug 10, 2008)

miket said:


> How low of psi can you go when priming drywall?
> 
> If you
> A smooth the low psi finish out by backrolling
> B oversize the tip orifice to keep reasonable production speed.


Heck, if you are back rolling I bet you could run down near 1000psi, maybe even 7-800. At that point its just a faster delivery system, nothing more.


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## mudbone (Dec 26, 2011)

miket said:


> How low of psi can you go when priming drywall?
> 
> If you
> A smooth the low psi finish out by backrolling
> B oversize the tip orifice to keep reasonable production speed.


 I would milk it miket!:whistling2:


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## Oden (Feb 8, 2012)

all the spraying I do and the PSI stuff goes right past me. I used I'm sure by now 100 different pumps and never had or never looked for a PSI gauge. I crank it up or down to where I want it not unlike a garden hose.


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## slinger58 (Feb 11, 2013)

benthepainter said:


> Every time i jump on PT lately
> 
> Its like i have to fill out a survey
> 
> ...


Hey Ben, the old saying is "the only constant in this world is change".
I'm betting SR and DaArch will come back to PT at some point. I hope so, but if they don't, I wish them both well. But the world and PT will carry on. :yes:


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## Jmayspaint (Mar 26, 2013)

slinger58 said:


> the old saying is "the only constant in this world is change".


 
Words of wisdom for sure..


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## Jmayspaint (Mar 26, 2013)

[QUOTE="benthepainter") just honestly enjoyed Bills posts especially the way he would be in every post he is or was a great Member loved reading his replies in the PZ
[/QUOTE]

Has there even been a PZ post since he's been absent?.... Dead at the moment anyway. 

I miss that ReNtApAinTeR guy, he cracked me up on a regular basis. 

Thanks for the foodie posts Ben, always entertaining. :thumbsup:


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## slinger58 (Feb 11, 2013)

Oden said:


> all the spraying I do and the PSI stuff goes right past me. I used I'm sure by now 100 different pumps and never had or never looked for a PSI gauge. I crank it up or down to where I want it not unlike a garden hose.


Same here. Depends on tip size, type of material, how worn the tip is, what type of surface I'm spraying, and last but not least, how I am feeling. :jester:


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## TJ Paint (Jun 18, 2009)

Jmayspaint said:


> Words of wisdom for sure..


I think this nugget of wisdom is best tempered by the saying: "There's nothing new under the sun" -King Solomon.


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## slinger58 (Feb 11, 2013)

And this thread is about what .........PSI ? On an airless?
This is one crazy place. :thumbsup:


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## TJ Paint (Jun 18, 2009)

slinger58 said:


> And this thread is about what .........PSI ? On an airless?
> This is one crazy place. :thumbsup:


No man. Its about thinking existentially.


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## miket (Sep 16, 2009)

Jmayspaint said:


> Has there even been a PZ post since he's been absent?.... Dead at the moment anyway.
> 
> I miss that ReNtApAinTeR guy, he cracked me up on a regular basis.
> 
> Thanks for the foodie posts Ben, always entertaining. :thumbsup:



Those people probably left because of 80% of the posts being useless like in this thread.


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## Bender (Aug 10, 2008)

Phuck it dude, lets bowl.


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## miket (Sep 16, 2009)

Not sure what bowling has anything to do with it but since your the only other person here who knows what psi means i'll ask this directly to you.

Is there a point where lowering the pressure more doesn't increase transfer efficiency?

Bounceback, overspray, and tip wear are just wasted money after all.


Are there sprayers that increase max gpm at lower psi? Obviously i mean low spraying psi and not very low Fastflush or rapidlcean psi. After all HP is proportional to psi x gpm.


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## TJ Paint (Jun 18, 2009)

miket said:


> Not sure what bowling has anything to do with it but since your the only other person here who knows what psi means i'll ask this directly to you.
> 
> Is there a point where lowering the pressure more doesn't increase transfer efficiency?
> 
> ...


Its been already mentioned but maybe you missed it. It depends on several factors. Material being sprayed, tip size, substrate, environmental factors, how many people working together. 

You should be able to reduce psi and increase transfer efficiency some as long as you're backrolling. You will get to a point where you reach diminishing returns because more labor will be required to backroll smooth and even to seal properly. 

If you are not wanting to waste any paint, just leave the sprayer at home and roll it all. If your labor is worth less than product, this could be a better option for you. 

A real-life example: I was priming ext siding and backrolling one full coat. I turned my psi down as low as I could to reduce overspray. Not because I was concerned about wasting but was about overspray on surrounding objects. I have no idea what the psi was. I just know it was at a point where it atomized enough so it went on even and I could backroll it decent but it wasn't so slow that it was a waste of time. I held my gun a tad closer to the siding as well to compensate for lower psi. Appox 6 inches distance, which would be another factor also.

You can theorize all night and day but its worthless if you don't apply it to something real.


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## miket (Sep 16, 2009)

TJ Paint said:


> Its been already mentioned but maybe you missed it. It depends on several factors. Material being sprayed, tip size, substrate, environmental factors, how many people working together.
> 
> but it wasn't so slow that it was a wasye of time.


I agree that the pressure will change with the material being sprayed.

Why would lower pressure slow the person spraying down at all if you also increased the tip size ?
Shoudlnt speed stay the same? Why would it change how many people are working with you if your going the same speed?

Which tip sizes do you use more pressure with and which do you less? Which substrates do you use more or less pressure on?


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## TJ Paint (Jun 18, 2009)

miket said:


> I agree that the pressure will change with the material being sprayed.
> 
> Why would lower pressure slow the person spraying down at all if you also increased the tip size ?
> Shoudlnt speed stay the same? Why would it change how many people are working with you if your going the same speed?
> ...


I'm done. Get a project and find out for yourself. Until you actually got a job and try things out I'm out of time.


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## slinger58 (Feb 11, 2013)

TJ Paint said:


> I'm done. Get a project and find out for yourself.


LOL. Well, you tried.:whistling2:


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## Jmayspaint (Mar 26, 2013)

For drywall specifically, I like to use high pressure (2,000). This does create a lot of overspray, and I can see the advantage to what you are theorizing with lower pressures and bigger tip sizes. I use tips from 515 up to 619 for drywall, I don't find that the bigger tips really allow me to reduce pressure much without compromising the evenness of the fan pattern. 

And I do get the idea that that doesn't matter as much with back rolling... But it still matters some. 
At high pressure, with an even fan pattern, I can get away with very little back rolling. Essentially one downstroke with the roller. 
Sometimes when shielding, I will turn the pressure down to make shielding easier, which compromises the fan to an extent, and just back roll it out smooth. But doing this require more vigorous back rolling. 

I get the best results when I can get an even coat on as quickly as possible, and with as little tooling as possible. Especially with enamel. 

For me, having to back roll more to even out an uneven spray job,would not be worth the Benefits of lower pressure in most cases. 

Here is some satin enamel sprayed at high pressure with one down stroke back roll.


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## MikeCalifornia (Aug 26, 2012)

Jmayspaint said:


> For drywall specifically, I like to use high pressure (2,000). This does create a lot of overspray, and I can see the advantage to what you are theorizing with lower pressures and bigger tip sizes. I use tips from 515 up to 619 for drywall, I don't find that the bigger tips really allow me to reduce pressure much without compromising the evenness of the fan pattern.
> 
> And I do get the idea that that doesn't matter as much with back rolling... But it still matters some.
> At high pressure, with an even fan pattern, I can get away with very little back rolling. Essentially one downstroke with the roller.
> ...


For airless 2000psi is very low, probably the lowest that paint will effectively atomize. 3200psi is the max on most smaller pumps and will create a ton of overspray. For the OP, all materials will need a unique psi to get a fan with no tails. Psi for the same material will vary depending on how much it was thinned and what tip is being used.

You should just go to Graco or Titan website and read a little about airless machines. You should learn more from that than asking it here.


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## miket (Sep 16, 2009)

Jmayspaint said:


> For drywall specifically, I like to use high pressure (2,000). This does create a lot of overspray, and I can see the advantage to what you are theorizing with lower pressures and bigger tip sizes. I use tips from 515 up to 619 for drywall, I don't find that the bigger tips really allow me to reduce pressure much without compromising the evenness of the fan pattern.
> 
> And I do get the idea that that doesn't matter as much with back rolling... But it still matters some.
> At high pressure, with an even fan pattern, I can get away with very little back rolling. Essentially one downstroke with the roller.
> ...


I should haven mentioned in the original post how low can you go without having to double or triple backroll. I though it was obvious that if you make more work you've gone too far.

By big tip i mean larger orifice for the fan width, 619 is about the same ratio as a 517 so not big. 515 is smaller ratio. Unless you mean you've tried big tips and stuck with the normal ones?

My current machine doesnt have a digital readout but the one im getting soon will, so i'll know the psi.


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## TJ Paint (Jun 18, 2009)

The bigger the tip the higher psi needed for atomization, all things constant.

You're complicating the sht out of this.


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## miket (Sep 16, 2009)

MikeCalifornia said:


> For airless 2000psi is very low, probably the lowest that paint will effectively atomize. 3200psi is the max on most smaller pumps and will create a ton of overspray. For the OP, all materials will need a unique psi to get a fan with no tails. Psi for the same material will vary depending on how much it was thinned and what tip is being used.
> 
> You should just go to Graco or Titan website and read a little about airless machines. You should learn more from that than asking it here.


Yeah i didnt thing 2000 would be considered very high. Maybe low maybe medium in this context On the other hand with backrolling theres an amount of orange peel and maybe very slight tails would not show after the roller.

Graco and titan websites list psi ranges for different material but not for different tips sizes with those materials.

I only thin out paint when brushing to get it to flow, or when priming bare plaster and then i thin it a whole lot to get it to absorb in better.


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## Jmayspaint (Mar 26, 2013)

miket said:


> Yeah i didnt thing 2000 would be considered very high
> 
> Graco and titan websites list psi ranges for different material but not for different tips sizes with those materials.
















That info is usually on the TDS of the product. 

2,000 is not low going by recommended psi for several interior paints. 

I'm probably spraying higher than that most of the time. My machine maxes out at 3k, and I can usually crank it down some (3/4 turn maybe) without getting tails.


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## Oden (Feb 8, 2012)

I'm priming/finishing drywall right now. I'm using a slow stroker (my term for the biggest style pump-more than that I don't know or care to) and a blowed out .517. pressure is full on and a tick back. I'm blasting paint on the walls. I adjust how heavy I'm spraying a bit so I can Backroll. The first couple walls are a bit light, then heavier and heavier so I got time to Backroll that run. I'm working by myself. Saving on material isn't important to me my time is.


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## slinger58 (Feb 11, 2013)

Oden said:


> I'm priming/finishing drywall right now. I'm using a slow stroker (my term for the biggest style pump-more than that I don't know or care to) and a blowed out .517. pressure is full on and a tick back. I'm blasting paint on the walls. I adjust how heavy I'm spraying a bit so I can Backroll. The first couple walls are a bit light, then heavier and heavier so I got time to Backroll that run. I'm working by myself. Saving on material isn't important to me my time is.


Oden, I just ordered a needle kit and some check valves for my HVLP from 
spraymall. Thanks again for the tip.
Gotta say that buying parts online is easier on my feet. I may start calling it "recliner shopping". :thumbsup:


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## slinger58 (Feb 11, 2013)

Oops, wrong thread. 
ok, I'm gonna be spraying at about 8.5 psi. ( Whatever psi means.)
How's that? :whistling2:


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## miket (Sep 16, 2009)

TJ Paint said:


> The bigger the tip the higher psi needed for atomization, all things constant.
> 
> You're complicating the sht out of this.


In the graco manual on airless spraying techniques one of the remedies for tailing is to 'Change to larger orifice size, same pressure' The other remedy is the obvious 'Increase fluid pressure.'

But in the graco manual on atomization they say that larger orifice creates larger droplets at the same pressure.

Confusing!


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## miket (Sep 16, 2009)

slinger58 said:


> Oops, wrong thread.
> ok, I'm gonna be spraying at about 8.5 psi. ( Whatever psi means.)
> How's that? :whistling2:


Sure its 8.5? This might be a more accurate way for you to measure your spray.

http://www.researchgate.net/publica...er_Urine_Pressure_Measurement_ASIC_and_System

:whistling2::whistling2:


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## TJ Paint (Jun 18, 2009)

miket said:


> Sure its 8.5? This might be a more accurate way for you to measure.
> 
> http://www.researchgate.net/publication/3481300_A_Mini-Invasive_Long-Term_Bladder_Urine_Pressure_Measurement_ASIC_and_System
> 
> :whistling2:


Hey miket, where are you from?


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## TJ Paint (Jun 18, 2009)

miket said:


> In the graco manual on airless spraying techniques one of the remedies for tailing is to 'Change to larger orifice size, same pressure' The other remedy is the obvious 'Increase fluid pressure.'
> 
> But in the graco manual on atomization they say that larger orifice creates larger droplets at the same pressure.
> 
> Confusing!


I'm done. But good luck on your next project... whenever that is. if at that point you have a specific question, ill be there bro. All this vague hypothetical stuff is lame.


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## slinger58 (Feb 11, 2013)

miket said:


> Sure its 8.5? This might be a more accurate way for you to measure.
> 
> http://www.researchgate.net/publica...er_Urine_Pressure_Measurement_ASIC_and_System
> 
> :whistling2:


Interesting. But whether I'm taking a leak or spraying paint, I'm just gonna play with it until it does right and not worry too much about the actual psi. :jester:


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## miket (Sep 16, 2009)

TJ Paint said:


> I'm done. But good luck on your next project... whenever that is. if at that point you have a specific question, ill be there bro. All this vague hypothetical stuff is lame.


The graco spraying guide tells you to increase the orrifice size when you get tailing. That's vague and hypothetical?


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## Bender (Aug 10, 2008)

MikeCalifornia said:


> For airless 2000psi is very low, probably the lowest that paint will effectively atomize.


I disagree. 2K is a bit high in my opinion and I don't think atomization is relevant for backrolling.


Oden said:


> Saving on material isn't important to me my time is.


I disagree with this as well. Back in the day when paint was $12.00 a gallon and labor was $20.00+ an hour, material costs were unimportant, labor was. But now its not uncommon for a man to put up several times his wage in materials a day.


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## Bender (Aug 10, 2008)

miket said:


> My current machine doesnt have a digital readout but the one im getting soon will, so i'll know the psi.


You can buy a gauge cheaper then a new machine.
http://www.grainger.com/Grainger/ENERPAC-Pressure-Gauge-46C567?Pid=search


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## Oden (Feb 8, 2012)

Bender said:


> I disagree. 2K is a bit high in my opinion and I don't think atomization is relevant for backrolling.
> 
> I disagree with this as well. Back in the day when paint was $12.00 a gallon and labor was $20.00+ an hour, material costs were unimportant, labor was. But now its not uncommon for a man to put up several times his wage in materials a day.


my boss pays bout $12 a gallon for paint as we speak
He pays me $35 an hour plus bennies. 
Material use never enters any conversation.
Production enters every conversation.


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## Bender (Aug 10, 2008)

Are you hiring?


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## slinger58 (Feb 11, 2013)

What a wild and wooly thread this has been. I think the OP was looking for a "Ben Stein" like discussion on fluid pressure/airless spraying/backrolling and look what he got. That's what I love about PT. :thumbup:


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## TJ Paint (Jun 18, 2009)

miket said:


> The graco spraying guide tells you to increase the orrifice size when you get tailing. That's vague and hypothetical?


Maybe look into hvlp options for optimum transfer efficiency. Vaya con Dios bro!


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## chrisn (Jul 15, 2007)

TJ Paint said:


> Maybe look into hvlp options for optimum transfer efficiency. Vaya con Dios bro!


 
This is your third answer after saying goodbye


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## TJ Paint (Jun 18, 2009)

chrisn said:


> This is your third answer after saying goodbye


I try too hard sometimes. Then I get caregivers fatigue.


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## chrisn (Jul 15, 2007)

I forgive you


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