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Pressure for wide spraying

Discussion in 'Beginners Airbrush Questions!' started by SiRoxx, Apr 2, 2018.


  1. SiRoxx

    SiRoxx Party Boy UK Style Very Likeable!

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    Hey Guys and Girls,
    Other than the specs of the brush and compressor, is there such a thing as “too high a pressure” for spraying a wide background section?
    Let’s say I want to let her rip to lay candy over an entire piece. Does a higher pressure equal better atomisation or can it be too high?
    Many thanks in advance.


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  2. JackEb

    JackEb The Dragon Hunter Staff Member Admin

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    As far as I’m aware it all comes down to the ideal pressure for the paint being sprayed,
    Eg: with over reduced paint it may atomise perfectly at 20psi and if you push it to 50 you’re going to have to move rapidly across the surface to avoid runs/spiders
    Unreduced paint may spray perfect at 35psi

    I guess what I’m trying to say is that psi has more to do with the paint in the cup than the amount of coverage required.
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  3. Mr.Micron

    Mr.Micron Royal pain in the air hose Admin

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    According to what I have been told you never want to take your airbrush over 90 PSI. you run the risk of blowing seals .
    With HVLP and LVLP guns of today you should never really have a need to go above 40 PSI,
    If you're doing t-shirt art work most stay at around 50PSI
    and as Jackie stated for any airbrush work not done on textiles 35 PSI is about max.
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  4. SiRoxx

    SiRoxx Party Boy UK Style Very Likeable!

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    That makes a lot of sense. Thanks Guys. I should she also mentioned that following the directions from the manufacturer goes without saying.
    My compressor is only man enough for around 40psi anyhow, so plenty for a round cap airbrush, but it was just a general wondering.


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  5. jord001

    jord001 Air-Valve Autobot!

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    You may also find that your airbrush will only spray paint at a certain volume. Even if you have 80psi going into the airbrush, it can only let so much air through its tiny airways. Cant tell you the actual volume in lpm or psi but its not going to be massive. The eclipse running at about 40psi is pretty good for candies. More coverage needed usually = larger nozzle.

    You could have taken my small spray guns back with you to try when you were only 10 minutes away from me.....

    Lee
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  6. SiRoxx

    SiRoxx Party Boy UK Style Very Likeable!

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    I do appreciate the offer buddy but the compressor is 80l/Min maximum, so I don’t think guns will be an option. This was more a general wondering.


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  7. huskystafford

    huskystafford Needle chucking Ninja

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    here is something which can maybe help you with your general wondering


    guy makes few different tests
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  8. SiRoxx

    SiRoxx Party Boy UK Style Very Likeable!

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    Thanks Husky.


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  9. JackEb

    JackEb The Dragon Hunter Staff Member Admin

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    if you are looking for a good coverage gun, without going to a spray gun, what about the Iwata Kustom TH ?

    has a fan cap, larger cup

    upload_2018-4-3_6-53-23.png
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  10. JackEb

    JackEb The Dragon Hunter Staff Member Admin

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    Interesting..........
    i checked the manuals for the Eclipse/HP series, and it states a max of .29 MPa (42psi , 2.9 bar)
    upload_2018-4-3_7-13-6.png


    For the Kustom TH I mentioned above, it states the operating pressure to be between 10 & 45 PSI

    .
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  11. SiRoxx

    SiRoxx Party Boy UK Style Very Likeable!

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    That’s absolutely what I’m doing Jackie, so good call. I honk I’m going to go with the Mr Hobby variant. It’s about £100 cheaper and they have had really good reviews. DaveG thinks a number of the components are identical to Iwata and probably come from the same factory. So it seemed like a safe bet.
    I’ve tried spraying Candy through the Eclipse and it works fine, but a fan pattern brush will be better.
    With that in mind the CFM obviously comes into play. I need a relatively quiet compressor and can’t afford a quiet one that will run a mini gun. But I can afford one that will run a fan pattern brush.
    I think one like that will be exactly what I’m after.


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  12. huskystafford

    huskystafford Needle chucking Ninja

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  13. SiRoxx

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    I’ve seen those Husky, they look like a great option for an existing Grex Brush. But I don’t have any Grex brushes and the dealer for Mr Hobby isn’t much of a drive, so getting parts and smaller items without paying shipping helps out.


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  14. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

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    As general wondering goes heres what you run into.
    If the pressure is too high it will start pushing the paint on the surface, forcing you back away. You back away so far and more of your paint ends up in the air than on the surface your spraying.
    The lowest pressure you can run that gets you sufficient atomization is what creates ideal transfer efficiency.
    So even if the gun can handle the pressure, having to spray from more than 6-8 inches to avoid ripples with basically any brush or gun means your transfer efficiency is way down probably 50 percent or lower.
    Also if youre too high a lot of what hits the panel actually bounces off back in the air.
    You can see it happen on a spray can or old conventional, espcially if you stand back. Kind of looks like a cloud around the spray pattern for about 2-3 inches off the piece.
    old conventional guns and cans that have you spraying from 12-18 in away had transfer efficiency at like 30 percent.
    There are certain paints where its necessary to do that to get a good finish but thats the exception.
    In the extreme you could actually run so high that you have to back away enough that everything that hits the surface is dry sprayed.
    Also metallics can get where they seperate, liquids mostly in the air and particles are mostly what hits the panel.
    These are ballpark generalizations and estimates but anyhow.
    Last edited: Apr 25, 2018
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  15. SiRoxx

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    Appreciate it Mate thank you. I’ve landed on the Mr Hobby fan brush after rave reviews from DaveG and yourself. I’ve found a compressor that will run it and for my needs well too, so now it’s just a case of building up the funds to get the new kit. It’s one of those Orazio compressors.


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  16. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

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    Sounds like a cool setup! I haven't tried the 290 but the mr. hobby quality ive seen is awesome and i'll probably end up with a 290 as well for the same reasons. Covering those times when i need to use the mini compressor and do larger areas. I ended up buying a senco pc1010 compressor for my brushes, just because I happened across it at a pawn shop for $10 because they thought it had a tank leak but it was just the regulator.
    I love my mini guns but the senco and a 290 are gonna fill a convenience gap where i dont have to lug a 60lb devillbiss compressor out to run the mini for some touchup.
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  17. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

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    But yeah I was just trying to answer the general sort of "why cant you bump the pressure up to whatever" curiousity.
    Anyhow which orazio are you eyeballing? just out of curiousity.
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  18. SiRoxx

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    Absolutely and you covered it great thanks Buddy, Id learned about having pressure too low, but had no facility to learn why it’s not great to have it too high either.
    The compressor is the 241174, 24l Tank. That should be fine for my needs and looks like it might run an ANI r150 with one of the smaller nozzles. So I figure it’s a good balance of noise, size, cost and gives me the option of a Mini Gun if needs be in the future. Reviews seem to be good too.


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  19. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

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    It'll run an r150 fine. Its got specs just slightly under my devillbiss compressor, volume wise but a third larger tank. I run mini guns all day long off of it (just not absolutley constantly). The cfm on the compressors are usually rated at 90 or 40 psi or both, but the mini guns you usually end up running 25psi so you end up effectively having 1.5 times the flow from your compressor that your rated at so youve basically doubled the requirements for an r150. You wouldnt want to use it in like production spraying where you literally are on the trigger for hours at a time but any projects should be fine.
    Using a mini gun on my 6fm devilllbiss once it kicks and i keep spraying, it shuts off 30 sec after i let off the trigger.
    The orazio might take a minute or two but it should stay in its duty cycle for anything you would use an r150 for.
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  20. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

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    accounting for the orazio being chinese and probably a bit over rated youll still be ok i think. Not pushing it too hard

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