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Setting up a mac valve?

Discussion in 'How to Control an Airbrush' started by RichardH, Oct 8, 2017.


  1. RichardH

    RichardH Elite Member! Elite Member!

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    I am considering on buying a mac valve for the Iwatas I have.
    What pressure would the compressor need to be set with the pressure valve and what position does the mac valve need to be set up at?
    I am thinking the compressor needs to be adjusted to 35 psi and the mac valve needs to be fully open. Then start adjusting the mac valve for the pressure needed.
    Then again do I need to start with the mac valve fully closed and start from the low end first.
    Those that use them, how do you work the mac valve with your setup?

    Richard
  2. Ronald art

    Ronald art Detail Decepticon! Very Likeable!

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    the way I use the mac valve is easy I have set the pressure on my compressor to the max I need to operate all my airbrushes with paint straight out off bottle .
    I have 2 different mac valves the Iwata mac valve straight to my main airbrushes and a grex mac valve I use for the airbrush I dont use every day .
    I adjust the pressure I need with my mac valve and it depends on what airbrush I use and if I thin my paint .
    the way I do it is I turn down the pressure with the mac valve till it is nearly closed and test spray while adjusting the pressure till I get a perfect line and no spidering
  3. RichardH

    RichardH Elite Member! Elite Member!

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    Hi Ronald, been a while since we have chatted. Hope all is going good on your end. Is the Iwata mac valve very sensitive with the knob when turned or is it turn a little and get a lot of pressure change. I can adjust the compressor valve but it is not a fine tune psi adjustment. Turn a little, get a big change with that.
  4. JackEb

    JackEb The Dragon Hunter Staff Member Admin

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    I had 3 iwata external Mac valves, all are now in a drawer somewhere - it was about 1/8th if a turn between nothing and everything- horrible.
    I know have a grex quick connect Mac valve and it’s brilliant. One valve and all my iwata brushes are now Mac controlled :)

    I set compressor at 40psi with the trigger pressed on the airbrush and Mac valve wide open.
    Last edited: Oct 8, 2017
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  5. RichardH

    RichardH Elite Member! Elite Member!

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    Thanks Jackie. I'll check that one out. I'm not sure if I actually need one but no way to know unless I try something else than what I have.

    Richard
  6. JackEb

    JackEb The Dragon Hunter Staff Member Admin

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  7. jord001

    jord001 Air-Valve Autobot!

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    I have the Grex as my main one and a cheap no brand on my other hose. The Grex has great control but the cheaper ones are a bit like the Iwata ones Jackie has, with not much air control. I set my main air to just under 2 bar or about 25psi with mac open. Then i close off the mac and do like Ronald does, depends on how thin the paint is to how much the valve is open or shut. Different also on what your painting on. You will find one setting for illustration board but would have to readjust for a hard surface. No correct or incorrect way or setting, its what works for you.

    Lee
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  8. Ronald art

    Ronald art Detail Decepticon! Very Likeable!

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    I agree on the Grex being the better mac valve but I am so used to the tiny movements on the Iwata mac valve in combination with the cm SB it is all I need to fine tune my pressure
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  9. RichardH

    RichardH Elite Member! Elite Member!

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    Thanks for the info. I will go with the Grex. Can get it in a couple of days through amazon. It will be nice to fine tune the psi for paint and conditions without adjusting the filter/valve each time. I have some quick disconnects but some still leak air when plugged in.
    I need to win the lottery. lollollollol
  10. JackEb

    JackEb The Dragon Hunter Staff Member Admin

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    Just make sure you get the one to suit your brand of airbrush
    :)
  11. RichardH

    RichardH Elite Member! Elite Member!

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    Thanks Jackie
    Been there , done that. lollollollol
    All I use now is Iwatas. I do have a couple of badger kromes and a lot of paasche's that I don't use anymore. Might as well get a couple of male plugs to go with them anyway. Every now and then I like to keep them flowing so they don't get lonely. :love:

    Richard
  12. DaveG

    DaveG Mac-Valve Maestro! Very Likeable!

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  13. JackEb

    JackEb The Dragon Hunter Staff Member Admin

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    Make sure the male fitting for the non iwata will fit the g-Mac. :)
  14. RichardH

    RichardH Elite Member! Elite Member!

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    Yea I will order the grex fitting for them so they will fit right.
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  15. AndreZA

    AndreZA Elite Member! Elite Member! Artist of the Month!

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    My compressor is set at 40psi. My Harder & Steenbeck ones let through 100% air way before I've fully opened the dial. Mac valve are not an exact science. You play on feel and sound.
  16. RichardH

    RichardH Elite Member! Elite Member!

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    I have always been a believer that if there is a tool that will make the job easier when you don't have the feeling and knowledge experience, then get it to help the project if the funds are avaliable to buy it. So far I have been able to get by without a mac valve but if it will help control of the air better, then it will be bought.
    Of all the hobbies I have been involved in my life, airbrushing is the most liked. Hobbies have been my limited time of letting life and the problems of the world escape me from them.
    Thanks AndreZA for the info and I will be getting a Grex model. I've read good remarks about them and I have to give it a try. Might not work for me but won't know until I try one.

    Richard
  17. JackEb

    JackEb The Dragon Hunter Staff Member Admin

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    Once you get the hang of the Mac valve you’ll wonder why you waited or how you ever got along without one.
    Andre is right (he’s rarely wrong) that they’re not an exact science and you go by feel.
    If your compressor is set at 40 (or even 30) with all airways open you can then just slowly close the Mac valve to the pressure you need. If your paint is heavily reduced then you could wind up blowing 5psi but you’ll never know because there’s no gauge :)
  18. RichardH

    RichardH Elite Member! Elite Member!

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    I've seen on the internet that Iwata makes a mac valve with a guage with it. Looking at the picture of it, It shows its not anymore accurate with the guage markings than what I have now without a mac valve. That setup would be very uncomfortable to me with all that hanging on the bottom of the brush.
    I am getting used to just blowing air on my hand and adjusting the main dial to adjust the amount and looking at what the guage shows. So far it has worked good enough that way but you are right. It will depend on getting the experience using one.
    This forum has been extremely helpful to me but unless I am slinging paint, nothing helps unless I am doing it. Just takes time to learn.

    Richard
  19. AndreZA

    AndreZA Elite Member! Elite Member! Artist of the Month!

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    If you need/want to be more accurate then get a gauge that attaches to your airbrush stand.
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  20. Ronald art

    Ronald art Detail Decepticon! Very Likeable!

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    there is no need for a extra gauge it is just like Andre and Jack said go by feel and spray pattern :) I stared using one when I learned to paint monochrome portraits and using thinned down paint and controlling the pressure with the trigger was just way to hard for me back then right now I use both the trigger and the mac valve to regulate my pressure I would say 80% mac valve and 20% trigger

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