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Thread: Spaying Heavy Paint with a 3-Stage HVLP ?

  1. #1

    Spaying Heavy Paint with a 3-Stage HVLP ?

    Hey, folks.

    I've been away from doing projects for a long, long time.
    Doing a project this week which requires my using an HVLP system which I bought long ago, and never used.

    The basic system is a Turbinaire Minipro Plus, with the original CX gun. I also have an Accuspray Series 10 gun, with the mini regulator & gauge.

    I also have a huge assortment of tips & needles for the Accuspray gun.
    ----------------------------------------


    MY PROBLEM / QUESTION:

    This turbine is only 3-stage, rated for 130 CFM @ 6 PSI. Unfortunately the stuff I'm about to spray is Rustoleum Multispec, which is water-based but very thick. - And I have to spray several gallons of it. They recommend a 4-stage system, but that is out of the question.

    I'll also be first spraying KILZ Original Interior, which is a thick oil-based primer.


    Any tips for getting through this job with what I have? I'd rather not thin the paint as that could compromise the "multispec" look, but I will if I have to.

    Maybe use an extra-large tip or needle?


    - Thanks.
    Last edited by Allan Speers; 11-30-2021 at 5:29 PM.

  2. #2
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    When you said you need to spray gallons the first thing that comes to mind is you might be better off looking into renting an airless sprayer than trying to use a system that's going to be challenged, at best.

    You can try thinning the Rustoleum up to 10% and see how it sprays with what you have. Measure the viscosity and match it the recommended needle or as close as you have. You can probably thin the OB primer as much as you want to get it to spray but you'll likely have to spray at least one extra coat. Spraying OB anything indoors makes me shudder just thinking about it.

    John

  3. #3
    Thanks, John.

    No I'll be spraying outdoors, with a wind-break fabric set up. I just have to wait for a warmish day.

    Good idea about thinning the primer and multiple coats.

    I can't thin the Multispec, though, unless I want to take a chance on changing the look. I never thought I'd be spraying this stuff when I bought the Turbinaire. I should have bought a 4-stage. (Well, I bought it used for a crazy-low price, so....)

    Rustoleum also says to NOT use an airless sprayer, though they don't say why.

    I guess I might be able to rent a more powerful HVLP somewhere, but I'd need it for several days, and money is REALLY tight these days. (The pandemic killed my business.)
    -----------


    Any suggestions for tip / needle and cap sizes?
    Last edited by Allan Speers; 12-01-2021 at 1:32 AM.

  4. #4
    Another question just occurred to me:


    My Turbinaire system is designed for a bleeder gun.

    I bought the Accuspray #10 separately, and again have never used it. This is a non-bleeder type, correct? (I am somewhat clueless right now about HVLP)
    The pot itself has what seems to be a pressure relief knob. Is that what it's for? To let air escape when using a turbine that has no relief valve?


    If this is purely a non-bleed gun system, is there a way I can use it with my turbine?
    I do have a 93-025 regulator, (Which is called the 3600 in the users manual, for some reason) but AFAIK that's for use with a compressor, correct?

    I read that on older Fuji turbines you can actually drill a hole in them, to let air always pass over the motor, but of course mine is not a Fuji.

    I also see that in a 2012 post here, member Mike Mesner mentions that he had an adapter from Turbinaire to allow him to use a non-bleeder gun with his Turbinaire system.
    Are those still available, from some other manufacturer? (I assume it's just some kind of bleeder valve that would go inline with the hose, correct?
    Last edited by Allan Speers; 12-01-2021 at 2:05 AM.

  5. #5
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    Alan, you need to spend some serious time practicing/testing/adjusting your setup with that finish to be sure it's going to work for you and give you acceptable results. I do not know your system or your guns, but I suspect the bleeder is a non-starter for this application. For the other gun, you have some pressure to help, but you may need, if you do not already have it, a pretty large needle/nozzle setup to move a thicker finish like you describe. You may need to burn a lot of finish just to get a setup that works, so be accepting of that time and cost to get it right.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  6. #6
    Thanks, Jim.

    Are you saying the non-bleeder gun has more pressure?
    That would make sense, except don't I then have to have some kind of bleed valve on the turbine or hose? (or at least a pressure relief valve?


    As for caps & needles, I have a huge set, so I'm good there.

  7. #7
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    A bleeder "sucks" the finish out through a venturi effect as air passes through the gun. Great for low viscosity products (despite the annoying noise) but not so good for heavy stuff, IMHO. Bleeders are simple devices...the most simple example is the ever-popular "Critter" setup that you can use with a jar.

    I've never owned a Turbine system so I cannot comment on that architecture. All my guns run from compressed air, either a typical HPVL conversion gun (only used for shellac at this point) and the gun I got from Jeff Jewitt that has the 3M PPS cup system which uses pressure to force finish through the gun by compressing the flexible plastic cup liner as finish is requested by the operator. That thang can spray almost anything with proper setup.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  8. #8
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    I sprayed drywall primer with my Earlex 2 stage and a 2.0 needle. I just thinned it till the Ford cup said it was good and it sprayed without issue. If you cannot thin, look at renting an airless unit for a few hours.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  9. #9
    Well, you guys made me question the sense in all this, so

    I just picked up a used 4-stage Titan Capspray 95 system. It does 9.5 psi and is already a non-bleed system.
    I can't really afford it, (This bloody pandemic...) but the price was good & I can now sell the other stuff.

    Rustoleum even OK's this exact system for their Multispec paint, un-thinned.
    I'll probably still thin the primer, just to make things easier. (And maybe a more even coverage, by doing 2 thin coats.)


    I'll have to use the Accuspray 10 gun, though, as I already have a large collection of air Caps, needles, etc for it. I'll sell it off, after the job is done.

    -------------------------------------------


    Thanks for all the info and thoughts, guys.

  10. #10
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    My understanding of bleeder vs. non-bleeder (as explained by a Graco sales rep at a paint store many years ago while I was a painting contractor):

    A bleeder gun does not control the atomizing air with its trigger—the trigger only opens the fluid needle. A non-bleeder gun will not have atomizing air flowing through it when the trigger is not depressed—the trigger controls both the atomizing air and the fluid flow. Bleeder guns are thus more suited for turbine systems, which can be damaged if they run too long without moving air (and the air gets really hot). Non-bleeder guns are better for use with compressors, which don’t run continuously, nor do you want them constantly “bleeding” off air.

    Either can be setup use the venturi effect to draw fluid into the airflow, use a gravity feed, or use a pressure pot.
    Jason

    "Don't get stuck on stupid." --Lt. Gen. Russel Honore


  11. #11
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    My recommendation stands for you to spray a bit of the finish to be sure you have things dialed in to get the quality of finish that you want with that specific product. And you need to do the same for other products...and take notes so you can get close to that same setup next time.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  12. #12
    Jim.

    Yes, I will definitely experiment & practice first. Thx.
    I'll also have 2 non-bleed guns to try (The Accu 10 and the Maxum II) if I get a large needle-cap set for the latter. Plus I have the Turbinaire CS bleeder, also set up with large flow components.

    Interestingly, I read that bleeder guns can actually be better for atomizing thick latex, due to how the air moves through the pot. - But of course then you need an extra-powerful turbine. Capspray's guns can easily be switched from bleeder to non -bleeder, evidently for this exact reason. I assume most good guns can do the same, with the appropriate inlet plugs.

    --------

    Jason, you are correct, but evidently the more expensive turbines are designed for non-bleeder guns, and thus have some sort of air escape valve internally. I guess maybe these open when the motor starts to get hot, to cool it, but close again so as to keep maximum pressure to the pot for as much as possible. - But I'm just guessing on how they work.

    To safely use a non-bleeder gun (like the Accuspray 10, 19C, etc) on a turbine that was designed for a bleeder, most folks recommend adding something like the Apollo relief valve to the turbine's output connector: https://www.paintsprayersplus.com/Ap...p/apa7538a.htm
    Unfortunately for me, the Turbinaire MiniPro I was going to use has a 7/8" outlet, whereas that Apollo valve (and almost all other turbines) use 3/4". I found a thread adapter but it was crazy expensive.

    There's also this interesting "HVCLP Adaptor" dingus, which claims to increase pressure at the gun on marginal systems:
    http://www.refinishersonline.com/sto...t_version=true
    It might have worked, but when I added up the cost of all the mods I needed to do, it made sense to just buy a different turbine.
    Last edited by Allan Speers; 12-02-2021 at 1:52 PM.

  13. #13
    Well, I still have one big decision to make, maybe you guys can help if you have the time to absorb this:

    I need to decide if I should use a bleeder or a non-bleeder for this job.

    I will be spraying very heavy Multispec latex, with a 9.5 psi 4-stage turbine, so I'm already on the edge.
    The paint is NOT supposed to be thinned, though I will take a chance and thin it a little bit, and maybe also add a little Floetrol. (I'll experiment first)
    The paint is also supposed to go on with ONE pass, which is an extra problem.

    But the good part: This is multispec paint, and it's being applied to 3-dimensional acoustic diffusors, so the one thing it does NOT have to be is flat & smooth.
    So here's my thinking, based on zero experience:
    ---------------------------------

    While a bleeder will help atomize the paint, if I understand correctly, it also creates less pressure behind the paint, since some air is always escaping
    IS THAT CORRECT?


    Since I need a huge flow of paint, much more than I need a smooth finish, I’m thinking that a non-bleed setup would be best here.

    - And maybe also get that HVCLP adapter, which basically turns the siphon cup into a pressure pot, putting maximum air pressure behind the paint.

    (Or get a 2 quart pressure pot, but I can’t afford that right now.)


    SO, does this sound correct and logical?

  14. #14
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    I think you’re still missing what the role of bleeder vs. non-bleeder is. A bleeder simply flows air even when the trigger is NOT pulled—bad for a compressor, good for a turbine. It has nothing to do with flowing the paint.

    A turbine will not work with a pressure pot, unless you use a separate compressor. In your case, with a heavier paint, a pressure pot would be a very good way to go. You can take the pot to 20 or 30 PSI, which will reliably push that paint up into the airstream in the gun.

    One more thing. If this is the MultiSpec that I’m thinking of (but never used), you may not want high atomization. The coating I saw many years ago had globules of multiple colors suspended in a latex. The idea was to spray it without breaking down those globules too much to get a flecked effect in the coating. Think closer to “spitting” the finish than misting it.
    Jason

    "Don't get stuck on stupid." --Lt. Gen. Russel Honore


  15. #15
    Hey, Jason.

    No, Yes&No, and yes good point.
    (I made a lot of phone calls yesterday, and the fog is starting to lift. )


    1: A bleeder atomizes slightly better because the air is already moving at full speed before the fluid hits it. This has been confirmed now by numerous experts.

    Having said that, it turns out that my Capspray Maxum II gun doesn't HAVE to be converted to a bleeder, because it has a 2-stage trigger: You pull it half way and it starts the air. Then you pull the rest of the way and it starts the fluid. - Reversed when you stop. They also make it so it can be converted, because some users find that to be more convenient when spraying very viscous material. You don't have to constantly remember to use the trigger correctly.
    Also, some like the fact that the air hose then attaches at the back, as this makes it easier to get into small cabinets & such.

    I also now understand that there is no difference between the two gun types, as far as how much pressure there is to push the paint. They both rely on suction from the venturi.
    - That was really puzzling me for a while.

    The main downside of a bleeder, as far as I can see, (besides constant airflow) is that you lose the ability to control how much air flows through the gun. - Although I don't know why that has to be the case. Maybe just to keep the cost down.

    -----------------------

    2: A 4-stage or larger turbine WILL work with a pressure pot, but it's recommended to only use a 2 quart pot. (The 20-30 psi pots you're talking about are made for use with shop compressors, & they are completely different.) I'm told that even with a 2 qt, a 4-stage turbine is very marginal, since the fluid has to flow through a long thin whip hose, plus two 90-degree fittings. Thats a lot of back pressure. But a 4-stage should work if you use a very short whip hose, and keep the pot in your hand or on your belt. (There are several Youtube videos showing guys doing this, even with latex.)

    Also, you need to be using a gun that works well with pressure pots. Evidently some Turbine-type guns do and some don't, having to do with the construction of the air caps. Luckily, the Maxum II is designed for both. I'm not sure about the Accuspray 10 though. I'm still trying to find out.

    -----------------------

    3: Yes, definitely. This is a big problem that I have to be aware of. ( thx )
    It's going to take a lot of experimenting with nozzle size, thinning, etc.

    So when you say "not high atomization" I assume you mean what I asked about above, yes? Higher fluid flow but less air, trying for a thicker rather than thinner material coming out of the gun. - How would you set the system up to achieve that?

    I'm think I'll get one of those HVCLP adapters. It basically turns your suction cup into a "sort of" pressure cup, but without the pressure loss that an external pot creates. You get air pressure behind the paint, helping it p the suction tube, so the gun's air control can be lowered without too much loss of fluid flow.
    The guys at Hawke Labs swear by it. they make a paint similar to Multispec, called "Stoneflecks," and they say this adapter makes a big difference when spraying with a 4-stage, even a 3-stage.

    So I figure that with that adapter, and the right choice of large needle / air cap, I should hopefully get decent fluid flow and yet be able to turn down the gun's airflow. (I'd have to keep it in the non-bleeder configuration, so as to still have that adjustment knob.)

    =====================================


    I'm still just guessing, and would love to hear more suggestions, but I think I'm on the right path ....
    Last edited by Allan Speers; 12-04-2021 at 4:29 PM.

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