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HVLP adjustment ramble..........

2K views 9 replies 8 participants last post by  crazy larry 
#1 ·
Hey all. in my recent foray into painting, more specifically priming and sealing, i have made a few notes and have a few queries...... I have attached a pic of my gun. it's of Taiwanese decent.

while shooting, i used the plastic back drop to adjust and tune the spray on, it was really enlightening as to what affected what, as far as adjusting this knob, or that knob, etc. etc.......

so my main concern is how to best adjust it. i noticed that i got what seemed like excessive over spray, ie; when i got through, there was a fine 'dusting' covering the surfaces of the truck. maybe i didn't have enough air OUT? as in ventilation..... or is the air pressure to high at the tip? i'm running 80 psi off of the tank, into a coil hose to a h2o separator,into a pvc pipe app. 35' to a 25' hose to a disposable drier to the regulator on the gun, set @ 50 psi. the chrome screw set at the base of the gun,(left of the air inlet) that is air pressure control right? i can crank it down, and it helps, but you get to a point of diminishing return, where then it begins to 'splatter' the paint, ie; not a fine mist. i've tried turning the paint flow knob down in conjunction with cutting back on the air , and just don't get the results i think i should be getting......

i'm running the paint needle (a 1.3) 1 1/4 to 1 3/4 turns out, i seem to be getting good paint coverage with that, any more and i get big particles instead of the mist. ......

maybe i just need to play with it some more.

how do you determine psi at the tip?

any ideas or suggestions?

cl
 

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#2 ·
Turn down your air Larry, at the tank preferably. 60psi is a max for 99% of the painting I have done. Usually 35-45psi is good at the tip. Paint viscosity determines air pressure, heavy paint needs more air to shape the fan.

Is the gun clean?:confused:
 
#3 ·
oh yeah. i took it apart between the primer and sealer and scrubbed good. i'm surprised and happy with the way this thing comes apart and all. really neat. (dork. i know.) but any way, yes, i feel it couldn't be cleaner.

i saw some one post awhile back, stating, something to the effect of you could over clean your gun, actually not damaging it with cleaning, but destroying the needle seat.....??? or something to that effect......
but my needle seats into a steel hole, nothing not steel involved...
so is that a concern, or only on high end guns....?
 
#4 ·
I understand that you are talking about a HVLP gun?

I thought they operate on lower pressures, hence the name HVLP (High Volume Low Pressure). Those pressures seem high to me, but then I still use a conventional gun, and my pressures are normally at 35-45 lbs. You might want to check the documentation for the paint and gun for their recommendations.
 
#7 ·
Hi Crazy
After owning my Binks HVLP for eight years. My recent experience with the '47 Willys restore has answered that same question for me. I now set the air pressure at the tank discharge (after primary water separation) at about 40 PSI. I use about 25' of 3/8" I.D hose. I have an gun inlet pressure gauge (after secondary water separation((little plastic ones)). I set this inlet pressure gauge at 18-20 -PSI. (Note: saw an earlier post that these gauges can be off significantly).The local experts tell me that the tip pressure will never exceed 10PSI no matter what the inlet pressure gauge says. That's because I'm told the gun is internally regulated to deliver not more than 10PSI. Before that, I was setting the inlet gauge at 10PSI and was getting overspray MAXIMO! Guess the tip pressure was down to 5-6 PSI. So anyhows, the gun works just fine with above settings.

Always a good idea to spend a little time shooting against a practice surface when you're just weekend hackers like us, guess the pros can set their guns blindfolded. Also I've found the pressure wants to jump around as you ad/subtract paint with the knob plus also when changing from fan spray to cone. try this and watch the inlet pressure. My Habor Fright HVLP has a air volume knob ?? at the bottom of the handle, didn't know how to handle this new and exciting control so have just left it wide open??

Lastly, being real paranoid about runs, I found I really wasn't putting enough color on(single stage). Better to have a few runs than paint too thin + overspray.

I'd sure be curious if anyone out there has had similar experiences??
 
#8 ·
I have recently purchased a devillbiss finishline hvlp. I haven't had a chance to use it too much yet, so I'm not entirely sure what works best with it. If I remember correctly, the instructions say it needs 8-10 at the tip. They say that to get this, the inlet pressure needs to be 18-20. When I've used it, I put the inlet pressure at 20 and everything seemed fine.
dh
 
#9 ·
Hey Larry,

If you notice in that Sharpe Link, their T1 HVLP gun has a recommendation with S-W paints as follows: Inlet pressure 30 # = 10 # at the cap.

Your gun is very similar to the one that I use for primer and POR15 frame spraying. I usually use between 30 - 40 # at the regulator, with 3/4 of a turn on the paint feed, using a 8 by 8 distance to the material by width of spray. Hope this helps.
 
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