Turbine HVLP vs Paint

Steve1 said:
I still have no idea where I am going wrong.  But I don't give up easy.
Any suggestions ?
Looking back at my previous results, the only places I got beautifully smooth finish is where I overlapped the spray on the rails and stiles --- so simply not thick enough ?

Your tenacity leads me to believe you'll find great results AND be able to recreate them.

If you're getting a desireable finish in the overlapped areas and there are no drips or runs anywhere else you probably just need to lay down more material. There are several ways to go about this. Get closer, increase overlap, increase fluid flow to air ratio. If youre worried about runs, sags, practice on some folded construction paper(according like) to see how easily runs start.

I don't stop spraying the if the sheen isn't fully glossy and uniform in my reflected light source. The square edges become a bit round and bulbous, and by all means it "looks" like it may end up with runs or drips. But if I was fairly methodical with the application and thoughtful in respraying dryer areas, and the viscosity is close(doesn't even have to be perfect) usually there won't be drips. Any I do find, I'll fix by immediately pulling paint off with a dry brush. With today's paints, if the material holds for the first few minutes, you're likely good to go and drips won't magically materialize overnight like they used to.

Though not great, it's def not end of the world to get a small drip or run. If you get 99% of the project perfect a touch up or two usually goes unnoticed, especially after a week passes. :) You can always spot treat a single area and usually you catch the run while nice and wet, so by removing a bit of material with a brush, it lays down just as flat as everywhere else.

Attached is an example of how heavy you can coat without defects if spraying on horizontal surfaces. Once dry, all doors were perfect, zero touchups needed. And even with this heavy a coat, it still took 3 coats to get that really luxurious finish you're probably after.

Keep at it. You're close.
b29308fd3ae629d96127911a55b91328.jpg

 
Steve1 said:
Have not been tracking volume.  I have been working towards a viscosity target.

What viscosity would you suggest I target ?

I'm with Packard's 90-ish+.  That's the lowest I get with some of these thicker paints and primers.  I keep a keen eye on the % dilution, which each paint will specify max - but for those without, it's usually going to be 10%.  If I hit that and I'm still not dripping right on either stick/ford tests, then you have some options:

a) warm up the pot (water bath) before the dilution tests/usage
b) use a bigger nozzle
c) switch to a retarder

 
makpacman said:
Attached is an example of how heavy you can coat without defects if spraying on horizontal surfaces.

Wow.

I was definitively too thin.  There were a couple of small marks on the surface of the door, that I could still kinda see after spraying.

Thank you
 
Steve1 said:
I have a Fuji 5 stage turbine unit and the small G-XPC gun.  Normally I use it for spraying water based poly, but this week I decided to learn how to spray acrylic paint. 
I am painting doors, laid down flat.  It can't get an easier than this.
Not going very well so far.

I am using Benjamin Moore Regal Select semi-gloss (35.5% solids)

First two attempts were definite failures and I will spare you the details.

Third attempt, I am getting closer.  1.8mm nozzle.  I thinned to 27 seconds on Ford cup.  Some Floetrol, but mostly water. 
I narrowed the fan to get better atomization, but then I had to open up the fan size somewhat because spraying white on white I had a hard time seeing where I had already sprayed.  Distance about 6".  Not bad, but I could see a higher gloss level where (I expect) the paint went on thicker.  Having difficulty spraying a "wet" surface.   
View attachment 1

Fourth attempt (different door) I thinned to 33 seconds.  Some Floetrol but mostly water.  1.8mm nozzle.  I kept the fluid flow low to get good atomization, so I was moving the gun painfully slow and taking multiple passes.  On a practise sheet, when I opened up the flow more, I started seeing spatter on the outside of the fan.    I got closer with the gun, about 4-5"  Still, I was not seeing a wet surface, so increased the fluid flow.    I could see the air from the gun making ripples on the paint on the surface.  But at least it was a wet surface.  Not really orange peel, but not a smooth surface either.  (photo is only 2 hours later)
View attachment 2

First the basics -
What should my target viscosity be ?
How far should my gun tip be from the workpiece ?

Any advise on how to achieve a good wet surface without opening up the flow too much ? (that was attempt #2, had to sand)
I have the MiniMite 4.  You seem to be doing everything correctly but let me add:  First of all, you are spraying too close, Keep your spray gun at least 8" minimum from the surface.  Use the 1.8 air cap for latex paint. Don't be timid with the "Material Flow Control knob". open that sucker up at least 3 or 4 turns.  I use to open it maybe 1 1/2 turns and my T75g gun would spit paint (#4 Ford cup at 30 seconds for Latex Enamel).  I kept thinking what I was doing wrong.  So I opened up the Flow control knob and forced myself to hold the gun 8 - 9" from the surface I was previously 5 or 6" from the surface.  Then I turned the flow down incrementally until the paint was spraying well  (usually around 2 1/2 to 3 turns).  I started seeing improvements right away.  Best of luck
 
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