On Jun 14, 11:16 am, "
wrote:
On Jun 14, 9:34 am, Lincoln Terns wrote:

SNIP

He suggested that I experiment until it works and then record the ratio, which is exactly what I don't want to do. Does anyone know to what scale this cup correlates? Or, does anyone know where I can get a standardized cup?

I have the Q4, and have been using it regularly in my business for
about a year and a half. I love the machine, but to shoot industrial
grade products there is a curve, just like there was/is with high
pressure. And since thinning to correct viscosity is an essential
with HVLP, I haven't found any other way to get the coatings prepared
for application than experimentation.

Some coatings require no thinning, especially is you purchased a 4
stage unit. But the very same coating will require thinning on a 60
degree day that it doesn't need on a 85 day.

My favorite clear coating is a little expensive (+/- $45 a gallon) and
it shoots like glass from a high pressure gun. But with my HVLP, it
was like starting over when I used it. I never fiddled with different
speeds of thinners etc., and kept such exacting notes based on
temperarture and humiidity before. Since I was learning both machine
application process (I had only used a compressor powered HVLP gun
before), and thinning ratios at the same time, by the time I got it
where it was putting down a satisfactory coat I had run through a
hundred dollars worth of material on test plywood.

But before I got it where I wanted it, and before I got to where I
would confidently roll up on job and get set up to mix and spray in
someone's garage no matter what the temperture or conditions I
probably spent another $250 on material and thinners, not to mention
my labor. I did all that because I can't afford to experiment or
learn on a client's property.

The same happened with my industrial coatings, but not so much
experimentation was required. Still, the formulas are different from
the high pressure days. As a rule to start, I thin by about 10% more
for them than I did with high pressure spraying to make the coats lay
down properly.

And now many manufacturers are starting to make different coatings
that require no thinning when using HVLP. It has been my experience
though, that colored coatings are behind the clear coatings on this.

As far as the cup goes, if I were you, I would toss it. If you worked
in a climate controlled shop all day long, same temps, same humidity,
same airflow, etc., then the viscosity cup might have some merit. If
you are spraying in an open shop or outsided, the cups are pretty
useless.

As painful as it might be to burn the matrial, I would start mixing up
1/2 quart batches in the cup and trying them out. I just consider
that aspect the same as the curve to learning proper to use any other
tool.

I would also take a minute and call the number on the can and ask them
1) where to start thinning to prepare for application and 2) what is
the most amount you can thin and not harm the material.

Good luck!

Robert

Robert,
Thanks for the thoughtful and comprehensive reply. I definitely
understand that, without a controlled environment, trying to isolate a
variable is going to end in fustration. I'm just trying to get in the
ballpark for one variable before attempting to blend in all the
others. I spray a lot of different materials on a lot of small and
diverse projects and am trying mightily to shorten my learning curves.
As for myself, I'm just a hack doing this for my own amusement so any
experimenting is money out my pocket and, at $35 a quart, is an
expensive proposition. I did contact the manufacturer who claims the
stuff can't be sprayed with HVLP equipment but I suspect they're not
allowed to tell me to thin it out past VOC compliance regs. And I also
suspect that your belief that there is no shortcut is probably
correct. Oh well, back to the test board...