I purchased a cheap HVLP gun at HF to do some spraying. The question I
have is about pressure. the manual states to run it about 40psi, and
never run it higher than that. i have a small regulator at the gun, and
one at the compressor end. when i set the compressor regulator at 45, i
get about 40 at the gun (i have to use about 75' of 3/8" hose to get
where i need to spray as the compressor is a large tank in the
garashop). however, when i start spraying, it drops down to the 20 psi
range whilst i'm spraying, and going back up when i release the trigger.
when i crank the pressure up at the compressor regulator, the pressure
then, of course, goes up at the gun. when i start spraying, the pressure
drops pretty quickly, then rises back up when stopping spraying.
this is my first experience with an hvlp, so is this normal? is the
20psi during spraying good enough? it seems to be spraying a pretty fine
mist at 20psi when i did my testing with plain water.
what i'm spraying is mostly water anyway, so it shouldn't be too much
Keep the pressure up at the compressor, just about at its limit. You
are going about it correctly by controlling the output to the gun with
a separate regulator at the gun handle. More compression behind the
gun will assure you that your compressor will not cycle as often as
I have a couple of those HF HVLP guns and they are surprisingly good.
I don't know your model (not that it would matter) but I usually find
the sweet spot for spraying at about 12 - 18 pounds at the gun. If
you are shooting at 40psi to the gun, no doubt you are draining your
compressor quickly. Remember, High Velocity, LOW Pressure.
If you can't get your material out at lower pressures, thin it out
more. When I was learning to shoot with a HVLP gun powered by a
compressor, I set it up like a high pressure gun. My compressor
couldn't keep up, I had lots of overspray and drift, and didn't see
any savings in material. After really woodshedding that gun and
getting some excellent advice, I got it to where I want it.
Remember, and HVLP setup will not atomize your finish material the way
an old fashioned high pressure spray will. It isn't designed to work
that way, hence, it simply won't.
Shooting water shouldn't be a trick for any gun/compressor at any
pressure. Keep the pressure low, and adjust your feed and pressure as
needed to keep the water flowing.
On 11/16/2011 12:36 PM, firstname.lastname@example.org wrote:
it's usually used for sandblasting, so is a large tank and relatively
large pump. i ran a test for about 15 minutes with plain water, and it
never kicked on to refill. the tank fills to 125psi but the regulator
there is normally set to 75 for blasting.
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