Vince Pitelka on wed 22 jul 09
Shula Purplelama wrote:
"I recently bought an HVLP sprayer at Harbor Freight. My question is - =3D
does it make a difference what size hose I use to connect the sprayer to =
=3D
the compressor and if so, what size should I use and why?"
Shula -=3D20
If you just bought one of the standard Harbor Freight HVLP spray guns =3D
with the small pressure gauge and regulator mounted on the air input, =3D
then any standard air hose will work. Most standard air hoses are 1/4" =3D
ID. This kind of gun is called a "conversion gun," and it reduces the =3D
line pressure to about 10 PSI right at the gun. Generally, you should =3D
set the regulator on the compressor at about 60 lbs. to make sure you =3D
are transmitting plenty of air volume to the regulator on the HVLP gun. =
=3D
Normally that's the only kind of HVLP gun that Harbor Freight sells as a =
=3D
separate unit. The ones that take a larger-diameter hose are the true =3D
HVLP guns driven by a small turbine-type rotary compressor, and they are =
=3D
sold as turbine, hose, and gun all together. Those generally have a =3D
hose that looks like an undersized vacuum-cleaner hose. Those units =3D
usually run on 5 to 7 PSI produced by the turbine, and thus need quite a =
=3D
large hose to carry such low pressure to the spray gun. The =3D
turbine-driven HVLP guns have the highest transfer rate (percentage of =3D
medium that actually ends up on the target rather than as overspray =3D
mist) of any spray-gun. =3D20
If you don't already have them, be sure to install standard =3D
quick-disconnects on the compressor and gun and on both ends of the =3D
hose. You probably already know this, but install the female disconnect =
=3D
chucks on the compressor and on the spray-gun end of the air hose, and =3D
the male connectors on the spray gun itself and the other end of the air =
=3D
hose. The reason for this is that the female air chuck contains a =3D
shutoff valve and will not release air unless a male connector is =3D
attached, which is an advantage (and standard protocol) on the =3D
compressor and on the loose end of the air hose.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Phoenix Rising Farm on wed 22 jul 09
Shula dear:
With all things pneumatic, this is the rule:
increasing the INSIDE diameter of the hose will increase the VOLUME of
air (or gas) being delivered,
but not the pressure. Pressure is a function of your compressor, not the
hose.
Does your HVLP sprayer require more volume of air than your compressor
supplies with a 1/4 inch hose? A 3/8 hose? Then upgrade to 1/2 inch hose.
Other than that, same same.
I have air tools (large nailers and gigantic impact wrenches) that
require a specific CFM (cubic feet per minute) of air AT a specific
pressure (100-125 psi)
If I "starve" them by using too small a hose, they either do not work,
or work so poorly it is an exercise in futility to try to use them at all.
Other tools, such as ratchets and drills run happily on whatever air
supply I give them. They are not CFM dependent.
Generally, for a sprayer, a 3/8 hose will suffice. 1/2 inch is better
(more CFM or volume), but it's HEAVY to drag around all day. If you do not
plan on staying inside a spray booth for 8 hours, but are just spraying
glazes occasionally in one place, you would be ok with the added weight
of 1/2 inch hose.
And no... to answer the eternal question...in this case LENGTH DOES NOT
MATTER. Volume is volume, pressure is pressure.
Just take a moment and buy quick connect fittings for both ends of that
hose. That way, you can quickly uncouple the hose from either
compressor or sprayer and connect something else, like a tire inflator
or another tool. Buy a few sets of connectors (they're relatively
cheap), so that as your tool selection expands, you can make everything
work on the same hose,
and not have to putz around with teflon thread tape and wrenches every
time you go to do something. Any auto parts store can sell you those; HF
sells them too.
Hope that helps,
Wayne Seidl
Shula wrote:
> Dear Clay Buds,
>
> I recently bought an HVLP sprayer at Harbor Freight. My question is - doe=
s it make a difference what size hose I use to connect the sprayer to the c=
ompressor and if so, what size should I use and why?
>
> Thanks
>
> Shula
> Desert Hot Springs, California USA
>
>
| |
|
