Never sprayed with HVLP before but just purchased an
inexpensive "mini" gun.
Its rated 3.5 to 6.0 CFM at 45 to 60psi.
120ml plastic cup with 0.8mm nozzle.
I now need to purchase a compressor and wonder what is the smallest
I can get away with.
Only will be spraying lacquer on small decorative boxes, no big
cabinet jobs or anything like.
Any advice would be appreciated.
On Feb 21, 6:22 pm, firstname.lastname@example.org wrote:
Thanks, I know the specs are there but guess my question should have
been, because I'm only
spraying small pieces, can I go with a compressor on the small side of
the specs and
still work ok? I want light weight and portability. Then again, I
don't want the thing to run continuously.
How many gallons should the tank hold for small jobs like this?
Princess auto has a "pancake" style for $144, 5CFM at 40psi, 5 gal
Good advice, but be aware that both sides of this equation are prone
to inaccuracy. The compressor you buy may or may not have the "stuff"
it says it has, and the gun manufacturers (especially the Chiawanese
makers) all all over the place with their specs.
Probably. If you are spraying really small stuff, you may not be in
bad shape with that machine. I am thinking that you have that little
bitty gun, and they don't take as large a draw as you might think.
Besides, the recovery on that compressor should be fairly quick.
If you haven't sprayed with a setup like this before, you will find
that the compressor will run frequently when the two items are this
closely matched for draw and supply of air. There is an art to that;
you can help yourself by opening the electronic off/on regulator box
and turning the set screw all the way to one side or another to
increase the pressure as high as you can to make the compressor kick
on at higher temps. This will help keep the fluctuations of pressure
to the gun as low as possible.
When spraying with compressed air, you MUST have a moisture trap,
and hopefully a particulate trap as well. Buy a hose for spraying,
and use it only for that to keep contaminates out of your spray rig.
BTW, that's a pretty tiny little aircap. I hope you aren't spraying
anything more than really thinned products from it. Although it will
work with proper thinning and pressure, that's right at airbrush size,
not really made for wood finishing.
SFWIW, there are some simple things you can do to help keep water out of
your compressed air supply by trying to keep the air as cold as possible
during the compression process.
1) A 2 stage compressor is worth the added cost.
2) The larger the storage reservoir (tank), the colder the air which allows
the condensate to drop to the bottom of the tank.
3) Use as large a hose as possible since this will reduce pressure drop,
thus reducing compressor running time.
4 ) Plumbing.
Forcing the compressed air to change directions will provide a means for
moisture to drop out of the air stream.
Come out of the storage vessel with a connection to the "side" of a pipe tee
with and the "runs" of the tee vertical.
Connect a large nipple and a petcock to the "BOTTOM" side of the tee. (This
is where you will collect and drain condensate)
Connect a 6"-12"nipple"UP" side of the tee, followed by two (2) street ells
which creates a 180 degree turn, thus allowing the outlet to point down.
The larger the pipes, the better, but at least 1" minimum.
Connect the hose to this last port.
The above is a simple, but very effective condensate trap.
As long as you remember that compressing air creates heat and hot air holds
more moisture than cold air, the easier it becomes to reduce the condensate
I think OP is going for the "cheap" way into spraying. I am sure he
is looking at one of those oiless compressor setups that are out there
at that price point.
I didn't want to put your comment in about the hose adding more volume
as I was sure someone would come along and figure out the length and
internal diameter of the hose, then the cubic inches that would add.
Then of course others would come along and talk about leaky fittings,
etc., that would marginalize the hose volume.
Last year I sprayed an automotive style finish (not buffed, just the
urethane enamel) on a large group of exterior doors. I had to spray
in their warehouse (they sell doors) as they didn't want the doors to
leave the premises. From some reason, my HVLP system and I just
couldn't get he mix right no matter how hard I tried. I never did
figure out what went wrong, but don't spray enough of that particular
enamel to work out the kinks.
So with me at odds with the Fuji, I went home and got my Sharpe
knockoff HVLP and set that up to spray. That gun will spray anything.
But I worked my 4 horse compressor to death. It got so hot it was
throwing the breaker in the warehouse every 10 minutes or so. Then
the reset button on the machine kept tripping if the breaker didn't.
That day SUCKED.
Next day: came with 400 feet of 3/8" i.d. pneumatic hose and put
something similar to this in the chain just before my spray hose:
Problem solved. The 400' of hose did the trick.
I was able to screw the regulator/water filter unit on the wall for
stability. (Nope - didn't put anything in the oiler side!)
You are too damn industrious, Lew. If I worked out of a shop all the
time, I would use your system. Maybe...
But that little gizmo (and its relations) above even drains itself
when the pressure goes off, and it works great. Screw it on a wall
stud or piece of wood and you are installed!
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