I recently bought a moisture trap for my compressor and tried painting
while it was raining outside. I still get a paint blob after a few
hours of painting. What's the deal with this? the moisture still formed
after where the trap was installed.
That's interesting -- I had a moisture filter/trap that fit right on the
compressor and it worked fine and I never had a problem with water in my
paint. I now use a compressor with a 2.5 gal. tank and the trap is on a hose
that is about 10 feet long. I never see any moisture at all in the trap when
using the tank compressor -- most of the moisture will condense in the tank.
I don't know what kind of paint is being used but if it is acrylic it has a
tendency to dry in the airbrush if you let it set too long. Some older type
airbrushes have clogging problems with acrylics due to the design of the
nozzle. I had this "blobbing" problem with my Badger 150 and acrylic paint.
I got a new airbrush with the cone type nozzle and the problem went away. If
you have to let the brush sit for a while with paint in it it's a good idea
to submerge the tip in a bowl of water to help keep the paint from setting
Actually, a trap works better if it is a little ways from the
compressor. That is, have a little bit of line between the compressor
and the trap. A section of metal pipe is ideal. The air has to cool in
order for the water to condense, so the cooler the air entering the trap
the better. If the trap is right on the compressor the air may still be
too hot, especially if it is a tankless compressor or one with a very
Nothing better than redundancy, I have a water/moisture filter on the first
hose that leads out of the compressor and a second filter (Paasche) about a
foot from the airbrush itself, second hose - all together about 12 feet of
hose.. Have had this rig for the past 15 plus years and have yet to find
any water blobs spattering on my models. Water blobs are really a pain in
the rectum ("ass" for y'all on the west coast). I have an old, very old,
Penncrest diaphragm compressor that I inherited when my Dad passed away
back in 1977. He'd had it for about 10 years before he passed on. It's a
little cantankerous and has to be either kicked or jolted and turned on and
off a few times before it starts to work. But hey, if it works, it works
and why spend money for a new one. I guess I keep it mostly for
sentimental reasons. Reminds me of him, he was quite a guy, and my best
role model (no pun intended).
However, if you want to spend a few more bucks, get yourself a canister of
compressed Co2 , somewhat like the canister that dispense soft drink found
in most restaurants. There are a few members of the modeling club I belong
to that have this type of rig and to date, they all say that they don't
even have to think of moisture/water. The only problem I see there is
having to get the canister refilled after several models.
Depending on compressor/moisture trap, many require occasional draining.
Those intended for a regular tanked type compressor and attached at the tank
shouldn't need this. But, the inline filters that fit your airbrush hose,
definitely need an occasional draining by opening the thumbscrew. I do this
every time I pause painting for a minute. It may not drain anything every
time, but I figure every time it does it's a splatter I saved from
happening. If condensation is particularly bad that day, in a long session
I may even reverse the hose on the compressor, lay it flat, and let it blow
clean the hose between the compressor and filter.
Filters are also directional, be sure it's installed properly or it does
little more than reduce air flow. If it's an inline filter, it should be
close to airbrush end of hose, back just far enough to be out of the way.
Painting when it's raining more than a quick shower or just before/after a
rain or wet snow isn't the best. Odds are high that the issue isn't your
trap failing, more that you're sucking more moisture out of the damp air
than it can remove. If your doing the garage/porch/outdoor type painting,
there's not a lot you can do to overcome a crappy day. Indoors you can
however control the room a bit with a dehumidifier. Takes a bit to have a
drying effect, but on a cooler day a space heater can do the same if you're
careful not to kick up too much dust with it. Doing this with a heater
actually takes a bit of trial/error since temperature in the room can affect
the condensation. And, the McDonalds "hot coffee" type idiot warning: Turn
off the heater before painting, 1500watt heat element in heater +
aerosolized paint thinner = possible big boom.
The design of these filters is to keep up with condensation created by the
compression in the system. They don't do much to actually dry wet air.
There's an item called a tank dryer used in some industrial applications
that can do that at prohibitive costs, and filters help some, but it's not
really their intent to dehumidify. Mild humidity they do ok, but bad
humidity you need to dry the air going into the compressor to not get some
moisture coming out.
You state "paint blob", moisture does look much like that, but a close look
can usually tell it's water splatter rather than paint. Especially once dry
you can see a puddle was there from the flow lines, but there's no dried
paint puddle. If it is actually paint, there's a lot of factors to
consider. Mix ratio, proper type of thinner, air pressure, poor brush
cleaning, sedimentation in the paint cup, impurities in mixed paint, all
seals and washers in place, etc etc.
Honestly, I think for a short time I used more brake fluid to strip paint
than paint to paint parts trying to figure out why this or that happened
with my airbrush when I got it. Been using one for years now, still keep a
tub of brake fluid and some latex gloves up on the shelf for when *it
happens. Rest assured that it'll never be some odd little detail piece that
never gets seen, when it happens it will always be the topmost, frontmost
part that will most display your error on the finished model and most likely
on your final finishing coat. I'm in a valley with 2 rivers within a mile,
3 lakes within 5, and lots of wetlands nearby, it's humid here quite often,
I spend a lot of time "preparing the air" before I even turn on the
compressor. I never post here, not really into all the military building
stuff that's prominent here, but damn, since it's too damp here today to
even try airbrushing anything but little bits I could as easily brush so far
today, and I'm feeling too damned lazy for everything else, figured I'd
share the pain.
Where is your compressor located? Is it in the same room as you work
in. Or is it in a remote location. If your air compressor is in a
cooler location, say a cold garage and you are pumping air into a warm
basement, the lines will condensate moisture as the air travels from
the cold air into the warm house. A moisture trap should be mounted as
close to end of the line as possible to do the most good. My
recommendation is purge your whole system with isopropal alcohol.
Drain down your air tank if equiped, pour in about a cup of alcohol,
fire up the compressor and immediately open up the line at the far end,
hopefully you are able to have that end outside. Remember NO SMOKING
or OPEN FLAMES!!! This will flush out the water already trapped in the
system. If your compressor is drawing cold air, you will want to do
this a couple times a year and also purge/drain the system at least
weekly. If you don't have an air tank, pour alcohol into the line at
the compressor end, Hookup the line and blow the line clear. You may
have to do this twice. The problem may not be water, it could be oil,
either way this should help solve your problem. Not knowing the
specifics it is the best advice I can give.
The Badger 155 is an excellent airbrush and should be able to handle just
about any type of paint. Can you tell if your blobs are due to droplets of
water or lumps of paint? A good filter/trap should be able to handle the job
coming straight off of the small compressor. If its not efficient you might
need to do as others have suggested and add a bit of hose between it and the
compressor or even better add a second filter. If you are using the color
cup you should periodically flush it and the airbrush. Another thing -- I
have found that Tamiya acrylics can be problematic -- when exposed to air
they have a tendency to gel and clump at times.
Usually when it starts spurting out funny sounds i remove the hose and
typically it will spray a fine mist of water through the hose. So, yes,
it is a paintblob caused by water mixing within the paint.
DO NOT PUT BRAKE FLUID THROUGH YOUR AIRBRUSH. I keep a tub handy at the
paint table to fix errors as in soaking the part for a bit in it and using
qtips and a soft toothbrush to scrub the paint off the plastic followed by
soap and water wash. While it'll strip even many year old paint, it works
fast on still tacky paint. It may be safe to put through your airbrush, has
to be less caustic than some paints I've used, but I'd never do so myself
nor suggest it, and there's no reason. Big point of the brake fluid mention
was just that you've really got to be as prepared to fix an error as it is
easy to make one.
There's very few paints I can use straight from the jar. My Badger is old
enough they didn't stamp model on it, and I've long misplaced the manual,
but it's similar to one of the 200 models and works like new. I paint with
everything enamel, acrylic, nail polish thinned with acetone, auto paints,
etc. Some it's just a few drops, but most I do thin. The exception being
testors metalizers and some auto paint I get from a shop that does custom
rattle cans but will sell me a one off 2 oz. bottle from their mixed paints
which are already thinned for the rattle can. This however truly is a "what
works for you" thing. Beyond just flow through the airbrush, different work
habits, light spray, heavy spray, etc. make a difference. I may actually
thin different for different coats of paint, thinner for mist coats, thicker
for wet coats. Check for a water in oil reaction by mixing a few drops of
paint, but most acrylics thin fine with alcohol. That said, head/needle
size matters, a large head can pass thicker paint, a smaller head needs
thinner paint. Air pressure matters, more pressure can pass heavier paint.
Lower pressures, smaller head, thinner paint. How thin, there's tons of
factors that go into that, but I heard someone once say the consistency of
whole milk as a base. I usually find that just a touch thin, but it's a
good reference point. I hear a lot of folks say they use Future acrylic
straight from the bottle, I have to thin it myself or the flow pulsates
badly and it tends to plug the head and start to spatter.
As for spare hose. If it's a bolt on type filter, it does go on the
compressor, but the inline filters actually require you cut your pretty new
braided hose and insert at that point.
I'm kind of thinking you just picked a bad day to paint, too humid. I'd
still suggest eventually getting an inline filter. As someone else stated,
on a tankless compressor, the air is still hot at that point it hits the
filter. As it cools going down the air hose, moisture can still form. I've
got a diaphram compressor, tankless of course. I used to run a filter at
the compressor, and one inline. I now just run the inline and notice little
difference other than a bit better air pressure as long as I keep the inline