Following is an article written by Bob Walls--great information! Thanks, Bob!
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I watched
a video review of the AK 3rd Gen acrylic paints where the reviewer
had issues with alcohol as a thinner. And I got comments regarding alcohol
gumming up airbrushes when added to acrylic paint, so I decided to test out the
thinner I use versus 91% alcohol. My “go to” thinner for acrylic paints is a
home brew suggested by posts on the internet and by club members. It is made of
66% distilled water (I have used tap water which worked), 25 percent 91%
alcohol and 10% Windex and 6-7 drops each of Glycerin and Glycol. Per comments
on the internet, the Glycerin, Glycol and Windex act as a flow improver, paint
retarder and lessen surface tension so the paint lays down better. Or they do
none of that, take your pick. I have used this home brew with every brand
Acrylic Hobby Paint I have ever purchased with excellent results. But that may
or may not be duplicated in your case due to airbrush type and PSI you use. The real reason for my
test was not to prove which Thinner is the best to use for airbrushing but to
see how they all react to different brands of paint, particularly 91% alcohol.
All the “thinners” tested are widely accepted as being “go to” thinners
by various posters/experts.
The
“experiment” was conducted by placing approximately the same amount of 5
different “thinners” in cups on my pallet and dropping 2 drops of each paint
into each cup. The first observation was after the paint drops had been sitting
in the thinners for 90 seconds. I call this my dispersion test to see if the
paint and thinner would mix without any stirring. I followed that with a test
where I stirred the paint and thinner with a toothpick with 4 or so stirs.
Finally, I used my finger and mixed the paints over my sink just before I
washed the pallet out for the next paint test.
Attached
is a PDF with the results (link below). I tested Mission Models, Vallejo Surface
Primer, Vallejo Air, Vallejo Color, Tamiya Color Acrylic XF, Badger Stynylrez
Primer, AK Surface Primer, Apple Barrel craft paint, Reaper Master Series,
Vallejo Metal Color and Vallejo Plata Liquido.
The
results varied slightly by paint except for the Vallejo Plata Liquido.
All the other acrylics liked distilled water and mixed well with it in all
tests. Some better than others but plain water will work to thin acrylic paint.
NOW IT MAY NOT spray well. I did not test that. The home brew came in second in
this test, third was water and Windex and alcohol and Tamiya thinner tied for
last with an exception or two. All the acrylic paints including Vallejo Metal
color will mix if you use some effort to stir the two for a while. The only
paint that hated this process was the Plata Liquido. It formed a solid film on water-based
thinners and Tamiya XF-20a. It was fine in alcohol.
Check out
the PDF to see the differences between brands and there are visible
differences. None of the acrylic paints (except the Plata Liquido) gummed
up to the point where you would have to break your airbrush down and clean it,
like seen in the review video of the AK 3rd Gen paint.
One thing
I noticed is that the Home Brew interacts with the paints. Even when NOT
stirred if given 5 minutes or so it mixed itself! Check out this video on the
Vallejo Metal Color which is easier to see due to the metal pigments moving and
swirling in the paint. It is obvious that something is going on. There was
no fan blowing and I did not mix the paint other than the 4 stirs with the
toothpick. But the paint is obviously mixing itself through reacting to the
home brew thinner.
Here is a
link showing the paint swirling in the home brew thinner.
At some
point I hope to pick up one bottle of the AK 3rd Gen paint and
perform the same test on it.
