Re: Flat Black

John Sykes III

I think that, all in all, the most important factor is the evaporation rate of the solvent.  Acetone evaporates the fastest.  I've had the paint dry before it hits the surface being painted with acetone as a airbrush thinner.  Lacquer thinner is somewhat slower (depending on the VOC % - higher VOC = faster drying).  Toluene and zylenes are about the same (except toluene attacks plastics more - it was the main ingredient of the old Testors plastic cement) and Butyl Cellosolve* (2-butoxyethanol) is the slowest.  The key is the % of aromatics (VOCs).  I also have Naptha VM&P but have not used it.  I am just talking about lacquers here (old Floquil and ScaleCoat I).  A lot of the personal preferences with lacquers is due to the heat and humidity where they are being used.  I live in Florida (hot and humid) so that colors my preferences.

With enamels (e.g. ScaleCoat II), again the main issue is the VOC content of the paint thinner (a/k/a mineral spirits, a/k/a etc., etc.).  "Low odor" paint thinners have lower aromatics/VOC concentrations, hence lower solvent abilities - not so good for cleaning brushes (air or bristle).  Turpentine was/is a whole different animal (I don't use it, but many artists still do with oil paints) based on turpenes (e.g. phenols).  I've used lacquer thinner for weathering with SCII flats, very successfully I might say, because when mixed with paint at a 90:10 ratio (thinner to paint) it dries in seconds, which is what I want when weathering, so I can layer dust, grime, rust, etc. in one session.

Note that, as is the case with Diosol, a lot of the above solvents can be mixed to control their solvent ability and drying rate.

*  A mix of 5-10% Butyl Cellosolve & in isopropyl alcohol (91%) makes a good paint stripper (a/k/a Chameleon or Wash Away), but not for use on ABS plastic.  4-6% Butyl Cellosolve in water with a tiny bit of surfactant makes a good decal setting solution (original Hobsco Solvaset or Champ formula).  The new Walthers Solvaset uses a completely different chemistry.  Butyl Cellosolve is a rare bird in that it is soluble in both organics and water.

-- John

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