Help - hand brushing with acrylics

Actually, Jesse, neither have I—but some have, ergo my caveat.

The reason an enamel primer "helps" acrylic adhesion is that the primer is more aggressive to the plastic surface—has more bite, as they say. The acrylic bonds with the enamel because the primer surface was designed (yes, it actually was) to provide a good bond with an overlying coating. Enamels are also more forgiving of surface contamination by skin oil and release agents, as well as plasticizers because these contaminants are soluble in the solvents used in enamels. Even alcohol solvent systems such as Tamiya and Gunze are much less tolerant.

However, using an enamel primer seems to negate much of the advantages of using acrylics, to my mind. For that matter, I use one of Tamiya's flat light gray colors as my primer for almost everything.

I've never had a problem with lifting during second coating of Tamiya Acrylics.  I usually wait about an hour before applying a second coat.  I also prime my model with an enamel or lacquer based primer.  I've found that the primer greatly helps acrylic adhesion.

Jesse

The keys to good adhesion with acrylics of any brand are a very clean surface and proper curing. Simple Green and Windex are excellent for cleaning plastic surfaces to receive acrylic paint. Rinse thoroughly and wipe down with alcohol, paint when the alcohol has evaporated (use 90% isopropyl or ethyl/denatured alcohol.)

For hand brushing, which produces a thicker dried film, allow 24 hours between major coats. 

Howdy,

Brush painting with Tamiya Acrylics is a lot different from brush painting with enamels.  Here are some tips:

1. Always end your brush stroke in an area already wet with paint.  In other words, your brush stroke should start in an unpainted area and end in a wet, painted area.
2. Try dipping your brush tip in Tamiya's thinner before dipping the brush into the paint.  This will help release the paint from the brush and stop it from clumping in the bristles.  I dip my brush in thinner about once every two times I dip the brush into paint.
3. Use Tamiya's thinner with Tamiya's paint.  I find it works the best.
4. Try to not to go over the same area more than two times when the paint is wet.
5. Allow about an hour between applying coats.
6. Darker colors may require two coats.  Lighter colors may require about 3.
7. Never paint directly from the container.  Transfer the paint to a palette.
8. Occasionally add thinner to the paint on the palette as it dries.

The acrylics have a shorter working time then enamels which causes some people to have problems with brush painting.  It just takes a little bit of practice.  There is an article called "Brush-Painting Basics" by Matthew Usher.  It's available in the Kalmbach book "Paint and Weather Scale Models".  There's also a free article here: http://finescale.com/fsm/objects/pdf/basicsofbrushpainting.pdf

Hope this helps.

Jesse