A Question for Tamiya Acrylic Paint Experts


IronBeltKen

Lazy Daydreamer
Hi all, my current project is to replicate a B&O F7A in the later Enchantment Blue/yellow trim paint scheme, the same colors used by its parent company C&O. The time period is 1969-72, so the paint during this period would appear faded from several years of sun and rain.

Ever since Floquil/Pollyscale ceased to exist, I have used a homegrown mixture Tamiya Royal Blue (X-3) and Red (X-7) to achieve a color that closely resembles Enchantment Blue since it airbrushes nicely and dries in a semi-gloss matte finish that is perfect for applying decals. Every loco that I've painted using this method is initially deep blue, so I need to spray repeated light washes of Tamiya Flat White (XF-2) over it until the color looks adequately faded.

What I've discovered is that, while the above method works like a charm on factory-painted shells, I've often had problems on the Tamiya paint where the white wash mixes with the underlying color instead of sitting on top of it - giving it an unwanted greenish tint. I'm guessing this is due to my using the Tamiya brand thinner solution which attacks the blue paint. My earlier solution to this problem was to simply mix denser ratios of white with the thinner in order to use fewer coats and allow less time for the wet thinner to attack the blue. But this has its own problems, like leaving subtle splotches that are invisible to the human eye but glaringly obvious in photographs.

What I want to do is - unlike when applying regular paint in thin, quick drying micro coats - is put multiple layers of white wash that are fully wet with no discernable individual splashes, and let these dry for ~5 minutes before applying subsequent coats. Since doing this with alcohol-thinned paint has given me unwanted mixing, I want to try this method using plain water [with a drop of dishwashing detergent added] as my thinning media. I know that acrylic paints thinned with water don't "atomize" very well for airbrushing, but remember, my goal is to get to totally wet, slower-drying layers onto the dark blue paint where the water will [hopefully] not attack the blue as the alcohol does.

I want to know if any of you have ever tried this, and if so, what results did you get?
 
Although I wouldn't quite characterize myself as a Tamiya paint "expert," I have been using their paints and other hobby supplies for...geez close to thirty years now, I think. However, most of that has been on non-railroad models, i.e. planes, tanks, ships.

First off, I haven't done exactly what you are asking about. I have thinned acrylics with distilled water in the past, but I find myself going back to bona fide thinner most of the time for the atomization issues you mention. Off the top of my head, I can't recall the results with Tamiya paint and water; I've probably done it, but just many years ago.

But a couple thoughts:

1) How long are you waiting for the base blue coat to dry before spraying the white? With your original method of white paint and airbrush thinner, I would wait at least 24 hours, and 48+ hours would probably be better.

2) Do you consider the white top coats to be "weathering" coats? In other words, are you using the white coats to simulate sun/rain/time faded paint and wear, or are you trying to more closely replicate the original factory paint color tone?

If it's the latter, I would probably try to lighten the original mix of X-3 and X-7 by adding gloss white or something similar to get your desired shade as a base coat.

However, if it's the former (i.e. you consider it weathering), I would actually seal the base coat before spraying the white coats on top. Generally speaking, weathering is applied on top of a seal coat. Yes, it takes longer, but it will ensure there's no interaction with your previous coats of paint.

There are lots of personal preferences out there, and I'm not suggesting this is the only way to do it, but in general the order of paint coats for plastic models is as follows:

-Primer, if needed (I don't often prime, I use it mostly before metallic paint coats, gloss paint schemes like airliners, or if I want a smoother or more adhesive base layer)
-Base coat
-Gloss seal coat, if you're adding decals. This is because decals apply best to a glossy surface.
-Another gloss seal coat over the decals. This helps the decals blend in, by being sandwiched between two gloss seal coats.
-Weathering with paints, washes, etc.
-Top seal coat. Either gloss or matte depending on what you're modeling.

With 24-48 hours between each of those, yeah, it's not gonna be done in one night.

In your case, I would suggest a test run (on scrap or some leftover styrene) of letting the blue coat dry for 48+ hours, then trying the white coats. Or even better, seal it with a gloss top coat, and letting that dry completely, before the white. Just make sure you get gloss or flat coat sprays that are compatible with acrylic paints. There are some out there that are intended for enamels, which can mess up acrylic base coats and vice-versa. In my experience, Tamiya gloss coat in the spray can (TS-13) works well with their paints.
 
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Thank you for the detailed reply!

1) How long are you waiting for the base blue coat to dry before spraying the white? With your original method of white paint and airbrush thinner, I would wait at least 24 hours, and 48+ hours would probably be better.
I applied the base paint to the model over two weeks ago, should be pretty well cured by now I would think...

2) Do you consider the white top coats to be "weathering" coats? In other words, are you using the white coats to simulate sun/rain/time faded paint and wear, or are you trying to more closely replicate the original factory paint color tone?

... if it's the former (i.e. you consider it weathering), I would actually seal the base coat before spraying the white coats on top. Generally speaking, weathering is applied on top of a seal coat. Yes, it takes longer, but it will ensure there's no interaction with your previous coats of paint.
Hmmm, hadn't actually considered the sealing option...if I can do that without compromising the details too much, I may do that.

There are lots of personal preferences out there, and I'm not suggesting this is the only way to do it, but in general the order of paint coats for plastic models is as follows:

-Primer, if needed (I don't often prime, I use it mostly before metallic paint coats, gloss paint schemes like airliners, or if I want a smoother or more adhesive base layer)
-Base coat
-Gloss seal coat, if you're adding decals. This is because decals apply best to a glossy surface.

I only use primer when I have sharply contrasting underlying colors of plastic, to ensure that the applied color will be consistent. As for the initial gloss coat over the base paint, I've found the finish of Tamiya gloss paints to be very decal-friendly - after Micro-Sol treatment, I typically cannot tell the decal film apart from the bare paint.

-Another gloss seal coat over the decals. This helps the decals blend in, by being sandwiched between two gloss seal coats.
I might do that for the reason indicated above (keep the base paint from mixing with the weathering paint).

-Weathering with paints, washes, etc.
-Top seal coat. Either gloss or matte depending on what you're modeling.
I always use the Tamiya flat white or light gray mix, and they they dry with nice flat texture - never had to use any fixative for that, it's pretty permanent.

In your case, I would suggest a test run (on scrap or some leftover styrene) of letting the blue coat dry for 48+ hours, then trying the white coats. Or even better, seal it with a gloss top coat, and letting that dry completely, before the white. Just make sure you get gloss or flat coat sprays that are compatible with acrylic paints. There are some out there that are intended for enamels, which can mess up acrylic base coats and vice-versa. In my experience, Tamiya gloss coat in the spray can (TS-13) works well with their paints.
I went ahead and airbrushed 3 of my "junk" shells with the same home-mixed color of dark blue that's on my subject F-unit, and I'll experiment with those this weekend using different thinning media - and choose the approach that gives me the best result. 👍
 
I don't use the Tamiya paint, but use acrylic paint. After I paint a model I gloss coat about 2-3 coats for decaling. After that gloss coat again to hide the "ghost" of the decals. Then dull the car down with dull coat. A few coats will fade the paint. You could add a drop of flat white to the dull coat if they don't make a dust color. I don't ever thin my paint I use different tips and pressure to get the effect I want. If your using alcohol, use 70% . A lot of these cars were BN.
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