Best primer for metal is duplicolor sandable primer. It is available in any auto parts store in the body repair section. It is made for sticking to metal and plastic. I have used it on resin as well. It has a nice ‘toothiness’ to it, and my paint has never lifted off the model.
Acrylic will work fine as long as you put on a durable topcoat. I recommend a clear gloss or matte sprak like Krlyon brand, available at any Wally World.
Acrylics are billed as being “less toxic” but that doesn’t mean the same as non-toxic. I prefer acrylics for the easy clean up, but I still use a spray booth and regulator.
Acrylics when properly cured (as opposed to merely dry) are very durable, provided you have properly prepped the surface first. A properly cleaned surface, free of mold release agents and fingertip oils can be all that is necessary, but an application of a good primer is recommended.
Check to see if your slots are styrene. I doubt it. Styrene is too brittle for use in the rough and tumble world of slots and RC models. They are most likely Polycarbonate, which requires a special paint. Polycarbonate paints are NOT compatible with styrene.
Any properly cured paint should handle washing with soap and water. Washing with solvents is inviting a new paint job!
Any spray primer will adhere to metal, so will Tamiya’s. Tamiya does not make a “metal” primer. All of their primers will adhere to metal.
On a properly cleaned surface, I don’t consider a primer necessary for acrylics—in fact, when I do prime, I generally use an acrylic paint. The exception is Model Master. If you must use them, a primer is definitely recommended.
As far as durability is concerned, some brands I have used are more physically fragile than others. MisterKit, in particular, produces a cured coating that is somewhat brittle, but resists alcohols. It is, however, attacked by mineral spirits! Odd stuff, even from my point of view…
I see, someone mentioned that alum needs to be primed with special primer or else the paint will not stick to it?Anyway when you say you prime with Acrylics, do you mist and blow air on it a few times, and then being to paint eventually?
Except for the occasional rattle can, I hand brush exclusively. I LOVE acrylics for covering large areas. It may take an extra coat versus the enamels, but acrylics are so thin that they do not “build up” and obscure detais like a couple of layers of enamel will.
Once past large surface areas like fuselages and wing surfaces, I go either way and prefer enamels for more minute details and drybrushing and highlighting.
ModelMaster enamels and acrylics are good. As well as Polly Scale acrylics. Vallejo are fantsastic, though pricy.
The only aluminum I know of that needs a special primer is Alclad II—definitely not an acrylic.
When I prime with acrylics, I just apply them as I would any other paint. As a general rule, airbrushing is best done in light coats, regardless of the paint used. Future is an exception: I get the best results with a relatively heavy coat, others do better with multiple mist coats.
Airbrushing is, after all, 70 percent practice, 20 percent science, and 30 percent art. Just do the math……
I have some brand new tamiya acrylics in their rattle cans. is there a way to use them on my AB?
I think Ross misunderstood that you meant painting ONTO aluminum, I would certainly prime before painting metals with any paint.
Decanting Tamiya sprays is relatively easy, but can be quite messy. The propellant can cause the decanted paint to do some pretty crazy things, so don’t be doing this in the kitchen, bathroom or living room. It can be very messy. I would use a cardboard box large enough to contain an out of control rattle can. It can be very messy. It does requires hardware store lacquer thinner for cleanup, but doesn’t really need to be thinned.
Did I mention that it can be really messy? [*-)]
Yes, I misunderstood. I’ve had success applying both Polly Scale and Tamiya to clean, fresh aluminum and brass metal of small parts. For anything larger than about half a square inch, I would recommend a primer intended for metal.
And not only is decanting aerosol paints messy, it’s dangerous. Stupidly dangerous in my opinion…but what do I know? I only worked in the R&D lab of an aerosol paint company…
Be aware that Tamiya’s spray cans are “synthetic lacquers”, not acrylics.
I had meant to add a link to the instructions for decanting rattle cans to my earlier post:
http://www.tamiyausa.com/articles/feature.php?article-id=301
It has a section on out-gassing of the propellant and has this warning which it wants you to read TWICE:
Ross,
Why is it dangerous to decant aerosol paints? I am not being sarcastic, and I greatly value your experience and opinions.
Thanks!
Chris
Because the solvents and propellants are generally flammable, and often the binder is also flammable, especially in its fluid form. The binder is also sticky. Under pressure, some of these materials can be considered explosive, or nearly so. Most of the methods of “decanting” an aerosol can involve concentrating a portion of the liquid in a small container by venting it through a plastic tube. This cold, concentrated liquid contains the propellant, usually a flammable hydrocarbon that is a gas under atmospheric pressure, but has been condensed into a liquid before being put into the can. If it boils off slowly and there is no source of ignition at hand, well and good. If it boils off rapidly, on the other hand, there are plenty of sources of ignition—I doubt if the typical work area has flash-resistant electrical connections. There is also a slight chance of static discharge, especially in the winter months.
If it ignites while being decanted, you get a fireball, possibly with shrapnel. Two foot diameter for one of the pint-sized cans, 4 to 6 for the larger ones. Quite spectacular. No saving throw.
While the chances of ignition are small, burns are very painful and take a long time to heal. Insurance companies and fire marshals take a dim view of things like this, too.
Accidents are called accidents because they are unexpected and rare. How rare is up to you.
Assuming this operation is done in a proper spray booth, the release of potentially toxic materials into your breathing air is minimal.
As a final note, aerosol paints are formulated and designed to be sprayed from the valve and spray head on the can, not from an airbrush. Why not just use the stuff as it was designed? Less messy and much safer. The only good reason I’ve ever seen to decant an aerosol paint (other than in a lab for research purposes) was if you need just a small amount for touch up work. In that case, less than a second spray into the cap is safer and provides all the touch up paint you could possibly need.
In short, sure you can do it and get away with it. But why bother? If you want to take unnecessary risks, buy a lottery ticket. Then if something unexpected and rare happens, it will make you happy.