QUestion regarding "delicate" paint--my finishes seem overly fragile

I'm new to airbrushing but I spent a pile of hours last Summer to practice with equipment and paint mixes.

I found that adding Windex brand window cleaner made my acrlyic paint adhesion fail. I switched to a retarding agent made by the paint maker. Now my paint coatings dry as hard as nails.

Citadelgrad87 wrote:

I have a Badger 200, probably 25 years old, throws down an amazing coat when I do my part. Since my return to modeling after 20 or so years off, I find Tamiya acrylics to be easy to mix, use, and spray. I use Tamiya's thinner, and mix to approx skim milk thickness. The paint coming out and laying down acts like it should. My issue is that my paint seems to be extremely delicate, to the point that I can rub it off with a finger, especially on pe parts, and tracks. After I posted a query in Armor, I now diligently wash the plastic parts in dishwashing liquid to get rid of any release agents. But on my Sherman, there are several areas, mostly PE areas, that have missing paint, is this unusual or the nature of the beast?   Thanks,   Bill

Bill,

I know this is gonna sound redundant but try putting a primer coat over your PE before you paint them. Primer coat helps the paint bite down harder making it harder to be scratched or rubbed off with normal handling. Another idea is to add a few drops of Future to your paint mix and brush it on after you primer coat PE parts and let it dry for about a day. Future will help insure paint dries hard and less resistant to chipping, peeling, scratching.

Hops this helps.

Air Master Modeler wrote:

Citadelgrad87 wrote: I have a Badger 200, probably 25 years old, throws down an amazing coat when I do my part. Since my return to modeling after 20 or so years off, I find Tamiya acrylics to be easy to mix, use, and spray. I use Tamiya's thinner, and mix to approx skim milk thickness. The paint coming out and laying down acts like it should. My issue is that my paint seems to be extremely delicate, to the point that I can rub it off with a finger, especially on pe parts, and tracks. After I posted a query in Armor, I now diligently wash the plastic parts in dishwashing liquid to get rid of any release agents. But on my Sherman, there are several areas, mostly PE areas, that have missing paint, is this unusual or the nature of the beast?   Thanks,   Bill Bill, I know this is gonna sound redundant but try putting a primer coat over your PE before you paint them. Primer coat helps the paint bite down harder making it harder to be scratched or rubbed off with normal handling. Another idea is to add a few drops of Future to your paint mix and brush it on after you primer coat PE parts and let it dry for about a day. Future will help insure paint dries hard and less resistant to chipping, peeling, scratching. Hops this helps.

Air Master,

 

That's what I get for taking a phone call while posting, this pesky work got in the way again.  I KNEW I forgot something:

The PE was primed, along with the model, with Tamiya grey surface primer for metal and plastic.

And that's why I posted the question, I am stumped.   

 

I recently switched to Games Workshop Spray Primer, I use thier Skull White Primer. Costs about the same as Tamiya's but you get a bigger can. It sprays finer, feels smoother, dries hard and faster than Tamiya's. You can look into it Games Workshop has a web site you can buy direct from and also Hobby Town carries it. Something to look into.

 http://www.games-workshop.com/gws//home.jsp?_requestid=181127

 

The very smooth, almost polished nature of some PE parts  can make it difficult for any paint to stick. The presence of skin oils on said parts can further add to the problem.

Give the PE parts a very light rub down with a  very fine grit wet and dry. Before painting, make sure the surface is clean. You can spray with Windex and rinse and allow to dry, and avoid handling those areas until painted. As an alternative, you can load up your airbrush with clean isopropyl or denatured alcohol and spray your model down and allow the alcohol to evaporate away before applying paint.

In general, though Tamiya acrylics touch dry very quickly (sometimes within seconds of application, your model is best left for at least 12 hours before handling. In the first few hours, though the paint may seem to be dry, it isn't cured. After about 12-24 hours it should be pretty well hardened.

What type of tracks are you painting? Vinyl tracks seem to repel most paints unless they are well cleaned beforehand and primed lightly with an automotive type primer. More recent flexible track types (eg. Tamiya's "glueable" tracks and Dragon's DS tracks) seem to take paint a lot better than their shiny smooth vinyl predecessors.

I have started priming all my models and figurines with duplicolor sandable primer.  It is designed for automotive use, and sticks to bare metal very well.  I also paint plastic minis, resin, and styrene.  It comes out of the can very fine, again is SANDABLE, and is only about $5 a can at most auto parts stores.  Comes in several colors too!
Hope this helps!

Chris

The problem with PE is that it has a "smooth" surface that enamels and acrylics can't get a grip on.  I've seen two ways to get around this.  I dip the PE part into vinegar for a minute or two - the vinegar, being a mild acid will etch the surface, giving the paint something to hold to.  The silver colored PE doesn't seem to react to vinegar as well.  In that case I lay the PE fret on a piece of glass and gently sand both sides w/1000 or finer wet/dry sandpaper prior to removing the parts. HTH