Help! How can I paint this styrofoam model to look like the image?

[CadetJames]

How to get such a high quality finish?

Starting with Plain white styrofoam that the kit came in and ending with the below effect.

 

[Fluburtur]

Well, sandpaper and a paintbrush is usually the way to go.

 

[FDS]

I would be very wary of painting it. You will need to fly it line of sight at times, making it totally blend in with the UK sky is not very helpful for that.
If you really must make it invisible to the naked eye and near impossible to position in the sky then use water based acrylic paints, do not use spray paints, as they melt the foam. That one has probably been painted using an airbrush and water based paint. You might be able to use a large, soft paintbrush and acrylic craft paint.
Watch out for getting paint all over the hinges of any control surfaces. You shouldn’t sand paper polystyrene type foams, as they are super soft and scratch easily. If you need to key it for paint use a fine Scotchbrite abrasive pad, check eBay for those.

 

[quorneng]

As FDS says you have to decide if you want it to look like the real thing (and they are painted that colour for a reason) or something that you can see easily in a wide range of conditions and circumstances.
If it flies well and you get to fly it regularly it wont be long before you end up in a 'difficult visibility' situation. The feeling of hopelessness when you loose sight of model in the air is not to be recommended.
Its a sort of catch 22 situation.
Keep low(ish) and easily in sight but then any 'pilot error' and the ground is less than a second away.
Keep high (400 ft ) and the ground takes longer to 'arrive' but the physical distance between you and plane means the chances of loosing sight of it are that much greater.

 

[FDS]

OP plans to have GPS autonomous flight, but you still have to launch and land, both places where depth and orient perception are important.

 

[clolsonus]

I have had some success painting this type of model with rattle can paint from the local hardware store ... but you have to be very careful!

The propellant in the spray can eats away at the foam and makes a big globby mess of the surface. So what I will do is just lightly dust the surface from a long ways away 18-24" maybe. Then I'll do it again, and again. The goal is to get a smattering of paint hitting the surface but from far enough away so the propellant dissipates (mostly). After 4-5 light dustings, enough spatterings of paint start joining together to protect the underlying foam surface. Then you can hit it with a bit thicker coat of spray. It is really hard to be patient enough and get enough dusting coats in, but when you do it carefully, the result can turn out very nice.

I will typically paint the wing tips and tail tips and leave most of the model unfinished white.

There are lots of types of paint (and I'm not a paint expert) so maybe you can find something that works better and is safer with foam. For me, the easiest way to get a variety of colors and get the job done quick is to run up to the local hardware store and grab a rattle can of something.

For the skywalker below the wings and vertical stab turned out perfect, but I got impatient on the horizontal stab, so especially the moving elevator got all bubbled up and globby ... eventually it dried enough so I could lay down a few more coats of paint and it wasn't too noticeable, but ugh, I notice it every time I look at it. The model aero polaris turned out really nice (I got an all white unpainted pre-production version.) Adding some electrical tape to trim the edges seemed to be a nice way to finish off the seams.

 

[Janicer]

Hey, I think it takes a lot of patience to get that quality. To me, I really like doing things with my own hands. So not to waste your time and nerves. The best solution is to use the best glue for styrofoam. It's the only thing I use because еhe thick consistency of the glue gives you a quick bond with good holding power, so you aren’t required to sit there, holding two pieces together for an hour.

 

[The Hangar]

I have had some success painting this type of model with rattle can paint from the local hardware store ... but you have to be very careful!

The propellant in the spray can eats away at the foam and makes a big globby mess of the surface. So what I will do is just lightly dust the surface from a long ways away 18-24" maybe. Then I'll do it again, and again. The goal is to get a smattering of paint hitting the surface but from far enough away so the propellant dissipates (mostly). After 4-5 light dustings, enough spatterings of paint start joining together to protect the underlying foam surface. Then you can hit it with a bit thicker coat of spray. It is really hard to be patient enough and get enough dusting coats in, but when you do it carefully, the result can turn out very nice.

I will typically paint the wing tips and tail tips and leave most of the model unfinished white.

There are lots of types of paint (and I'm not a paint expert) so maybe you can find something that works better and is safer with foam. For me, the easiest way to get a variety of colors and get the job done quick is to run up to the local hardware store and grab a rattle can of something.

For the skywalker below the wings and vertical stab turned out perfect, but I got impatient on the horizontal stab, so especially the moving elevator got all bubbled up and globby ... eventually it dried enough so I could lay down a few more coats of paint and it wasn't too noticeable, but ugh, I notice it every time I look at it. The model aero polaris turned out really nice (I got an all white unpainted pre-production version.) Adding some electrical tape to trim the edges seemed to be a nice way to finish off the seams.



View attachment 151058 View attachment 151059

I really like the last plane! I should make one out of foam board sometime!

 

[uggymoo]

I have a lot of luck with eggshell house paint and 4 inch foam rollers . Home Depot has 8 oz sample size in any color you want . Just keep the roller very dry and do 2 to 3 very thin coats

 

[PsyBorg]

I use Krylon sanding primer after coating all exposed foam edges with white Gorilla wood glue. Like @clolsonus said, you mist it from at least 12 inches away and let it dry then keep repeating until the primer is solid and even. Light sand it and then rock on with what ever paint you want to use.

I use the pink spackle with the fiber in it to smooth out joined areas. Sand that down to a finished surface. Then coat that with the white gorilla glue which makes it more rubbery and not so brittle before priming.