Build tech- foam models
Uploaded files:I’m building a foam space shuttle. Typical tricky glues and paints which can be used. I already know epoxy is ok, CA, plastic model cement is not ( see Porta John build)
I didn’t need to paint the Porta John. I know the paint needs to be enamel but I wanted to try what I have. Oh boy. The clear coat was the worst. It’s melting the foam. Always test in a scrape piece.
Solvents in most rattle can paints will eat styrenes. Testors spray enamel paints work on polystyrene plastics without damaging them.
You're better off, if you really want to paint that foam of the Space Shuttle, to paint it with water-based acrylic airbrush paints like Createx. For clear coat, the Createx 4050 Gloss UVLS Clear is an acrylic–aliphatic polyurethane. Yeah, I know, the bank will call of you buy an airbrush.
Uploaded files:I tested the testor enamel paint, black n white. No problem
I ordered enamel clear spray can. Not good!
the lesson is test on scrap foam. I watched a YouTube video on how to use rattle cans on foam. Light coats to allow propellant to evaporate . It’s the propellant melting the foam
the clear coat will need to be aqueous based
Quote from Zielijo1 on May 1, 2023, 12:33 pmI tested the testor enamel paint, black n white. No problem
I ordered enamel clear spray can. Not good!
the lesson is test on scrap foam. I watched a YouTube video on how to use rattle cans on foam. Light coats to allow propellant to evaporate . It’s the propellant melting the foam
the clear coat will need to be aqueous based
If you are painting it with enamel, you do NOT want to use a clear lacquer clear coat. That pretty much leaves your with two choices:
- Don't clear coat it, or …
- Use a clear urethane spray, or …
- Use a clear acrylic stray.
If you elect the latter two in aerosol rattle cans, you'll still need to do some test sprays to assure yourself that the VOCs do not dissolve the plastic. For a small rocket like yours is, the airbrush and Createx 4050 Clear Gloss is your best bet.
For a small model like that you could also use a brush-on clear coat. It'll be a little heavier, but not enough to matter. As a bonus, it might be more protective in return. I would use Mod Podge, available basically anywhere craft supplies are, but there are a bunch of options. If you're confident in the paint sprays not eating the foam then you can do it afterward. But you can also use a coat or two of Mod Podge before painting to seal the foam, and then not worry about using whatever paints and clear coats you want. I do this often in building miniatures wargaming terrain (like model railroading, but with toy soldiers & rules instead of trains & electricity).
For sure still test out the whole process on a scrap piece though, e.g., to make sure you're coating thickly enough.
Quote from tjkopena on May 7, 2023, 8:19 amFor a small model like that you could also use a brush-on clear coat. It'll be a little heavier, but not enough to matter. As a bonus, it might be more protective in return. I would use Mod Podge, available basically anywhere craft supplies are, but there are a bunch of options. If you're confident in the paint sprays not eating the foam then you can do it afterward. But you can also use a coat or two of Mod Podge before painting to seal the foam, and then not worry about using whatever paints and clear coats you want. I do this often in building miniatures wargaming terrain (like model railroading, but with toy soldiers & rules instead of trains & electricity).
For sure still test out the whole process on a scrap piece though, e.g., to make sure you're coating thickly enough.
Can this Mod Lodge be used in an air brush? Can it be thinned and, if so, with what?