In recent months I am seeing more and more outstanding looking structures made with a 3D printer. I recently saw one on ebay that I thought was a completed freight depot that was exceptionally well done but upon further examination, I realized the seller was offering an unpainted structure in a few sections. Still I was impressed enough to have an interest in buying one but I have no experience painting such a structure and would like some advice from someone who has painted these in the past.
For starters, should I start with a light coating of spray primer? My main concern with these structures is how well will the paint adhere. My second question is what type of paint should be used. Obviously, since the structure is pre-assembled, it will have to be hand painted. Will acrylic paints work or should I opt for an oil based paint.
Okay, there’s a major factor here. Are these structures plastic or resin?
I think regardless of what you do, I would sand the exterior surface well with high grit sandpaper (320 or 440, possibly higher). Not sure about priming. For the second question, based on what I saw from looking around on the internet, acrylic paint should work just fine.
As mentioned, sand as necessary and then I wash the model parts with Dawn dish soap and let dry. After that I paint with a quality paint designed for use on plastic. If I have any particular concerns, I’ll prime it first.
3-D printing doesn’t require a parting agent, so cleaning with Dawn is not as necessary as with molded parts.
Use a good etching primer for plastic. Any topcoat will then stick properly. Sanding is as much to level out the little ‘step’ ridges as to roughen the surface for adhesion.
And if it’s resin, then sanding is almost entirely unnecessary to hide the print lines.