Marbling

[ThomasR]

Howdy all, I read in a few places about how marbling occors in colored plastic, but I found no answers on how to fix/compensate for it.

If anyone has some pointers/information about it I'd be happy to be a knowlege sponge.

-Thomas 8)

[Monty]

Can you post up a pic of what you're talking about so we can try and help you?

If you're talking about the swirling that occurs in silver-colored styrene, I don't believe any remedy exists except to paint over it.

Edited October 29, 2012 by Monty

[ThomasR]

I read some where that in blue/red/yellow plastics that the grain of the plastic creates a marbling effect. I wasnt sure if it would show through the primer and paint.

-Thomas 8)

[Art Anderson]

If you are talking about those strange looking "lines" with differing "surface" texturing (strong enough to be visible, but so fine as to defy your feeling them with your fingers--that's caused by the flow of molten styrene into the tool during the molding cycle. This shows up whenever model companies shoot metallic colored plastic into the molds--the metallic powder in the plastic flows and "swirls" as it fills the mold cavities (most noticeable on a body shell, with its rather large surface area. You can see the same effect by opening a bottle (or a can) of metallic paint--stir it, see how the metallic pigment powder swirls around, creates light and dark areas in the color.

This is unavoidable, for the most part--it's characteristic of injection molding. Sometimes, this "swirling" effect can show through paints, particularly automotive lacquers used on a plastic model. But using an airbrush, and with practice, it can be virtually eliminated from showing through to the final paint finish, in my experience.

Art