Previously sanded off details come back after clear coat...

[Jamese30]

Hi All

On my Sunbeam kit i sanded off some Tiger decals to turn my Tiger into an Alpine. I sanded primed, sanded and primed again until the detail had all gone. They were not visible after the vase coat of Tamiya paint but then after the automotive clearcoat was applied and dried they reappeared as a silhouette.... visible in some light.

I'm guessing my lacquer is a bit "hot" and has pulled the paint down.

 

Any ideas????

 

James

Edited 19 hours ago by Jamese30

[peteski]

Yes, "ghosting" can be a problem.  As I understand coating the sanded areas with liquid cement (basically melting the plastic surface back into solid state) BEFORE priming and painting will prevent this from. But that isn't much help to now.

[Bainford]

This phenomenon is called 'ghosting'. It is quite common when using 'hot' paints over sanded-off body features. 

Though I haven't tried it, I have heard that painting on a layer of thin liquid model cement over the sanded surface before final sanding and primer can prevent this from happening.

[sidcharles]

agent #99 . . .

[LOBBS]

Ambroid Proweld or a similar hot solvent glue brushed over any details like that will make them "pop" again and you can resand them smooth for good. Kinda like taking a damp rag to woodwork to make the grain stand up before laying down your stain and varnish.

[SpeedAndViolence]

Not even a primer/sealer will work? I thought that was the whole point of using a sealer? 

[LOBBS]

9 minutes ago, SpeedAndViolence said:

Not even a primer/sealer will work? I thought that was the whole point of using a sealer? 

"Ghosting" occurs due to stresses in the plastic from the injection molding process. The hot solvents, whether from using a glue before painting or from a hot paint, relieve some of that stress causing the sanded off details to rear their ugly heads again. 

[Straightliner59]

Zinsser BIN will definitely help. Apply it under the primer.

[Chris V]

"Ghosting" is a common phenomenon caused by differences in the density of the plastic from the injection molding process:

As the molten plastic cools from the outside, microscopic pores form towards the centre of the part. By trimming/sanding off bodywork details, you expose a surface that's closer to the core and thus more porous/vulnerable to solvents in the paint than the immediate surrounding area.

By giving the area a gentle wash of liquid cement you essentially saturate the porous plastic with solvent and binders, causing it to "collapse" in advance, allowing you to fill in any cavities left as the cement evaporates and sets. Always allow the plastic ample time to thoroughly dry and set before proceeding with the surface preparation and paint.

The severity of the ghosting varies a great deal depending on the type of plastic and the paint you use. Some automotive type lacquers contain highly volatile solvents, and in some cases ghosting can even happen on surfaces which have been thoroughly prepped:

 

Edited 3 hours ago by Chris V

[bobss396]

I've had ghosting happen MONTHS after paint/clear was applied. Too many solvents too soon.