Need some painting help

[Cosmeo]

Hey all I am in need of some advice to fix a screw up of mine. I have a problem with paint, adhesion and masking. I have been finishing up the paint on the shells for my outlaw caster gun and am running into probably beginner mistakes.

3d printed PLA that was sanded and puttied to smoothness.
Primed with mr surfacer 1000 black.
Then Alclad gloss black base. Then used Alclad Klear Kote.
Createx airbrush color for the base, Then used Alclad Klear Kote.
masked, createx airbrush for the detail.
disaster.

The masking was a mix of vinyl and tamiya tape. the vinyl was apparently to strong of tack but I tested it on two earlier pieces to see if it was going to be a problem and they were fine and if it was just screwing up the layer i just painted I get that``. What I don't understand is that the acrylic didn't bond all that well to the clear coat layer, but that is what its there for. Why is the the paint ripping all the way to the gloss layer. What is causing this to not bond properly, this is what alclad recommends for doing what I'm doing and it paints fine but once I mask and remove its obvious that I never really adhered but just made a "shell" considering I still want to use the Createx colors as my topcoats to fit with my prop, what should I be using. help!

back decals got mangled one ripped paint to the gloss.

Hard to see but the vinyl ripped the whole bottom purple off.

This is ripped all the way to the gloss

 

[renaissance_man]

How long did you allow between paint coats and also after painting to clear coat.
I find it best to wait the absolute minimum of 24 to 48 hours for any paint to cure before putting any masking tape on any painted surface.

Also did you wash and dry the PLA print before priming? Sometimes uncured resin leaves a film on the surface which is a complete barrier to any paint.

 

[Cosmeo]

How long did you allow between paint coats and also after painting to clear coat.
I find it best to wait the absolute minimum of 24 to 48 hours for any paint to cure before putting any masking tape on any painted surface.

Also did you wash and dry the PLA print before priming? Sometimes uncured resin leaves a film on the surface which is a complete barrier to any paint.

Day in between for each, my work schedule works like that, so gloss was sunday, clear coat was monday night, base was tuesday, wensday was clear coat, last night was masking and detailing with the masks coming off two to three hours after painting.

Yes the parts got washed after all the surface work, and it seems the primer and the gloss layer are good not pulling anything up past that it seems at least.

 

[Duncanator]

If I am reading your description correctly, the Createx paint is going on over the gloss clear coat.
That may be your problem.

Most paints want a slightly "rough" surface to stick to - even if it is just micro-scratches from a sanding sponge.
The scratches give the surface some "tooth" for the paint to grab a hold of.
Paint sprayed on to a smooth glossy surface has nothing to grab on to, and can peel off easily.

If there is any way you can roughen up the glossy surface before spraying on the Createx paint, I'll bet it'll help with your adhesion issue.
It doesn't need to be much - 3M pads, fine grit sandpaper, fine steel wool, etc...

I hope that helps!

 

[Cosmeo]

Thanks for the suggestion, I have some 3000 and 5000 sanding pads I use when wet sanding gloss and I didn't consider the steel wool. I'm going to do some testing a bit later.
I ended up stripping it back to the primer, then used only acrylics to do the base gloss and detail layers. its not quite as smooth or shiny as the lacquer with the metal paints but it takes masking. then used a gloss acrylic varnish did some oil washes and then put on the matt varnish to bring the shine down.

 

[joberg]

I feel for you man; all that work and boom!...You've mentioned using Tamiya tape (that's the only one I used for masking; especially with that many coats. As others have mentioned also: rough surfaces are better. Steel wool quadruple zero is one of the trick and I would leave those paint layers dry for 48 hours if I were you.
Good luck