Why won't my paint dry and how can I fix it?

[DeltaVee]

One of five or six models I painted yesterday won't dry. In fact, I airbrushed 4 models with the same batch of mixed paint. One of them hasn't dried after setting for a full night. The others dried within minutes.

I was painting with Floquil enamel thinned with Floquil thinner. My suspicion is that, at one point, my tip clogged, so I ran some mineral spirits through the airbrush, cleared the tip and continued painting. The suspect model may have been the first one I painted, so I wonder if the mineral spirits in the mix have kept the paint tacky.

Could that be it? Is there anything I can do? It's a delicate 3D printed model. Stripping it's likely to result in damage - not to mention that it took extended effort to prime it and get the get the surface smooth.

Can I just paint it again with the Floquil paint and thinner and make it dry out? Thanks.

[DaveVan]

I use a food dehydrator to dry all my paints. But if you have a bad chemical reaction then you may have to strip the model and re-paint. Good luck.

[dizzyfugu]

Could also be a material reaction. You mention that it has been 3D printed - maybe the material contains a lot of softener (PVC style), and this generally does not work well with enamels. They won't adhere/bind wit the surface, unless you apply a coat of acrylic primer as a neutral "borderline layer" in between.

Messy situation; I'd recommend stripping off the enamel paint and try an acrylic paint, or at least a primer coating.

[DeltaVee]

Thanks for the ideas. All the models were 3D. All had a pretty thick solidified coat of Gunze Mr. Resin Primer/Surfacer. I've painted a bunch of 3D models at this point. I've primed most of them and had only minor adherence issues. Does anyone know of any reaction caused by the use of mineral spirits in clearing the tip messing with the paint chemistry?

[eeun]

I think patience is your best and least risky option.
If you can provide a relatively dust-free spot, give the model a couple more days - even a week - to see if the paint cures. If it does, great; if it doesn't, you're no worse off and can try carefully stripping it.

And yes, I have found different thinners, like lacquer thinner vs. mineral spirits or varsol, will greatly vary drying times.

[DeltaVee]

Thanks. Kinda the conclusion I'd reached. I'm going to try another coat and see if that prompts it to dry. Just one more layer of paint to strip if not.

[DeltaVee]

Since I model in narrow, pilfered windows of time, I came home, set up the airbrush and gave it the quick once-over. The result: wrong shade, too much paint, dryer lint. Now for good or bad, it's stripped, drying and waiting on a more leisurely window of opportunity.