Okayyyyy, trying not to sound like an expert here, which I'm not, but being a life long brush painter I ran a few experiments with painting
Tamiya acrylics a few years back, because I'd heard what a PITA it can be to brush-paint.
First off, I suspect there was a compatibility issue, in only that enamel clears are hotter than water based clears, but I suspect the main issue was with the
Tamiya paints.
Tamiya paints are notoriously bad for brush painting because, asides from the crap coverage and quick drying time, they have a tendency to lift when you apply a second coat (or even go over a dried section whilst still applying a first) due to reactivation. They are also rather fragile and don't tend to adhere to the base plastic very well - a primer it pretty much a must-have.
There are things you can do to make it better, in fact I got it to the point where I could bash it around quite a lot, but it gets to the point where the hassle is not worth the effort. Certainly trying thinning it with
Tamiya's thinner and adding some
Tamiya flow enhancer - that will improve things.
But prime, prime and prime again.
I do suspect the enamel paint/clear reactivated the
Tamiya paint and just lifted it off the surface. As I said above, if you stripped and re-primed the part, and then painted and clear coated it, you might have better luck.
