Existing paint shows through. Model-making acrylic paints, as a matter of fact, allow a lot of "bleed-through" if you only apply 2-3 coats of paint. Now, you COULD, theoretically, COVER a prepainted part with acrylic paint and cover up the existing paint ENTIRELY, but you'd end up with an overpainted mess of a part. I wouldn't do it.
That would make sense. The only experience that I have with repainting is changing a G1 Magnus into a G1 Optimus. I didn't remove any paint. Of course, that is probably a simple repaint compared to what some are doing.
Your best bet for getting a good clean paint job, in terms of repainting any toy, is to remove the paint from the area you're going to repaint. I've tried repainting figures & toys without removing the source paint before and, inevitably, the source paint shows through eventually, whether it's as a result of the top coat aging or handling the toy.
You sometimes get a bad reaction between paints as well. Like when I use the vinyl dye/paint, it does not want anything underneath it besides bare plastic. You end up with paint not sticking and thus never drying. Gets annoying when handling your toy.
QFT. That bubbling response you get when you try to run an acrylic brush over enamels is...rrrrgh. Lesson learned.
Huh...well quite contrary to the other responses, I generally find painting over a prepainted part produces better results than bare plastic. I normally give just about anything I paint a light sanding from very fine sandpaper (800 or so), maybe that makes the difference? Jarrod
