I have a problem with Tamiya acrylic paint. It dried too quickly, so as I keep on brushing, it created some kind of broken thin coats. It also, in some area, aren't colored enough, so I have to repaint repeat. Unfortunately, it already created a thick coat. A few years ago, I was given a tip to resolve that problem. It did so and was surprised it was very good. Unfortunately, I forgot that tip. Anybody help me?