Am in the middle of building an Invader and using Humbrol 155 matt for the bomb color. I brush painted it about 24 hours ago and it is still tacky. It is one of the tins made in England, one of the newer batch. I am also using other Humbrol paints and they seem to be drying normally. Usually for a matt paint, it is not tacky after about 1 or 2 hours. After 24 hours, the paint is still tacky. Any suggestions. Since the other Humbrol paints are behaving normally on the kit, do not think it is something on the plastic or a reaction with the plastic. Did not use a primer, but didn't use a primer for the other parts. Any suggestions would be helpful, otherwise, thinking about stripping it all off and redoing the bombs with another brand.