First, the hand poured plastic has to be fairly cool before the colorant is dabbed on it. Second, you have to be careful how much colorant you put on the hand poured portion. I've had very limited success using any colorant other than the X2 products because others are just to thin to show up well. Too much colorant will prevent a decent weld and can leak into the mold creating one heck of a mess. The process takes some serious practice and even then there is no way to predict how things will turn out.