I used the Do-It powdered product as an addition to the raw plastic when I am making my batch. If I want to add uv to a plastic I am re-melting, I use an different product that is liquid.
The powdered product is very strong. Here's is how much I put into a colored plastic like chartreuse or fl.orange, blues, purples ambers....basically any color that is transparent except my bluegill glitter, pearls, whites and clear coat for eye which get about 1/2 of this amount shown in the picture. I'll double this for opaque colors and black.
That is a typical popsicle stick that I use to stir my plastics.
