After you've applied your auto body filler on your vehicle, you'll need to apply a glaze. In this video, you'll learn how to apply a 3M Finishing Glaze. Their new Dynamic Mixing System is a good one, and the product mixes instantly when it exits the tip of the gun.
Purge the glaze, but all the product should fully harden on the paper towel. There's minimal waste involved. The product mixes instantly, which will require minimal purging and you can apply only the amount of glaze you need to the surface what you are working on. Therefore, the mixing capabilities are be excellent and wasted product is minimal.