Phenolic Microballoons Filler for epoxy and Polyester resins 1/2 Gallon

I've used this before, and when I found this quantity for the price I couldn't pass it up. It will last me a very long time. I use it for filling balsa and plywood parts on my model airplanes. When mixed with epoxy, it's lightweight, dries hard, and is easy to sand.

it is exactly what the package says, they work like they are supposed to. After sanding it take a little fairing with unthickened epoxy to fill the voids for a primer/paint ready surface.