These bulking agents are hollow, clear microscopic spheres that make a low cost, low density filler. Added to epoxy resin and hardener mix, they make a good, heat-resistant, light-weight fairing compound with good compressive strength. Mixture can be blended with a small amount of Silica Thickener to prevent sagging.
Not recommended for glue.
Alternatively use SilverTip QuikFair for ease-of-use.