Structural Filler (406 West System Colloidal Silica)

This is a superb filler for critical spots and structural bonds/fillings – it applies beautifully but tough to sand.
This product is a powder that you mix into epoxy to your desired thickness(after you mixed resin with the hardener). It may seem like an extra step but once you try it a couple of times you will love it – it gives you nice control over the thickness of your filling paste: if it runs a bit – just mix a bit more powder in.