: It will end up looking milky. Unless you're going to paint the
: boat, don't do it. It's also a real bear to sand!
+1
All the 'No Sag' (fumed silica) I get nowadays seems to mix up to be translucent at best. It also doesn't seem to mix well in low concentrations.
I recall that when I used 'real' Cabosil, it mixed up easily into a transparent, (vaseline-like) paste.
So there may be brand differences in clarity. Or does it have a 'shelf life'?
Sanding silica is about as much fun as sanding rocks (no surprise there...).
I second the suggestion about using WEST ultralight fairing additive if you are painting the boat- it's pricey, but you will save the cost in sandpaper.