: I am refinishing the top of my kayak, I had to sand the top completly down to
: bare wood.

That sounds like a mission. It is my understanding that rather than grind up heaps of toxic glass dust (by sanding all the way down) that good results are achieved by using a heat gun to soften up the glass which then can be removed with a paint scraper.

You probably still want to use a respirator.

Good luck

Pete