Re: Grinding wheel for fiberglass?
I concur with YD, the fiber reinforced sanding discs are the cats meow when it comes to ripping through fiberglass without ripping thru multiple flappers.
The problem with flappers is they wear out relatively fast as far as the initial sanding aspect goes ( meaning you can feel the loss of traction/cut ) You have to wear away cardboard to get to the next strip of grit underneath, which means they cut great when new, but they are much slower when you've started to have to wear thru the cardboard to get at some fresh grit, which means you also have less surface area of grit that you are actually using. They DO work, but you need to understand HOW they work to get the most out of them and your session. One advantage though is you don't have a sharp edge that you could burn through the glass with once they've been used...nice rounded edge which is great for feathering if you are new to grinding glass.
The fiber reinforced discs are on a semi rigid backer which are going to be less forgiving, but better than a stone wheel.
The stone wheel has the advantage of not being able to accidentally tear if you get into something you shouldn't, like a staple. I briefly used the wheel, but thought it to be more tedious than either the flapper or the disc.
