Jan 03, 2011· Re: Grinding wheel for fiberglass? Hi mcgyver. For grinding I only ever use standard disc's, in the courser grits. I find I can buy these disks very cheaply if bought in 50/100 boxes. I have tried every new product in the last 30 years or so and still find the standard disk and rubber pad the most economical and fastest, (same thing to me) to use.