In case you haven't yet been enlightened to the existence of this wonderful industrial supplier, let me point you in the proper direction:
McMaster-Carr Supply
The website is rather awkward to navigate, and the choices are overwhelming, but neither of these facts detracts from the usefulness of this supplier. Tools, raw materials, abrasives, metals, composites, honeycomb products, pipe fitting...and so on and so forth.
With warehouses located strategically around the country, you can count on amazing service. Orders placed on one day are frequently at your doorstep the next--with regular ground shipping. Absolutely amazing.
I have found the abrasives to be second to none, and stock up frequently on the hard-to-find 5" sticky back discs that I use. Whatever you think of the prices for these abrasives--yes, there are cheaper alternatives--rest assured that there is no better sanding value. Cheap sandpaper has a very short life, while this industrial-strength stuff will outlast anything I've ever tried.
Anyway, check this supplier out for yourself. You'll find a multitude of uses. Forget about getting a print catalog--they won't send you one. (It's one of those 5000 page catalogs.) Suffer through the website, be persistent, and find what you need. It's all there, and worth it.
Tim