Great for working with all metals, including platinum, sponge sanding pads from 3M are flexible enough to conform to almost any contour or surface. Micron-graded abrasives make them safe for every stage of sanding and pre-polishing. Use pads wet or dry for a wide variety of metal, model-making and lapidary applications. These high-quality pads are made of long-lasting, closed-cell foam rubber and permanently bonded with aluminum oxide abrasives. They won’t gouge surfaces and the convenient, hand-sized pad can be folded or trimmed to fit into detailed areas. Super-fine grade.
There are many ways to measure the individual particles that are embedded in abrasives. And because manufacturers differ slightly in their measuring systems, and particle shapes vary so much, it's nearly impossible to offer a standard comparison between grit sizes and micron sizes. There are, however, some good estimations that will help you determine which abrasive to use. NOTE: This table is an approximation and is for comparison only; measurements will vary from one manufacturer to another.