Sandpeper grid

A question to the Americans here.

I just bought the micromesh kit for remove some scratches from my ports, read the instruction and sow that before using the micro-mesh need to sand the surface with 400 grid sandpaper - no problem, I have it in my toolbox but its looked too coarse to me so I checked with my wife that sand her polymer-clay works and she show me some sandpaper from the states she have, It's 400 grid but much fine then my 400 grid.

So my question, what product you use for that purpose and where you get it, if I ask for a 400 grid sandpaper in American ACE it will be the correct product I need?

Do this 400 grid is standard every where there?

There are two standards for sandpaper (AFAIK), the ISO and the CAMI.

ISO 400 (sometimes P400) has an average particle size of 35 microns or so, while the CAMI 400 has a particle size of 23 microns which in ISO world is P800 more or less. P800 is somewhere between the CAMI (U.S.) sizes of 400 and 500. I think the differences are due to mesh sizes in mm or inches so the factor of 2 or so makes sense.

Bill

Bill, Many thanks for the info.

You should not use "sandpaper" on plastics. This is generally used on woods. I believe the best type would be Silicon Carbide. You can find some good info at http://www.mcmaster.com/ See page 2532. Hopefully this will help.