Sandpaper grit equivalents

[Greensleeves]

Where can I find information on comparing older sandpaper grit numbers, like 150, 180, 220 etc. to newer numbering like P100?

[thekl0wn]

How "out of the times" am I? I've never even heard of a new numbering system. :confused:

[Don]

Hey, Greensleeves and welcome to the forum.

I found this on this site; http://www.onlineindustrialsupply.com/frasqu.html

Grit size refers to the size of the particles of abrading materials embedded in the sandpaper. A number of different standards have been established for grit size. These standards establish not only the average grit size, but also the allowable variation from the average. The two most common are the United States CAMI (Coated Abrasive Manufacturers Institute, now part of the Unified Abrasives Manufacturers' Association) and the European FEPA (Federation of European Producers of Abrasives) "P" grade. The FEPA system is the same as the ISO 6344 standard. Other systems used in sandpaper include the Japan Industrial Standards Committee (JIS), the micron grade (generally used for very fine grits).

And here is a link to the their table; (scroll down to see it)

http://www.onlineindustrialsupply.com/frasqu.html

Yes, Lee - we're both out of the times a little, but in this case, it really doesn't matter too much. The grit equivalents are very similar up till around a 1000 or so then they begin to deviate. Remember the days when you could just put your hand on some paper and say, "finer or rougher?"

All the best, Don

[jcclark]

It seems that most mfg's are going to the "P' series grit numbers.
It's played havoc with me on my car painting jobs.
I don't know when it happened but all my 3M paper now has the
"P" numbers and most people, including the store where I buy it,
doesn't even realize it's different.
I posted a chart up in my shop and refer to it often.
I have sandpaper of both designations, it's confusing.:cool:

[Terry Mac]

The only run-in I've had with the P series, it was labeled as "course, medium and fine", kinda like emory cloth. Not sure how that adjusts or compares to sandpaper grit.