Abrasive paper designation

[metman]

From my bygone days of metallography and less technical pursuits, I am used to SiC (Silicon Carbide) wet-or-dry paper 180, 220, 320, 400, 600 grit.

At my current job as a machinist we do a lot of sanding and polishing. Cosmetics of the metal parts (about 25 different metals and alloys -- it's like disneyland for metallurgists) is very important.

We have 220 grit and P220.

Ditto on some other grits. The P designation seems to be a finer grit.

What does the P stand for?

 

[Wrenchbender]

Search "abrasive paper p designation". From what i saw, the P-prefix is from a EU standard, while no prefix is from a US standard. Both numbering systems are pretty close in describing average particle size. They diverge in the finer grits with the P-numbers tending to be more coarse - so it says. (Is that contrary to what you are observing?)

http://www.metallographic.com/Newsletters/SIC-newsletter2.PDF

http://wiki.diyfaq.org.uk/index.php?title=Sandpaper

"Very interesting indeed, but tell me, Mr. Faraday, of what use is this electricity?" "Sir, you will soon be able to tax it."

 

[metman]

Wrenchbender
In the first link (have not looked at the second one yet) the table shows the P grades to be finer which is what I am observing.

In the discusion, it talks about Premium grade which could be confused with Eu9ropean or P-grade.

 

[unclesyd]

Here is comparison sheet from Micro-Mesh that might cover your requirements. There are other grades out there that are called out differently by specific industries, the furniture business did have their own nomenclature. Also there are modifiers that are used on the different grades, like closed coat, open coat, wet,and dry along with a few others. Adding to all this there are different backings, like paper, cloth. foam, and fiber pads.

http://micro-surface.com/index.php?main_page=page&id=16