Official Luthiers Forum!

This topic seems to come up here from time to time in discussions. It just came up again the other day and rather than hijack I thought I'd start this thread. Invariably when the topic of sandpaper grits comes up at some point the difference between rating of grit size comes up. There are P, CAMI (ANSI), JIS & micromesh grits. Since I have never been to Japan or the far east I am not surprised I never seen a piece of sandpaper JIS graded. I have seen and used micro mesh but not in woodworking (I use it to polish frets). But in all my years as a professional woodworker and finisher I have never bought or even seen a piece of CAMI graded paper. It's all been P graded. And believe me when I tell you I have bought a lot of sandpaper over the past 35+ years. Kind of odd being P is the european standard while CAMI the American and I live here in the USA.

So to those who have had some, where did you get it? Who typically uses it?

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I need to order some sheets for general sanding, 100 to 400 grit.
Suggestions would be appreciated.

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wah
Wah-wah-wah-wah
Wah

Most hardware stores and auto parts in southwest PA used to carry ANSI paper. But over the last 8 or 10 years it has become more scarce. I have a few sheets of 400 and 600 ANSI left.

Chuck

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Dan we like Sait papers a lot! Prior to this I liked 3M Gold but the Sait stuff has better backing that holds up longer and it does not seem to clog easily either.

I am sure you had CAMI paper in the past but you probably didn't know it because it is not labeled as such.

Brian,
A quick search of my shop shows everything 400 and below is Pgraded as well as some StewMac paper I got up to P800. All the other higher grades (incidentally wet/dry) 600 to 1200 are the CAMI (ANSI). As noted above, this can be identified only by lack of the P in front of the grade,
Mike

I have some wet dry paper that I got from an auto body supply place that doesn't have the P in front of the grade.

I asked them what the grading was and they said it was all P grade. This might explain why I could never remove the P320 grit marks with the Wet Dry 400 grit. Also if I've actually been sanding with 400 which translates to P800, then I'm way farther along that I thought I was once I get things level.

Of course that's assuming I'm correct in my interpretation of the chart I just looked at on the internet.

I just did a check and it looks like I'm all over the place.

The stuff I got from the Auto Body paint store all has a P in front of the number.

The other stuff I have is 3M or not branded and I either got it from Home Depot or Lowes or Autozone. I cant remember where. My 400, 600 and 2000 grits are without the P. I have P800, P1000, and P1500.

Be aware when going from the grit specification when mixing types of sandpapers. I have chart I found long ago that compares the various types of papers, p graded, cami and a few others to the actual micron size of the grits. In Johns grits listed above the p800 is actually between the 400 and 600. You actually learn this pretty quickly when sanding out finishes, so hopefully this isn't a surprise to anyone, but...
P-grade and CAMI track pretty close up about 220 and start deviating beyond that.
I wish all abrasive just had micron size on them, it would be so much clearer.

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Jim Watts
http://jameswattsguitars.com

The "papers" with micron size listed on them have more uniformly sized particles. They cost more and work better when sanding finishes. And then there are trizact sheets which don't look like sandpaper at all but also work well for polishing finishes.

Thanks to advice right here on this forum, I have completely switched to dry sanding using 3M gold no load paper. I have a cloth door mat that I set the guitar on, and when the paper get loaded with dust, just tap in on the carpet, and its good as new. I have a pak of Norton's no load from before, and am willing to give it a try to see how it compares to the 3m, but for now I'm sold. (also got a stick of pre-polish menzerna and some new buffs to try on the next one)

That is not necessarily true. I have some 3M wet/dry papers that are not labeled as P on the the paper but are P graded as labeled on the sleeve. They are old stock, all the newer stuff has the P on the paper.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I get all my sandpaper as 3M product from auto-supply or industrial paint suppliers. 50-sheet professional packs are much cheaper than anywhere else. But I've noticed recently small 3M packs on display at H*me D*pot that are graded on the packaging as 120, 220, etc., but the papers themselves are P-grade. It's not the gold stuff. Talk about confusing the consumer!


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Interesting; I think in the future I will only purchase clearly labeled P grade sandpaper and eliminate the confusion,
Mike

^^^ Agreed - I went through my stash and found a few of my W&D sheets were labelled with an "A" or no letter at all... P all the way - at least until I haul out the Micromesh pads....

and Micromesh uses yet another grading system

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Jim Watts
http://jameswattsguitars.com

Yes, but at least I know when I pick up a piece of my micro mesh!
Mike