Question about sandpaper grits

Legacy Forum Archive advanced-techniques-and-sharpening-strategies
1

Earlier today I watched this video from YouTuber M0DiFiEDZ:
http://www.youtube.com/watch?v=mA5qy0iLxcU

It’s a 48-minute-long video so rather than expect you to watch it all through the main thing to note is that after the 1,000 grit diamond stones he uses sandpaper (taped to the stones) beginning with 1,000 grit and then going through 1,500 - 2,000 - 2,500.

After he finishes with sandpaper he strops but even before the stropping negins you can clearly see that the edge has started to get a nice mirror polish on it from the sandpaper.

So after watching that I thought I might give it a go and looked on eBay for sandpaper, found some items but before buying decided to come on here and just check if there was any specific advice or brands of sandpaper recommended. So I did a search for “sandpaper”, read through the results and found this post from Mark76:
http://www.wickededgeusa.com/index.php?option=com_kunena&func=view&catid=28&id=8879&Itemid=63#8897

It seems that sandpaper grits are rated using a different scale (FEPA-P) to the scale used for the Wicked Edge grits (ANSI).

So the 2,500 grit sandpaper that M0DiFiEDZ finishes with should actually have been coarser than the 1,000 grit WE diamond stone, and the three sandpaper grits he used before that (2k, 1.5k, 1k) should have been a lot coarser than the WE 1k stone.

Yet you can clearly see in the video that they do improve the mirroring, they don’t reverse the scratches, so what gives? How can coarser grits actually refine the scratches further?

In my searching I did see another post where someone (Curtis, maybe) says that sandpaper wears quickly and can often be a finer grit than rated but even so, you’d expect at least the first two sandpaper grits in the video to do more damage than good, even if the 2,500 paper had worn to the point where it was no longer coarser than the 1k diamond.

On the one hand I just want to buy some sandpaper and give it a go because it’s cheap and seems to work, based on the video, but on the other hand I don’t like blundering into things I don’t understand first so would appreciate some clarification, if any exists.

2

Grit ratings are hard to compare… especially across different media, just by looking at the numbers.

A few years ago (pre Wicked Edge unfortunately), I made a chart where I compared, as best I could, the type of finish left by different media: (waterstones, diamond stones, sandpaper, were a few). On it, I rated 1000g sandpaper around 7 micron, 2000g around 5m, and 2500g around 3m. Compare that with an EF DMT stone (the only diamonds in the list) at around 9m. The WE stone is around 7micron, and Clay seems to have done a decent job rating them appropriately.

Sandpaper tends to cut finer than diamonds, and (like you said I said before) :slight_smile: breaks downs a bit to produce a finer finish. Someone could probably give a more technical reason, but diamonds tend to be more scratchy, even at finer grits, where sandpaper leaves a smoother finish, especially as it gets finer.

The sandpaper I used I got at a NAPA autobody store.

So, unless what you found is different than what I used, it should produce a finer finish. This may be one of those YMMV, situations, you might see a little difference based on how you use it, or the type you get. But in general, I think you’ll find it’s a finer finish.

There might be some on here who’ve used sandpaper in conjunction with the WE stones that could be a bit more accurate, but the video seems to support what I’ve found in the past.

Hope that helps!

3

Cheers Curtis. That does help, yes.

I guess ultimately sandpaper is so cheap (about £4 GBP delivered on eBay for all four of the grits mentioned in large sheets) I should probably just try it and see. I just figured there was no harm asking here first.

Thanks

4

I have used this method and learned it from the same you tuber “m0difiedz” with the same results he achieved. Here was the progression: diamonds through 1K, course and fine ceramics, then taped 2000 grit paper to the fine ceramics, then 2500 grit. Just as you noticed from the video, the pollish is almost instantly recognizable, but there are still trace scratches. Finished with 1 um and .5 um strops. I achieved the sharpest and most pollished results with this combo yet (my first hair whittling edge).

I kind of figure this is an inexpensive way of substituting for a set of Choseras to bridge the gap from the ceramics to the strops. Although the Choseras sound like they might eliminate the scratches a bit better if you progress with them. Just an extra expense for the waterstones.

I bought the 2000 grit at the local woodworking store and the 2500 grit I ordered online.

Hope that helps,
Sauce

5

The company 3M makes sanding tapes (sandpaper with adhesive backing) that are rated in Microns. That way you have a much better measure of comparison.

I just purchased some 1 and .3 micron and can get almost to a mirror… I’m still new to this so I expect my results to improve! I don’t have the link to the site I bought from, but I think a search for “3M” here should turn up the thread I used for a reference.

-Pie