Sandpaper sharp

[AStone]

After a lot of reading for weeks about sharpening with sandpaper/emery cloth,
and being temporarily too poor to invest in good ceramic (but soon),
today I went to both local hardware stores seeking sand.

My research has suggested that I start with 400, then go to 1200.
So, I sought those grits. (I grew up in the south, so "grits" has multiple meanings.)

At the locally owned - which I want to support -
I the finest was 400. I picked up a couple of sheets. Right: sheets.

Then I went to the big box hardware up the hill by the Interstate.
There, the finest was 600, and it was only available in a package.
I bought a package. It has a purple color.

I brought them home, ate dinner, cut one sheet of each into fourths,
and started sharpening my Spyderco Manix 2. It's my EDC
(but soon to be replaced as EDC; will become a backup),
and has always had a good edge, but not great.
(Blame it on my stone technique; I'm learning.)

But after < 10 min work with the sand,
this Manix has the - THE - sharpest blade
since it came out of the box two years ago.

I'm NOT suggesting that
sand paper is the best way to sharpen.

I'm acknowledging that I finally understand grits,
and why starting rougher than the stone
and working finer is important.

 

[hso]

It is very important to put the paper on a stable surface that is flat and smooth.

 

[AStone]

^ Totally agree. Thanks for pointing that out.

I put mine on my desk top, right on the edge -
bent the paper over the edge -
just for starters, to try it out.

I'm reading about other ways to make
a block with wood or - better - glass.

I am very open to tutoring.

 

[jbkebert]

Auto parts stores that sell automotive paints typically have a great selection of fine grit sandpapers. Also quality paint stores will have a better selection than a box store.

I picked up a couple sheets of 4000 grit to gently buff a onyx panel. Its about as rough as a kleenex. About $2.50 a sheet at Napa auto parts about 6.25 a sheet at a paint store.

 

[AStone]

^ Excellent suggestion, JB.

Don't know why I didn't think of that.

 

[hso]

A table or desk isn't a good choice.

Try to find a piece of float glass or a flat die block. A chunk of granite counter top or composite like synthetic granite is a good choice.

The table/desk/etc. just isn't flat and level enough.

Alternately, you could work the edge into a convex using leather or high density rubber balsa wood and strop instead of using the paper like a stone.

A pawn/junk shop palm sander that you can strip the mounting backing off makes for a good plate.

 

[AStone]

Repeating from post 3, with emphasis.

I put mine on my desk top, right on the edge -
bent the paper over the edge -
just for starters, to try it out.

I'm reading about other ways to make
a block with wood or - better - glass.

Yes, we're on the same page.

 

[kBob]

Yep, auto parts places in the paint section and if you were raised in the south you gotta go to NAPA.

If there is a hobby shop locally that sells Cub Scout "Pinewood Derby" supplies they some times have packets with small sheets of paper about 4"x4" of various grits from "pretty rough" to "are you sure this is sand paper" also such packets of mini sheets show up wherever plastic models are sold as well. More expensive for what you get than big sheets at the auto store, but a good sample to play with.

Keep in mind that perfect is the enemy of good enough..... and good enough is good enough. Get'er done.

-kBob

 

[sniperlongshot]

the beveled edge of your car window can do a nice job also

 

[AStone]

Keep in mind that perfect is the enemy of good enough.

I like that.

There's no NAPA in this city, but there's an AutoZone
on the other side of town where I'll be on Monday.

Sniper, I don't own a car right now,
but I'll check my bicycle window.

It's an interesting suggestion, though. I'll file that one.

 

[Jason_G]

FWIW, if you're going to go the sandpaper route, I found that it helps prevent scratches and imperfections in the edge if you at most double the grit count as you move up (at least IME). For example, maybe start with something around 400, then something close to 800, then 1600 (I've never seen a 1600 grit, so you'd likely go to 1500 here). You can go more gradually than that, but double is the max I will jump as I transition up. That's not to say that you can't go from 400 to 1500 or so, but this gradual approach to sanding makes less scratches for me, and is also a little faster (maybe not that noticeable on the tiny area of a small knife edge, but definitely on edges of bigger blades or larger flat areas that need polishing/refinishing). That's counter-intuitive to most people. Folks tend to think that they're doing more work faster if they jump to a much higher grit, but if they want the scratches out, they're making much more work for themselves. Once you start approaching 2000, you're basically working with a mirror edge (which may or may not be sharp, depending on your technique). I sand both sides equally, working up to the finest grit I want to use, and then with the final grit, I make a burr all along the edge of one side, then remove it by sanding the other side. It usually doesn't take much to get the burr off, so I try to use a light touch. After that, I strop on leather or cardboard.

Sandpaper is a totally legit way of sharpening, although I use stones much more often. Sandpaper will produce a very sharp edge if done properly.


Jason

 

[AStone]

Sounds reasonable to me, Jason. I can understand the logic there.

I read something interesting last night on a sharpening page - bookmarked somewhere - in which a guy sharpened his short blade differentially, with finer grit at the tip for a more polished edge, but with a courser grit on the rear half of the blade, to leave the edge a bit more coarse. His argument - based ostensibly in his experience - is that he uses the rear (straighter edge, less belly) to slice through things, and found that easier if it wasn't as polished.

I think I'm representing his argument correctly, but could check if this is of interest.

 

[LeonCarr]

It is amazing the grits of sandpaper you can find if you look around. A buddy of mine who was a Weapons Troop (Loads Ordnance/Guns on Aircraft) in the Air Force had a bunch of what looked like brown wrapping paper lying all over his barn/shop. I asked what all of this paper was and he said its not paper, its 8000 grit sandpaper used for cleaning the cockpit glass on F-16s. Great for final polishing.

Just my .02,
LeonCarr

 

[zhyla]

I do something like 220, 320, 400, 600, 800, 1200, 2000, and then some honing paper. The lower grits are skipped depending on blade condition.

This is how I sharpen things where sharpness actually matters (straight razor, plane irons). If done correctly you'll end up with a mirror finish and a killer edge. Careful with your angles though, you want to mimic the original bevel unless you really know what you're doing.

 

[Jason_G]

I read something interesting last night on a sharpening page - bookmarked somewhere - in which a guy sharpened his short blade differentially, with finer grit at the tip for a more polished edge, but with a courser grit on the rear half of the blade, to leave the edge a bit more coarse. His argument - based ostensibly in his experience - is that he uses the rear (straighter edge, less belly) to slice through things, and found that easier if it wasn't as polished.

Yeah, that's not too too uncommon. The scratches from the coarser sandpaper will act like little micro-serrations if done well. I've never had any luck with that approach. It seems like it just quickly turns into a mediocre edge for me when it gets used. Of course, I've honestly never given it too much of a chance, either, since I prefer a polished edge anyway. YMMV. It's definitely worth trying out if you think it might be of benefit to you. I can see the appeal if having to cut through certain tough materials like plastic, where some tooth on the edge would be of use. I haven't found a way to make that "toothiness" last very long though. Could just be me though.

It is amazing the grits of sandpaper you can find if you look around. A buddy of mine who was a Weapons Troop (Loads Ordnance/Guns on Aircraft) in the Air Force had a bunch of what looked like brown wrapping paper lying all over his barn/shop. I asked what all of this paper was for and he said its not paper, its 8000 grit sandpaper used for cleaning the cockpit glass on F-16s. Great for final polishing.

Yes. They also make lapping films for different uses, including fiber optic line repair, that get up to some ridiculously high grits (over 10,000), although they tend to start measuring the grit size itself in micrometers, rather than the standard grit count like you see on sandpaper. At least I believe that's the convention. There are also Japanese water stones that go up above 10,000 as well (pricey).


Jason

 

[ugaarguy]

Yes. They also make lapping films for different uses, including fiber optic line repair, that get up to some ridiculously high grits (over 10,000), although they tend to start measuring the grit size itself in micrometers, rather than the standard grit count like you see on sandpaper. At least I believe that's the convention. There are also Japanese water stones that go up above 10,000 as well (pricey).

I actually started researching this when I was looking at additional stones and micro diamond paste strops for a Wicked Edge sharpener. Grit sizes vary from standard to standard, and there are several standards. A quick comparison is that the 6.5-7 micron size equates to a JIS (Japanese) 2000 grit, FEPA-F (one of several European standards0 800 grit, and ANSI (one of several American standards) 1000 grit.

Here are several links:
http://www.reade.com/resources/part...-chart-astm-ansi-jis-bsi-afnor-din-tyler-uss-
http://www.washingtonmills.no/products/grit-sizes.html
http://www.uama.org/Abrasives101/101Standards.html
http://www.fine-tools.com/G10019.htm

Enjoy deciphering all that.

 

[Jason_G]

I wonder if the conversions between standards are linear?


Jason

 

[hso]

Take a look at the posts from The Tourist here on sharpening.

A dedicated sharpener, he used a range of materials and grit to sharpen based on the application.

 

[Bartholomew Roberts]

His argument - based ostensibly in his experience - is that he uses the rear (straighter edge, less belly) to slice through things, and found that easier if it wasn't as polished.

The only place I've had much luck with that myself is cutting line. By and large, it seems like a polished edge works better, though it will occasionally want to slide off some surfaces instead of bite.

 

[blindhari]

Hello nematocyst,
When I started carving I needed to be able to sharpen and touch up tools and knives. I did not have a lot of money but my brother in law had a cabinet shop. What we did was utilise sink cut outs that are normaly thrown away. We found some flat ones in fake marble, checked them with a machinists level, then cut into size for a 1/2 sheet of sand paper. A little spray on glue with a heavy weight made a decent sanding block. Then we drilled each one to take a 1/2" bolt and used a wing nut to hold it to my bench. In this manner I could change paper by just bolting down a different sanding block. Total cost, less than twenty bucks and I can put a mirror edge on anything from an axehead to Twin Cherries carvers.

blindhari

If you really want serious sharp go to a lapidary, rock, shop and do this with cerium oxide and a tight stretched piece of leather. As iremmeber cerium oxide is around 25000 grit

 

[conw]

How's the edge holding up on the sandpaper sharpened manix? I ask because I've seen knives get pretty sharp with an edge that wouldn't last if it wasn't held at a consistent angle. Imagine an overly obtuse rounded bevel with just barely enough meeting at the very edge to last a bit. It looks and feels sharp but doesn't last long.

You see this a lot with novice sharpeners (I am one sometimes ).

As for sandpaper, it works well. The semi convex strategy hso mentioned is the most expedient. You'll find the sandpaper sharpens aggressively but doesn't have a long life compared to any other sharpening media.

 

[AStone]

Guys, thanks much for continuing to add advice and suggestions.

I'm a little behind reading here, let alone putting this into action, because my new ESEE 3 arrived yesterday (go here, scroll to post 21; I'll be spending extra time in that thread for the next week or so), so I'm kinda pre-occupied.

Fortunately, it came out of the bag very sharp, so I won't need to touch it up for a few days, until after I get to know its edge.

 

[Deltaboy1984]

Shoot I have used a 4 way emery board I grabbed on day at a Sally's Beauty Supply Store.

 

[Zeke/PA]

Believe it or not, in the past I've touched up a filet knife using one of the wife's emory boards while surf fishing.
Since then I make sure that I have a ceramic stick in my surf fishing gear.

 

[AStone]

Zeke, which ceramic rod, please? I want one of those in my basic portable sharpening kit along with sandpaper. (I'll probably start a different thread on V-sticks, but would enjoy knowing which portable stick you use.)