# sandpaper sharpening



## Spidey82 (Oct 29, 2002)

Hi, *is sharpening knife with sandpaper bad? i never heard of people doing that.*
i tried to sharpen my knife with fine(600)sandpaper, it seems to work fine. i use table a as a base for the sandpaper. 
I am no where good at sharpening, but the result is better than using sharpening stone, but it can be due to 2 reason,

- the sharpening stone is not as fine as the sandpaper.

- I sucked at it.

Just in case you are lost, my main question is in bold above.
Thanx
Linfeng


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## [email protected] (Oct 29, 2002)

In my *very* limited experience, you can sharpen it with the 600 sandpaper, but to really hone it so you can shave with it, takes something finer...

I'm sure there are much more knowledgeable people who can answer this, but I hope this helps a little bit.

Here is a site with a lot of info about sharpening: Steve's Knife Sharpening Site


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## Steelwolf (Oct 29, 2002)

Sharpening with sandpaper is quite similar to sharpening with a stone. The grit number of the sandpaper corresponds to the grit number of the stones. For a shaving edge, I would usually go for at least 1200 grit up to 4000 grit (depends on what's on special




).

In fact, most knife makers would use their belt grinders to do the sharpening by using a sandpaper belt. 

The most common reason why you suck when you used a stone but was able to do it with sandpaper is that the quality of the stone is no good. Stones commonly available from stores like WalMart, Target, KMart, etc. are usually hopeless, especially those double-sided china-brand ones. The grits are not suitable and the matrix is too hard, which means the particles don't cut properly and as they are worn down, they don't break away to reveal new cutting particles.

If you are using a good stone, like Arkansas Stones, a possible reason is that the stone is loaded. This means that the surface of the stone is filled with the grindings, dust and tailings, which then prevent the knife edge from actually engaging the cutting particles. You need to scrub the stone with a Brillo Pad or Scotchbrite pad to clear the surface. In extreme cases, you may even need to cut off the current surface. Bench grinders have a diamond stone for this purpose, but I don't know what will work for a bench stone. Usually, scrubbing with Brillo pads will be enough.

Sandpaper makes for quite a good and cheap solution in place of regular stones, especially since you can just throw out the paper when it doesn't work anymore. Some of the better stones cost quite a bit of money and you would not be so willing to throw them out.

Some tricks with sandpaper. You can construct construct something like a bench stone if you have a piece of smooth hardwood timber lying around. Cut it to a convenient size and use spray-on mounting adhesive to quickly and easily stick on your sandpaper. Put rubber feet on the other side to prevent the block from slipping. Spray Mount adhesive, like that available from 3M should be available from any store that sells stationary or artwork supplies.

You can create a convex edge (which is good for blades meant for chopping) by sticking on a 3-5mm thick piece of rubber on the wood block before mounting the sandpaper. The rubber will give a little as you sharpen, allowing a convex edge to form.


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## [email protected] (Oct 29, 2002)

> Originally posted by Steelwolf:
> *
> You can create a convex edge (which is good for blades meant for chopping) by sticking on a 3-5mm thick piece of rubber on the wood block before mounting the sandpaper. The rubber will give a little as you sharpen, allowing a convex edge to form.*


<font size="2" face="Verdana, Arial">Thanks Steelwolf,
that's a great tip!


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## JackBlades (Oct 29, 2002)

If the knife steel is of decent quality, you will wear down the paper (thus turning it into a finer grit) in no time. Get yourself a DMT diamond stone (I have red=semi coarse & green=fine) then practice with it on your cheap kitchen knives till you can hold about a 19 degree included angle over the length of the edge. Spyderco makes a nice sharpener using 2 ceramic sticks mounted in a block in a Vee configuration. As long as you can hold the knife vertically, they will produce the proper angle. Good for beginners.


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## Spidey82 (Oct 29, 2002)

thanx ppl. i thought 600 grit is fine enough, 4000 grit? is it smooth to touch?


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## Minjin (Oct 29, 2002)

I'd highly recommend going to a glass shop and asking for a piece of scrap thick glass in the size you want for a sandpaper base rather than using hardwood. I have a long piece glass that I put sticky sandpaper on to resurface brake pads. You want a perfectly flat surface...

Mark


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## txwest (Oct 29, 2002)

Razor Edge System, which is a knife sharpening system, sells what they call a handy hone, for field use. It's a block of wood & some emery cloth with stickey on one side. Must work OK, & I'ld prefer to take that in the field to a expensive stone. TX


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## Owen (Oct 30, 2002)

*You can create a convex edge (which is good for blades meant for chopping) by sticking on a 3-5mm thick piece of rubber on the wood block before mounting the sandpaper. The rubber will give a little as you sharpen, allowing a convex edge to form.*
Good stuff. Another simple way is to use a mouse pad under the sandpaper-picked that one up from Buzzbait on Bladeforums. Wal-Mart has plain ones for $1.47 (and plenty of sandpaper grits that are appropiately sized in the automotive department). Works great, especially for knives with full convex grinds.


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## Steelwolf (Oct 30, 2002)

For field sharpening, I still prefer a good medium grit Arkansas stone. Not too expensive at AU$10 for a small pocketable stone.

Glass as the backing is very good as it is harder than any steel used in knives. It provides a good hard surface that doesn't give and so will allow a flat edge to be sharpened (assuming you can hold the angle). Hardwood works quite well too, and is a little less delicate than glass. Very important for my butter fingers. Any way, when using sandpaper or emery cloth, you must not press very hard as you run the risk of tearing the sandpaper and at the very least, wearing out the grit permaturely. So hardwood is usually hard enough for the purpose.

Emery cloth is better as it was designed for sanding metals. The grinding medium used is more suited to metals, so it doesn't wear out as quickly. But it has not been easy for me to find the higher grit emery cloths, so I resorted to sandpaper (till I finally bought the Spyderco
Sharpmaker).

Hard to describe how 4000 grit paper feels. There is still some friction as you rub your finger across it, but it does feel quite smooth


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## BigHonu (Nov 14, 2002)

If you like the idea of using the sandpaper, head over to HandAmerican.com (I think that is the correct site) where they have some very good systems using leather, steel and a new one which uses sandpaper.


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## yclo (Nov 15, 2002)

While we're on this topic, I just got some 120, 180, 400, 600, 800, 1200 grit sandpaper.

What happens beyond the 1200 grit if I want a mirror finish on steel?

-YC


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## AlphalphaPB (Nov 15, 2002)

If you want a mirror finish on the steel, you should strop. Just use the card backing of a legal notepad, or a belt, and rub some jeweler's rouge into it. If you can't find jeweler's rouge, I've heard valve grinding compound will work, or you can even use nothing, which will take a little more time and effort.

Stropped blades look nice, and it helps get you a really nice shaving edge. It isn't always the best working edge though, so I tend to rough up the edge with a coarse ceramic stone after stropping.


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## Al_Havemann (Nov 15, 2002)

Really... The best way to maintain a razor edge is to learn how to use a steel sharpening rod. 

Even with the new, very hard blades like 154 CM and ATS 34, I've dressed an edge back to razor sharpness in less than a dozen strokes - maybe 15 seconds total so long as the basic cutting angle on the blade is good to begin with.

First, make sure you have a good quality steel - junk rods will damage a fine blade. A good rod costs about $20.00. Hinkle or Gerber both make good rods. And get a steel rod, not ceramic.

Start practicing with an older knife that still has a good angle on the edge. Hold the steel pointed away from you and try to "not quite slice" metal off the steel rod. It may take awhile to get the knack, but you will with practice. Use a smooth slicing motion without hesitation on the stroke. 

Some rods are diamond coated. It's best to avoid these since they put a "ragged edge" on the blade and strip metal away rapidly, poison to a fine, expensive blade like 154CM. 

Avoid ceramic rods as well. They need a different (harder to learn) technique and don't dress the edge as well as steel.

A ragged edge will feel sharp and cut pretty well but you can'r shave with it and it doesn't stand up all that well.

If the blade had good edge and just needs a touchup, use three strokes on each side. Do it twice with three, then two strokes each side, also twice, then one. Use moderate pressure, your not really trying to slice metal off the steel, just trying to get the correct angle and pressure. When you get it right, the blade will respond to the steel. 

Test the edge by slicing bits off of a piece of post-it note paper. When you get it right, the blade will slide through the paper with almost no resistance - and with a silky smoothlness that you can never get from a stone.

Once you learn how to steel a blade, you'll be qable to maintain a razor edge all the time.

To get the very last bit out of a blade, you can fine strop it with a leather strop after the steel. Beware though, a properly stropped blade will almost always be TOO SHARP!. A tiny slip and your headed for the hospital to get stiches. 

An edge that has been stropped is extremely fragil since there's very little metal to support the fine edge. Suitable for a razor maybe, but daily cutting chores will chew it right up.


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## whiskypapa3 (Nov 15, 2002)

4000 grit sandpaper feels like an old blackboard when you drag your fingernails across it.

Machinists use a piece of plate glass to back up Wet-or-dry paper while lapping steel parts.

When I was making knives my final "kiss" was on a leather strop charged with 1200 diamond compound (pulled away from the edge, you would be surprised how quick you can cut thru 1/4 in of cow). Rock shops carry diamond compound (5-8 bucks for a life-time supply).

Rember that grinding and honing are done by pushing the edge across the stone, like trying to shave a thin slice off the stone (paper).
Pull for stropping unless you want a multipiece strop..


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## Joe Talmadge (Nov 20, 2002)

What with all this take about stropping, 4000-grit finishes, and razor polished edges, here's something to keep in mind. A polished edge will be better at push-cutting, such as shaving the hair on your arm (the test you most likely do when you're done sharpening). But, a polished edge is absolutely miserable at slicing, which for some (many? most?) people is what the knife is more-often used for. For good slicing -- such as cutting rope, for example -- a coarser edge is called for. For slicing, a knife with an edge finished at 320 grit will vastly outperform a knife with a razor-polished stropped or 4000 grit edge, often by hundreds of percents, and that's not an exaggeration.

For my everyday carry knives, I like to put on an edge with a combination of grits. I razor-polish the entire edge, often going to 1200 grit and then stropping. Then, I take the first 1.5" of blade closest to the handle, and lightly run it over a coarse (less than 350 grit) hone. This gives me a razor-polished edge at the tip and belly for opening mail, cutting tape, etc., and leaves a coarse working edge at the back for slicing jobs.

BTW, I've started using sandpaper (wet/dry type) with the HandAmerican system for sharpening coarse edges, though as previously mentioned, I think sandpaper on a mouse pad would work just as well. When sharpening a convex edge, I use a spine-first/edge-trailing motion, the kind you would normally use for stropping, not the edge-first motion you would use for sharpening regular flat edge bevels.

Joe


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## mahoney (Nov 20, 2002)

Spidey82,
For endless debate of the pros and cons of sandpaper sharpening go to http://www.wwforum.com/index.asp
and look in the archives and in the articles for entries under "scary sharp", abrasive sheet sharpening, and sandpaper sharpening. 
Sharpening on sandpaper mounted on glass or wood works OK, although I prefer EZ-Lap diamond "stones" and Spyderco ceramic hones for hand sharpening. 
If you are just learning to sharpen, do yourself a favor and buy some kind of guide to hold the knife at a constant angle to the "stone". It will make a big difference in your results and once you learn the "feel" of keeping the knife blade at a constant angle as you sharpen, you can leave the "training wheels" off. Once you can consistantly get a nice flat bevel on both sides of the knife meeting at the edge you will have edges that are useably sharp, and you can move on to advanced topics like micro-bevels and convex edges, etc.


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## DonL (Nov 20, 2002)

There's been alot said regarding the quality of a cutting edge, but one aspect I haven't seen addressed yet is the _durability_ of the edge.

Regardless of the polish or coarseness of an edge, a 15° edge will simply not last as long as, say, a 22° or 25° edge. Now, we know it all depends on what we're actually using that edge _for_ which will determine the edge angle.

In my own use and practice, I'd rather have a slightly coarser edge with a slightly larger angle. I want to be able to use a knife, not feel like I have to touch it up on a frequent basis in order to have the blade perform consistently. Both the Lansky and Sharpmaker systems provide for the angle I'm looking for, and I've had good luck with them.


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