How to sharpen with sandpaper?

[Skyman]

Hello,

I procured 80 , 100 and some rough sandpaper along with a slab of glass to work with.What are the nuances and the process that is sharpening a knife with sandpaper?

Thanks

[Mack The Knife]

It's the same as sharpening on a stone. Google "sharpening knives on stones".

80 or 100 grit is good for starting your edge but you may want finer grits upto 600 /800 at the least if you want a slightly polished edge.

This is how I do a convex edge. You could use the same method for a v-edge except you will have glass or some other hard and flat backing under the sandpaper.

Mark your edge bevel with a permanent marker. This will show you where you are removing metal. Make necessary adjustment to ensure you are only working the edge bevel.

Maintain edge angle and do not use excessive pressure. Edge angle should be gradually raised as you transition from the flat edge to belly to point.

Sharpen on one side until you get a wire edge / burr all along the other side. Then repeat the same process on the other side.

Keep tally of the number of strokes per side and gradually reduce them till you come to one stroke per side and then do 5 or 10 single alternating passes per side. Then switch to the next finer grit and repeat the process.

[Skyman]

I went from rough to smooth grit and made the edge go from rough and blunt to smooth and reasonably sharp.The tip is sharp, but the knife isn't quite razor sharp.Can this be done with 100 grit? Local hardware doe not have any finer.

Will raising the angle give a sharper edge?

Thanks

[Mack The Knife]

If you are satisfied with reasonably sharp, then leave it at that. However, if you want sharper, then keep at it.

Did you raise a burr on the opposite sides or not? If not, your knife edge is far from sharp.

Whatever angle you choose, make sure it is consistent or the knife edge will keep going blunt - sharp - blunt - sharp usw.

100 grit, unless extremely worn, is incapable of putting a smooth edge.

Keep your sandpaper clean with an old toothbrush.

You can stick your sandpaper to the glass surface by wetting it, in a bucket of water for instance, and placing it on the glass.

[Skyman]

I went out and managed to find 320 grit.How well will this work? I haven't gotten a wire edge yet, will try now.Anything else i should know and thanks for the tips.

[Mack The Knife]

I went out and managed to find 320 grit. How well will this work?

You will find out for yourself.

Do not move to the next grit until you have formed and removed the burr from both sides as mentioned above. Maintain consistant angle and pressure.

[Skyman]

Okay, sharpened for 2 min now.The tip is quite sharp, the rest of the knife feels like a blunt razor.I used maybe a 20 degree angle.Even pressure and number of strokes.It still won't effortlessly cut paper.How to make it razor sharp, increase the angle or sharpen it some more? Formed and removed burr on both sides, thanks.

[Mack The Knife]

If you managed to get and remove a burr and the knife is still blunt, you are either changing the angle and/or using too much pressure.

Moving to finer grits will only give you a polished blunt edge.

Show me some pics of the knife edge and your sharpening rig.

[Mack The Knife]

Currently my knife has a V grind.I'm thinking of getting good at sharpening a v grind ( most cheap knives are ) then moving on to a convex grind.Can i change a V to a convex? Also can i polish the edge with plain leather?

Yes to both questions. The latter will take more time than if you were using a polishing compound but it will eventually polish the edge. You will be stropping the blade, so don't push the edge into the leather. http://www.knivesshipfree.com/pages.php?pID=4&CDpath=0

To change a v-edge to convex, exchange the glass backing for a mouse pad. I have even used a book.

In future, don't ask such questions via PM. Please use the forum.

[Skyman]

Will you be writing the guide then?

[Mack The Knife]

No. The above posts are sufficient. Perhaps you should try You Tube and find a video that helps.

[Skyman]

Not for me, for the forum.