Using Sandpaper to Sharpen Knives

J

jcmv4792

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Mar 11, 2014
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How long does a strip/sheet of a certain grit usually last? For example if I use 8x2" strips of 320grit, 600 grit, and 1000 grit sandpaper, will that be enough for one knife, or will I need to go through several sheets?

Is 3m wet or dry a good brand or are there brands specifically made for sharpening metal?
 
1 sheet is good for 3-5 knives worth of sharpening. Sandpaper works quite well, actually.
 
Rennd said:
1 sheet is good for 3-5 knives worth of sharpening. Sandpaper works quite well, actually.
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Good to hear. Which brands sell sandpaper good for sharpening knives? Is 3m's aluminum oxide sandpaper better than the regular ones they sell?
 
Don't forget a pink eraser to clean the paper often to remove the metal from the paper, it extends the life a lot.
 
jcmv4792 said:
How long does a strip/sheet of a certain grit usually last? For example if I use 8x2" strips of 320grit, 600 grit, and 1000 grit sandpaper, will that be enough for one knife, or will I need to go through several sheets?

Is 3m wet or dry a good brand or are there brands specifically made for sharpening metal?
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Gator brand works better than 3M. If you take care of the sandpaper it will last a lot longer than many might believe. The key is to use light pressure, clean the surface when it loads up using an eraser or crepe rubber, and use a progression that makes sense - don;t try to do a ton of work with a small abrasive size. An 8"x2" surface can easily do a dozen or more knives if properly used. I have tossed one half sheet in the last 5 months or so.

Too much pressure or continuing to grind away when its loaded up (or both) will kill it very quickly - 1 session or less. This is an oft overlooked aspect of sandpaper sharpening.

I sell a block through the link in my signature that has a bunch of video links showing good practices for sharpening with sandpaper. Application is universal to all sandpaper sharpening, you don't have to buy my block (or even be interested in buying it) to learn some useful tips from the videos.
 
HeavyHanded said:
Gator brand works better than 3M. If you take care of the sandpaper it will last a lot longer than many might believe. The key is to use light pressure, clean the surface when it loads up using an eraser or crepe rubber, and use a progression that makes sense - don;t try to do a ton of work with a small abrasive size. An 8"x2" surface can easily do a dozen or more knives if properly used. I have tossed one half sheet in the last 5 months or so.

Too much pressure or continuing to grind away when its loaded up (or both) will kill it very quickly - 1 session or less. This is an oft overlooked aspect of sandpaper sharpening.

I sell a block through the link in my signature that has a bunch of video links showing good practices for sharpening with sandpaper. Application is universal to all sandpaper sharpening, you don't have to buy my block (or even be interested in buying it) to learn some useful tips from the videos.
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I actually sent you an e-mail about your block. I may be interesting in buying one soon.

After using an eraser on the sandpaper do I need to worry about the left over rubber on the paper? Does it come off easily?
 
jcmv4792 said:
I actually sent you an e-mail about your block. I may be interesting in buying one soon.

After using an eraser on the sandpaper do I need to worry about the left over rubber on the paper? Does it come off easily?
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Just brush it off with a swipe of your hand. If you watch any videos of folks using waterstones, picture the eraser doing the same as a splash of water. "Stone" loads up, you clean it off. This also improves the quality of the grind itself - requires less pressure to cut the steel, less pressure to remove the burr, longer life of the wet/dry.
 
Sorry for all the questions, but I'm trying to learn all I can.

Is sandpaper grit the same as JIS grit?
 
This is the stuff I use - is available right at my local ACE

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There's a sticky at the top of the page:
http://www.bladeforums.com/forums/showthread.php/856708-The-Grand-Unified-Grit-Chart

Pretty sure most of the wet/dry will be ANSI.

Edit to add:
Don;t want to sound like I'm panning the 3M paper, their lapping films are great, and the wet/dry works well too. It just doesn't seem to last as long. I haven't tried any of the Norton papers - they have a non loading paper I'd like to try - isn't waterproof but might be great for sharpening.
 
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jcmv4792 said:
Sorry for all the questions, but I'm trying to learn all I can.

Is sandpaper grit the same as JIS grit?
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Sandpaper sold in the US is usually graded to FEPA-P (look for grit labelling like 'P400' on back of sheets) or ANSI standards. The 'sticky' referenced earlier (Grand Unified Grit Chart) will lay out the grit specs of each, as well as for the JIS standards usually reserved for waterstones.

(BTW, the 3M and Norton papers work well; I use these. Haven't yet tried the Gator brand though.)


David
 
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Sandpaper and a really thin mouse pad is all I have been using for a while now. I can get pretty good life out of my paper. Go slow, use light pressure, work up the burr, flip and repeat. I finish with a couple passes on a ceramic stick and then strop with jewelers rouge on leather.
 
I use sandpaper to sharpen recurved knives, not as good as water stones but it works.
 
jcmv4792 said:
How does lapping film compare to sandpaper?

http://www.japanwoodworker.com/category/13516/sandpapersharpening-film.aspx
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Am not sure what the abrasive is with those sheets. Have used 3M aluminum oxide lapping films and their diamond lapping films. Both work very well and can be used with water or soapy water. Aside from the abrasive mineral, that's the biggest difference - lapping films really should be used with a liquid to suspend the swarf. Is also a bit more difficult to use a fore and aft stroke without nipping the film than it is on wet/dry though it can be done with practice.

IMHO unless needing diamond to work vanadium carbide steel to a high polish, the silicon carbide wet/dry works just as well at lower finish, and a sheet of baking parchment or regular writing paper with compound works as well at higher levels of polish.
 
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