When sharpening convex edged knives with SiC paper and a mouse pad, what grit to you usually use to finish up with? I know that I can get grit sizes down to 2500 from http://www.handamerican.com/ , but how does this compare to say an india stone? I am looking for a good cutting edge, somewhere between ideal for a push cutter and a slicer. Any thoughts are appreciated.
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SiC grit for convex edge
- Thread starter Quy4n8
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Smart-alek answer = as fine as you can afford.Richard Sommer said:
Real world answer = I usually don't go above 800 with silicon carbide since I usually end up stropping the rest of the way. But I have used 1200 and 2000 with good results. (require patience and a sensitive touch)
I'd stop at 800 grit and then strop. The 800 grit will leave deep enough scratches for a relatively toothy edge (compared to a fully polished 10,000 grit edge). The stropping will polish the teeth....so-to-speak.Richard Sommer said:
What most folks refer to as toothy, though, is really at about 400 grit. So, what you'll have is something in between (which is what I think you're looking for).
Bonus question. How is SiC different than Aluminum oxide. Does it cut faster, last longer, clog less?
I seem to remember finding pages about this, but not specific to metal work.
I use Al-O paper and it clogs quickly. It does a great job (I stop at 600), but I seem to go through a lot.
I seem to remember finding pages about this, but not specific to metal work.
I use Al-O paper and it clogs quickly. It does a great job (I stop at 600), but I seem to go through a lot.
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SiC clogs even quicker. It's really more for polishing. I don't buy SiC belts anymore.....throwing money out the window....there are other things that work just as well...
Get a sheet of SiC, tack it down to a piece of glass/plexiglas and you'll have a heckuva sharpening setup.
Get a sheet of SiC, tack it down to a piece of glass/plexiglas and you'll have a heckuva sharpening setup.
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With the EdgePro system and it's aluminum oxide stones Ben Dale recommends stopping at 220 grit for utility knives, and 320 grit for kitchen knives. So are we nuts for going to such fine grits with our knives? 
Has anyone ever found out an approx. grit value for the ultra-fine Spyderco Sharpmaker rods? Or the regular white rods and grey rods?
Has anyone ever found out an approx. grit value for the ultra-fine Spyderco Sharpmaker rods? Or the regular white rods and grey rods?
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The primary issue that I see is picking a grit that will blend well with the finish on your blade. When you strop you will change the finish on a broad area of your blade. This can look bad if you use a very different grit from the finish on your blade. If you go to an auto supply store (or some auto supply departments of discount stores) you should be able to find grit as fine as 1500, maybe even a little finer. Get a variety of grits. You probably don't need a grit finer than 600 grit for most practical purposes, but you may want to try a variety of grits in inconspicuous spots to see how it impacts the appearance of your blade. You may find that you want to go to the 1500 grit just for appearance.
Silicon Carbide is harder than Aluminum Oxide. It will wear less as you use it. This means that it will cut longer than the Aluminum Oxide, but it will leave more conspicuous scratches. The Al-O is a little smoother to start with and becomes a bit smoother as you use it. In particular the tallest grit in the Al-O will get worn off and the grit will become smoother and more uniform. The Si-C will not lose its high spots as easily and the grains will continue to be sharp and distinct for a longer time. For a smooth finish I like to finish with worn Al-O. For quick material removal I like the Si-C.
Silicon Carbide is harder than Aluminum Oxide. It will wear less as you use it. This means that it will cut longer than the Aluminum Oxide, but it will leave more conspicuous scratches. The Al-O is a little smoother to start with and becomes a bit smoother as you use it. In particular the tallest grit in the Al-O will get worn off and the grit will become smoother and more uniform. The Si-C will not lose its high spots as easily and the grains will continue to be sharp and distinct for a longer time. For a smooth finish I like to finish with worn Al-O. For quick material removal I like the Si-C.
WadeF said:With the EdgePro system and it's aluminum oxide stones Ben Dale recommends stopping at 220 grit for utility knives, and 320 grit for kitchen knives. So are we nuts for going to such fine grits with our knives?
I think polishing the entire edge at a very fine grit (say 600-1000) to make a smooth back bevel (or a convex back bevel) and then going back and putting a more aggressive grit on at a higher angle (edge bevel) seems to give the best performance. The micro-serrations on the edge provide the _rip_ and the mirror back-bevel gives the _slip_ through the material.
I am interested in some more aggressive paper, since the AlO seems clog.. it is cheap though...
on spyderco stones: (white fine 204= same as white fine benchstone etc.)
http://www.spyderco.com/forums/showthread.php?t=13424&highlight=grit
grit equvalency...
http://208.63.68.209/SharpenGuide.htm#Grit
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WadeF said:With the EdgePro system and it's aluminum oxide stones Ben Dale recommends stopping at 220 grit for utility knives, and 320 grit for kitchen knives. So are we nuts for going to such fine grits with our knives?
I was. Now, it seems I'm using Ben Dale's recommendation just from trial and error. Overpolished edges just weren't doing it for me cutting wise. After all, my Busse blades looked like they were finished with a 40 grit belt or something and still shaving sharp and my 1200 grit edges wouldn't do squat.
I was also going through a lot of the HandAmerica paper till I tried using it wet. Boy! What a difference a little water makes! My sheets are lasting 3/5 times as long it seems. Sometimes I'm a little slow reading the directions (WET/DRY on the back). LOL
Rob
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yes - the water is a great idea. oil, too.
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Daniel Koster said:
Haven't tried the oil yet. We have some stuff at work that's like a thin mouse pad. I cut it to fit the sheets and they write the grit on the back with white out. I use the water cause it dries out and I can keep all my different sheets under the workbench.
I assume you mean honing oil? I have another set at home and perhaps I'll risk the 'Wrath of Wife' and use my HandAmerican honing oil. Does it work/cut better? Does it screw up the adhesive backing? Although IIRC HA sheets are plastic backed. Perhaps not, I'll have to look. Also have to figure out a storage method to keep oil from getting me in (more) trouble.
Thanks,
Rob