convex supplies

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bennyG19

Joined
Sep 22, 2007
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say i want to go to wal mart later today and buy some supplies to try my hand at convex sharpening... what should i buy?

I'd like to give it a try but not go broke in the process.
 
go to the auto section and look for sandpaper, the one near me carries 600, 800, 1000, 1500, and 2000 grit wet or dry. If you have a mouspad around you're good, just put the paper on top of the mousepad and VIOLLA!!!! you've got yourself a sharpening system.

If your edge is not too messed up these grits can take you to a nice polished, really sharp edge. It's what I used on my dumpster mutt,

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it can cleanly slice a tomato thin enough to see through, and it's 5/16" thick

good luck and enjoy!!
 
Get a mousepad, some 500 grit carbide paper and some 1200 grit carbide paper. Put the 500 grit over the mouse pad and sharpen the knife as if you were stropping it. After you've got the edge where you want it, polish it out with the 1200 in the same manner. The paper comes cheap @ Harbor Freight. If you have a spare mousepad you could get your whole setup for under 10 bucks :D one sheet of the wet/dry carbide paper goes a long way, especially after you get your edge right and just have to touch up!

Happy hunting!
 
I should point out that when you get to the point where you are putting the finishing touches on the edge that you should use lighter and lighter strokes over the paper, otherwise you could round over the edge.
 
right on guys, thanks for the help. there's a harbor freight on the way to wal mart so i might just get everything i need there. what do i use to keep the sandpaper on the mouse pad? or do i just lay it on there and leave it alone?
 
Keep your paper or emery cloth, (whichever you decide to use, (I use emery cloth til I get to the really fine grits), stored so it lays flat. That way when you lay it on the mouse pad it's flat and will stay in place and not roll up on you and move around much. You will have to adjust the paper from time to time to get lined back up but it's not a big deal.
 
just got back from the store. i got a 10 pack assortment of 9"x11" wet/dry silicon carbide paper from harbor freight for $3.59 with 2 sheets 220, 3 sheets 500, 3 sheets 1000, 2 sheets 1200. i went to walmart and got a mouse pad for $2.70, 5 3"x9" sheets of 2000 grit wet/dry for $3, and an assortment of thumbtacks (my solution for holding the paper on the pad) and clips for $1.89. total for the day...about $12. i could have gotten the thumbtacks cheaper except it was back to school mania and the 88 cent packs were gone. i'm going to roll up the cover of my wife's "Interior Design" magazine for a strop. I've used that before and split hairs with my Mora, so it should work for this method, too.

time to try this out, wish me luck.
 
bennyG19 said:
right on guys, thanks for the help. there's a harbor freight on the way to wal mart so i might just get everything i need there. what do i use to keep the sandpaper on the mouse pad? or do i just lay it on there and leave it alone?
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If you're going to Harbor Freight, pick up their 1x30 belt sander (about $40, IIRC). then get an assortment of belts, including a leather stropping belt, from Lee Valley (.com), and you've got yourself the primo convex sharpener!
 
i tried it on three knives and the results were not the greatest. on my Vic Cadet, it is now sharper than before, but that's not saying much.

my old timer that i'm trying to rehab is fairly sharp now, but not great.

i also tried it on my Case CV peanut, and it is duller than when i started. it was shaving sharp when i got started, now it's not. i went through all the grits i had...220, 500, 1000, 1200, 2000. about 25 strokes on each side on each grit. i didn't push too hard but it didn't seem to work the greatest. i'll probably give it another go later on tonight during the NASCAR race. any more tips for a convex first timer?
 
That's what happened to me the first time I tried it. I learned that as soon as I got the general shape I wanted for the edge, to ease up and not put too much pressure on the blade. Once you get to 500 then 1000 start easing up to the point that you are barely percieving that you are touching the paper. Also change from the mouse pad to something more firm to prevent rounding over the edge.
If you really want to start getting sharp fast and easy take Grampa's advice. Those sub micron belts and leather strop belts will have you whittliing hair in no time.
 
well the way i learned it was, your actually rounding the existing edges of the upper part of the bevel i.e. \/ the top parts of the bevel. so for it to do this it may take some time on the 220. i went untillo i got a burr on the 220, witht he spine of the knife at a low angle. do this then do the other side, untill the burr transfers, then do maybe 8 per side till you can feel the blade almost glide across the sandpaper. then move up to the next grit, and jsut do alternating strokes or a couple 8 per side then switch. continue untill your all the way through the 2000 grit. should be hair popping when your done. i hope this helps.
 
i went back to the tried and true sharpmaker method on my peanut and cadet and they are hair popping sharp again. i'll try the convex on another knife another day. i can get great edges with the sharpmaker, but i'd still like to learn to convex. i ran out of patience today.
 
so how long does it take to convex a blade that is not convex? do i just use the 220 grit for a long time before moving on?
 
The blades you are trying to convex aren't "super steels" and are pretty thin, so no you shouldn't have to use that much grit for very long at all. You just want to remove the upper shoulder of the edge and shape the new edge to convex.
I think you may be holding the knife at too high of an angle and may be rounding over the edge at some point in your process.
 
If you're going to use a mousepad for backing for your abrasive cloth/paper, you have to keep from using too much pressure, and don't let the angle of the blade to the abrasive get too steep, otherwise you risk rounding the edge.

Personally I prefer using a rubber sanding block, the kind used for auto body work, instead of mousepad, the greater stiffness of the rubber let's you use more pressure and you don't have to be quite so careful about angle control. Or sometimes I just use a regular benchstone ... there are many ways to produce or maintain a convex edge, in fact when most folks sharpen freehand on a stone the edge is at least partially convex.

Convex sharpening is probably the easiest, most natural type of sharpening, the trick is not to make it too complicated and wind up outsmarting yourself. :) Also it's no sin to use a Sharpmaker or fine hone to apply a microbevel in order to get that super-sharp final edge.
 
Use a sharpie to mark the edges and then do the mousepad/sandpaper. You can tell if you are hitting the the edge properly with your stroke. And like everyone else here says, use light pressure. A tip from Siguy to get that last bit of sharpness and for touchup is to use some mildy stiff cardboard loaded w/ compound (tripoli, chrome dioxide or whatever you can find at hardware store) and use it as a strop. Cardboard siguy sent me was about 1.5 by 8 inches long. Again watch the angle by using the sharpie. I was coming in too shallow and missing the edge.
Of course if you have a lot of knives to sharpen or you want to reprofile edges, than Grandpa has the key. Just got a harbor freight 1 x 30 belt sander, some sanding belts and a leather strop belt from Lee Valley w/ chrome dioxide compound and it is amazingly effective and lots of fun. It was gratifying to get some even chronicly dull profiles re-beveled and then shaving sharp.
Oh if you're gonna use a belt sander/power strop always finish w/ a hand strop as it will take off the wire edge and leave it truly sharp and not just short term (few cuts) sharp when the wire edge comes off.
 
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I convexed a few of mine very nicely. I thought I had it figured out. Now I have screwed up the last several that I tried. I think I am rounding off the edge.
 
udtjim said:
I convexed a few of mine very nicely. I thought I had it figured out. Now I have screwed up the last several that I tried. I think I am rounding off the edge.
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Maybe too much pressure on the mouse pad/sandpaper? Of course we both know sending knives to Siguy is a winning propostion to set up great convex edges which could be maintained well w/ cardboard or leather strop and compound.
 
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