Sharpening with sandpaper

J

JimStC

Joined
May 28, 2012
Messages
9
I am a new forum member and am just staring to collect knives to be used as tools on my farm and other purposes.
I have stones to sharpen my various blades, which range from machetes, hawks and knives.
My question relates to the use of sandpaper for sharpening and blade maintenance.
I have done some research and will still appreciate some advice.

Thanks,
Jim
 
Use wet/dry sandpaper and 3M polishing paper over plate glass. If you have very hard/tough steel you can use diamond film over plate glass.
 
I use a large paint stir stick from Lowe's, with leather (old belt) glued on, with various strips of wet/dry sandpaper, attached by spring clip. For what I've done, it serves my choppers, and my smaller blades.
 
I use stones for my flat and hollow ground blades and sandpaper for my convex ground ones. It works great, it's affordable and easy to carry (a big plus for me, I travel a lot).

Here's a helpful tutorial: http://brkca.com/convex.htm

For non-convex edges, just lay the sandpaper over something flat.

I use grits from 250 (for dinged up blades, really blunt machetes) up to 1500 (usually all it takes to keep a great edge on most small or medium knives). Unless I need to fixed a damaged edge or something like that, I rarely use the coarser grit sandpapers like 250 or 400. I finish up with a leather strop with some polishing compound.
 
I'd get a cheap Harbor Freight belt grinder if you're going to sharpen "machetes, hawks" (plural) and a few different grit belts. They don't cost anymore than a set of stones and in some cases much less.
 
I have tried several time, and I learnt that sandpaper was not really made to be blade sharpener. Get some cheap ceramic rod pretty much a better idea.
 
shqxk said:
I have tried several time, and I learnt that sandpaper was not really made to be blade sharpener. Get some cheap ceramic rod pretty much a better idea.
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There is a bit of a learning curve with using a freehand method and using sandpaper does work. What I have found works for me lately is taking cheap rubber sanding blocks from harbor and mounting them in my vise then placing my sandpaper on that. Also go with 3m wet or dry the cheap stuff doesn't work as well.

Gavko on youtube has some great tutorials on using sand paper to sharpen your knives.
 
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I use 600 and 1000 sandpaper and then polishing compound on a leather piece (all of them attached to glas). Works great. Sometimes I use an arkansas black stone in the end instead of polishing compound if I want a really flat edge.

/C.
 
Similar to what Tim616 stated, I use 400 grit wet/dry sandpaper and mouse pad to convex my fixed blades and finish off with black and green compound on leather strop.
 
Thanks to everyone who replied. I learned a lot and will add your recommendations to my sharpening routine. I find the leather strop quite interesting.
I just read a couple of articles on that technique. I had completely forgotten about that.
 
shqxk said:
I have tried several time, and I learnt that sandpaper was not really made to be blade sharpener. Get some cheap ceramic rod pretty much a better idea.
Click to expand...

Garnet sandpaper (the brown kind, used on wood) isn't made for it; not aggressive enough for abrading steel. The black/grey stuff (silicon carbide mostly, and some in aluminum oxide) is tailor-made for hardened steel and other metals. It's perfect for knife blades, and my favorite method, at that. :)
 
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When used edge trailing I find I have a very tough time removing wire edges, wind up doing a lot of work with a strop to finish it off. Capable of making very sharp edges, but they didn't last as long as my stone ground ones. When I stick it flat to a metal plate or use a bonded belt (cut down belts for a powered sander), and go edge leading, I find no functional advantage over a stone. I used to use it quite a bit until I learned to convex without it. Where weight is a consideration it can't be beat - otherwise I've come to prefer a hard stone. This is just my experience, YMMV.
 
Like it especially for thinning: no flattening, cheap and very fast. Depending on the steel, thorough deburring on a Chosera 2k followed by leather + Cr2O3. HeavyHanded is right about the wire edge issue with some steels. Try to perform some edge leading stokes as well when a burr has to be abraded, not just pushed to the other side.
 
Today I bought some 400 and 600 grit 3M Imperial wet/dry and some cutting oil. I already have a system to hold the paper in place. I have to say I am amazed. I have a pukko style knife that is horrible to get an edge. Not any more. So far I have sharpened 4 fixed blades and a Ka Bar Cutlass.
You guys got me out of the sharpening stone mental box I have been in for years. I use them too, but with the sandpaper, WOW!
Please keep the recommendations coming. For instance what are you using for the wet medium?
Also I am using a trailing stroke, which is the opposite of my stones technique. Any thoughts?

Thanks again,
Jim
 
A couple more questions. At what angle are you holding the knife? I am at about 25 degrees.
How much pressure on the knife during the trailing stroke?

Thanks,
Jim
 
JimStC said:
Today I bought some 400 and 600 grit 3M Imperial wet/dry and some cutting oil. I already have a system to hold the paper in place. I have to say I am amazed. I have a pukko style knife that is horrible to get an edge. Not any more. So far I have sharpened 4 fixed blades and a Ka Bar Cutlass.
You guys got me out of the sharpening stone mental box I have been in for years. I use them too, but with the sandpaper, WOW!
Please keep the recommendations coming. For instance what are you using for the wet medium?
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I always use the paper dry. It can be used wet (with water), but it's not absolutely necessary. Wetting the paper will help keep the swarf (metal particles) from clogging the paper. I usually just wipe the paper periodically with a microfiber towel (really grabs & collects the dirty stuff; works well).

Also I am using a trailing stroke, which is the opposite of my stones technique. Any thoughts?
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That's good, and what I'd recommend. You can use edge-leading, but ordinarily not a good idea if using soft backing (like leather or mousepad, for example). On hard backing, an edge-leading stroke can be effective. Keep pressure very light, to avoid cutting the paper (and it's good sharpening technique, anyway).

JimStC said:
A couple more questions. At what angle are you holding the knife? I am at about 25 degrees.
How much pressure on the knife during the trailing stroke?
Click to expand...

I prefer a lower angle, especially when convexing on a soft(ish) backing. Maybe like 15 degrees or lower (per side). Convexing on soft backing always results in a somewhat wider (thicker) angle, because of the tendency of the soft backing and paper to wrap around the edge bevel. You have more leeway with the angle if you're using the paper on a hard backing. Keep pressure as light as possible, to avoid rounding over the edge. Just enough to keep the blade in smooth, consistent contact with the paper, without bouncing or skipping. If you have trouble controlling the angle during the stroke, or it seems as if the blade is dragging too heavily, or if your hands seem to be getting excessively fatigued, lighten up on the pressure. Lighter pressure will lessen the severity & size of the burrs & wire edges, too.
 
JimStC said:
Which compounds are being used with the strop?
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For the most part, I've been using green (chromium oxide) compound, and occasionally I'll also use 1 micron diamond paste (DMT) or Simichrome polishing paste. Each on different strops, of course. I like the green compound on simpler steels like 1095 or low/mid-range stainless, like 420HC, 440A, 8Cr13MoV. The diamond paste works very well on more abrasion-resistant steels like S30V or D2, and the Simichrome really seems to work well on slightly harder stainless steels like VG-10, ATS-34 and 440C, though these steels also respond pretty nicely to the diamond compound.
 
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