'Homemade' whetstone

[fenderjaguar]

today, i was walking through a valley, when i found a cheapo knife. looked a bit like a kitchen knife, really. but i think it must've been some sort of survival, because it had holes dotted up near the edge of the blade.

i then looked round to see a very flat piece of sandstone. at least i think it was sandstone, anyway. the surface was nearly completely smooth. so i took both items down to the river, dunked the stone in for a few minutes, then layed it down on the ground infront of me. i began sharpening the knife. it's only the second time i've ever tried to sharpen. i tried sharpening on my uncles whetstone, but i think it is intended for chissels and suchlike. all knowledge i'd gained came from the sticky threads in this forum.

after 20 pushes on either side of the blade, the stone looked quite smooth. i continued and occasionnally washed both the stone and the blade in the water. the stone was then comletely flat and smooth andthe knife ended up quite sharp.

at the end of it, i was fairly happy, to say that the knife was nothing more than a blunt piece of metal when i'd found it. i may even use the stone to sharpen my mora bushcraft knife. it was only cheap.

what do you guys think, is sandstone suitable for this kind of thing?

it was just nice to be able to get something out of nothing like that. ah well....

 

[Longstrider]

If you are not looking to make your edge too finely honed or smooth I suppose this could prove useful. In a survival situation it would probably be the best, if not the only way to re-sharpen your edge tools if you had not taken a recognised sharpener with you.
Problems that you are likely to find with using a sandstone are that it can have very irregular grain size in it, it will probably wear very quickly and it will probably not be properly flat when you begin using it. The irregular grain size will lead to deep scratches along the edge and on any piece of the blade that you grind with it. (think of what steel would look like if you filed it with a file that had a few teeth that were bigger than the rest and you'll see what I mean) Starting with the stone being not truly flat will mean that you grind away some parts of the edge unevenly, effectively using your knife as a dressing tool for the stone.
The sandstone is also likely to be pretty coarse in its make-up. This will never give a nice smooth edge to your blade, but will tend to give the cutting edge a rough, toothy finish. This can actually be more effective for certain tasks than a well stropped and polished edge but it's not something I'd like to do to one of my own blades as a rule.

A lot of the sharpening stones we pay good money for are actually natural stones. The GB axe stone is very sandstone-like itself. The thing with these is that they are chosen and sorted with great care to ensure that the grit size and consistency are as regular and even as possible to avoid the problems listed above. If you have found a piece that does the job well and keeps your knife as sharp as you want it to be, well done you !

 

[sam_acw]

Chalk is a good fine abrasive. You could use a lump of it as long as it didn't have any fossils inside it or just use it as an abrasive powder.
I've also cleaned gun barrels with wood ash and water