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Fixing Blade Scratches

Discussion in 'Maintenance, Tinkering & Embellishment' started by Bladegunner, Aug 11, 2018.

  1. Bladegunner

    Bladegunner Gold Member Gold Member

    543
    Jul 28, 2016
    I got a bunch of scratches that run 90 degrees to the blade edge. I am thinking of removing the blade and sanding them out starting with 250 and going up to the highest grit I have sanding parallel to the blade or 90 degrees to the scratches. The blade steel is S90V is this feasible? Any tips, info or feedback appreciated.
     
  2. Bill DeShivs

    Bill DeShivs KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 6, 2000
    I would start with 400 grit, unless they are VERY deep scratches.
    Use a sanding block that matches the contour of your bevels.
     
  3. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    You're going to have a wonderfully fun time trying to hand sand S90V. CPM M4 is bad enough, Ive done that quite a few times, but I suspect S90V to be even worse. Even with 220 grit, a few strokes against the blade and the paper is killed. Makers that use S90V usually stop with a machine/belt finish and forgo the torture of a hand rubbed finish. Such wear resistant steels like that simply laugh at AlOx sandpaper. A better route is to use SiC paper, but only marginally. Like Bill said, if the scratches are deep, 400 grit may not be coarse enough. Heck, 220 grit may not be coarse enough!! Have fun with that.

    When doing hand rubbed finished, you are on the right track. Alternate scratch pattern every grit change, to ensure you are erasing the previous grit. But I'm giving a bit of caution here, you'll have a rough go at it once you get past 220 grit. If it proves to be a lot of work, what you might do is get your scratches removes with whatever grit that takes, preferably lengthwise (tip to tang). Then if you want a finer finish, forget about alternating scratch patterns and just stay in the same direction and go up to 400, 600, 800, wherever you want to stop.
     
  4. Bladegunner

    Bladegunner Gold Member Gold Member

    543
    Jul 28, 2016
    Sounds like I got my work cut out for me.....
     
  5. miso2

    miso2 Gold Member Gold Member

    Nov 19, 2014
    I am curious on how to do this.
    Would using EDM stones be more efficient?
    I have seen some makers (Southard, Gough, etc.) switch to EDM stones from sandpaper for satin finish.
     
  6. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    As someone who has never used EDM stones, I cannot comment on how much better they would be over sandpaper. Because they do break down with use, they may indeed be a better option than paper, especially on wear resistant steels. They break down which exposes fresh new cutting surface, compared to sandpaper where once it's done, it's done. I'm glad you reminded me, Miso2, as I've been wanting to give them a try with my knives. Rhynowet sandpaper works well, but the stones are an interesting option. There is a secret (that I've been sworn to) to finishing these steels by hand. I haven't tried that method yet anyway.
     
  7. Bill DeShivs

    Bill DeShivs KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 6, 2000
    I use cheap waterstones often when refinishing blades to take out pits.
    They are not particularly good for final finish.
     
  8. Wowbagger

    Wowbagger Basic Member Basic Member

    Sep 20, 2015
    Best tactic is to buy another exact knife . . . put knife in safe . . . put scratched knife in pocket.
    Enjoy scratched knife because you are now free to relax and just enjoy using the knife.
    Enjoy the pristine knife for when you want to do that.
    One knife sort of fixed and sort of rescratched in use after you fix it . . . and or later scratched while sharpening is going to just be frustrating in every way . . . dude.
     
  9. Bladegunner

    Bladegunner Gold Member Gold Member

    543
    Jul 28, 2016
    That's a option other than its a $650 knife and don't have that much extra scratch laying around for a safe queen.
    Not sure if trying to fix it might make it worse than it is now.
     
  10. Bill DeShivs

    Bill DeShivs KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 6, 2000
    Perhaps it would behoove you to pay a professional to do it.
     
  11. miso2

    miso2 Gold Member Gold Member

    Nov 19, 2014
    I have done the DIY satin finish on my $100 knife to erase scratches.

    [​IMG]


    It took a while with sandpaper but worked.
    The only thing I don't like about the result is the plunge line.

    If you want a perfect result, it may be better to send it someone like Josh at REK.
     
  12. Bladegunner

    Bladegunner Gold Member Gold Member

    543
    Jul 28, 2016
    That would be the smart thing to do but I rarely do the smart thing. I really prefer to do things myself I find thats the best way to learn. I guess I will practice on a cheap knife. I did do a high polish finish on a small kitchen knife that came out fairly well but not a super steel by any means.
     
  13. drail

    drail

    239
    Feb 23, 2008
    Tip: wrap the sandpaper around a thin wood paint stick and use it like a file. Paint stores will generally give them to you. This keep your cut nice and flat.
     

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