Roughen Carbon Fiber?

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Bolstermanic, Feb 19, 2021.

  1. Bolstermanic


    Mar 13, 2007
    I bought a sheet of woven carbon fiber to make scales for a Spyderco Mule, but it is soooo slick, I don't think it will make good scale material as is. Can CF be soda blasted, bead blasted, or stonewashed? I need to get the surface grippier.

    PS: I did try to post in the knife makers forum but I don't see anything that subscription only or something?
  2. john april

    john april KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Feb 27, 2006
    hi, no its not a subscription. i think anyone can post there. i have not seen roughened carbon fiber, but i would be concerned about the fibers getting in your skin, like fiberglass insulation will. i guess that depends on how rough the surface is. i use knives with shiny buffed handle material, they do not seem slippery.
    Dawkind likes this.
  3. Dawkind

    Dawkind Platinum Member Platinum Member

    Apr 3, 2000
    Use Lightening Strike CF, don’t smooth off the ‘wiring’ and it’ll be plenty ‘grippy’....;) :D
  4. Bolstermanic


    Mar 13, 2007
    Thanks for the heads up. Unfortunately purchased a slab already but... it's just money, right? I think I *may* try a soda blast. I see people reporting they bead blast CF to good effect, and a soda blast should be even gentler...I hope...No, I don't want fibers stuck in my hands, no sir...
    Dawkind likes this.
  5. brownshoe

    brownshoe I support this site with my MIND

    Sep 6, 2002
    I have a Zieba with carbon fiber that's not smooth. It looks like it was countoured with something that left shallow grooves.
    Dawkind likes this.
  6. Bolstermanic


    Mar 13, 2007
    My post was moved to the knifemaker's forum, and now I have access to the KM forum as well...woohoo!

    Any opinions on soda blasting smooth CF?
  7. Daniel Carraher

    Daniel Carraher KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 30, 2018
    Have you done any contouring or sanding to the surface?
    Hengelo_77 likes this.
  8. navasky


    Dec 7, 2009
    You can sandblast it to bring out the texture just like g10 but you will lose some of the cool holographic look. You can also buff it after sandblasting to bring back a little shine. I will post a picture later if I can find a sandblasted piece lying around.
  9. C.Kelly Custom Knives

    C.Kelly Custom Knives KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    May 16, 2018
    He was kidding about the Lightning strike CF :D. Lightning strike CF is annoyingly "prickly" until you make sure all the little metal fibers that stick out of it are completely sanded away.:D

    My 2 cents... CF is among a group of handle materials that is best used polished or close-to polished. Once you bring the texture/finish grit below about 800 it starts looking a lot like G10 and at below 400 grit it's not all that distinguishable from any other black handle material. The main appeal of CF is the look of the woven or shredded pattern, and that look is accentuated by polishing it and bringing out a 3-D depth and visual movement within the pattern.

    I'm certainly not suggesting you shouldn't modify your knife to your liking. By all means, make it the way you want it. If you're going to sand the handle yourself, WEAR A RESPIRATOR. CF fibers dust gets beyond tiny and in-beds itself in your lungs. It's nasty stuff that you don't want to breathe.
    Hubert S. and Scaniaman like this.
  10. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    The dust also sticks to EVERYTHING in the shop and on you by static electricity. It is super nasty. It makes G-10 seem downright friendly ( which it isn't) I don't use CF unless it is the only thing that will work.
    I would guess that I have used several hundred pounds of micarta, and less than two ounces of carbon fiber.
    Ken H> likes this.
  11. fishface5


    Feb 3, 2001
    Another approach would be to add a grooved pattern to the scales with a small file and then polish the grooves to bring out the cf pattern. Tons of design possibilities and added grippiness.
  12. Nick-D


    Apr 17, 2017
    It's not really slippery even at a high polish. I would polish it out and use it, then if your not happy with its grip, use some sort of surface treatment.

    It's really does look its best with a nice fine polish on it. Really brings out the 3d in the fiber
  13. Bolstermanic


    Mar 13, 2007
    I needed this warning (and the others in this thread). Here's the CF sheet and the mule I was going to put it on...want to make a light blade for backpacking... but the horrible reputation of CF makes me think I should save a CF project until I get more experience under my belt. The last thing I want are fibers poking me in the middle of a backpack trip.

    And, honestly, the CF wasn't as lightweight as I was expecting. Now I'm looking around for a piece of FRN or FRCP - those are light weight, no?

    Natlek likes this.
  14. Alex Topfer

    Alex Topfer

    May 1, 2019
    Whatever you use for the scales of that the weight will be in the blade and tang. Get a pukko blank (or similar) and make the handle out of leather, light wood, maybe carbon fibre wrap? Or a block of plastic if you need it completely water-proof.
  15. Hubert S.

    Hubert S. Gold Member Gold Member

    Dec 14, 2019
    Composites are light weight for their strength, particularly when compared to metals... Depending on the amount of resin, carbon fiber sheets are maybe about 50% heavier than water, nylon with 30% glass is just a bit lighter. There are other materials that are much lighter and can be used for knife scales. Most woods float, paracord is 0.071 oz/ft. With the mule you are close to 3oz to start. If you went with a cord wrap, you could skeletonize the tang a bit more aggressively and lose some of that. But you'll likely end up a good bit heavier than 3oz if you count the sheath. For lightweight backpacking, folding knives seem to be a better option to me. There are lots of models in the 3oz range and some even below an ounce. You're not going to split firewood with the ultralight ones, but if you only need a knife to maybe cut a guy line or open a plastic food pouch, you can save a lot of weight. If it were me, I'd put some nice looking scales on the mule and look for a lightweight folder to take backpacking.
  16. Daniel Carraher

    Daniel Carraher KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 30, 2018
    No fibers are going to poke you. The CF is shiny and slick because it hasn’t been sanded or contoured at all. If you wear a respirator that CF will work perfectly fine.

    Were you planning on not having to sand the material and leaving it flat?
  17. Bolstermanic


    Mar 13, 2007
    Hubert: Thanks…Skeletonizing the tang more would be ideal. Not certain how to accomplish that without heating the knife through drilling/grinding, it’s Rc 62. Ideas?

    Regards weight: Correct. The mule is 2.8 oz naked. Your assessment of a folder is spot on (you must be a backpacker also) but the knife is my weight “splurge” since I’m dead-set on a 3.5” fixed blade with full tang, for the purpose of batoning if it comes to that. Have carried folders in the past and found myself wishing for a sturdier option so upgraded to a White River M1 Backpacker (3.0 oz sheath included) but I’d really prefer a longer blade.

    Daniel: Plan was to radius or chamfer the edges, that’s all. It’s thin CF because I’m trying to keep the weight down. I don’t care about looks; I’d use balsa wood if it were sturdy enough!
  18. Hubert S.

    Hubert S. Gold Member Gold Member

    Dec 14, 2019
    I have not been out backpacking in a while, but when I used to go more frequently I tried to save as much weight as possible.

    You could use a Dremel with a small cut-off wheel to cut out some of the material and then smooth it with the small grinding stones, sanding wheels or maybe carbide burrs.
  19. Daniel Carraher

    Daniel Carraher KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 30, 2018
    Just sand the top surface (only have to remove minimal amount) and it won’t be shiny or slippery. Scales should be plenty light when cut down to size.
  20. SS369


    Nov 29, 2015
    Add chamfered holes. Could even vary the sizes around the scales according to looks and ergonomics desired.
    Hengelo_77 likes this.

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