Does kydex scratch knives?

It occurs to me there might be another mechanism at work here. When it comes to satin finished or brushed surfaces, the Kydex might simply be burnishing the micro scratch pattern in the steel. This wouldn't require the Kydex be harder than the steel, just that it be hard enough to effect the surface finish. This would explain how clean Kydex could mar a piece of steel, and only become more aggressive as the Kydex itself began to accumulate scratches etc. Also explains why many of the Kydex scratches I've observed tend to look a little spread out, and not thin, distinct scratches like what would be common from tiny pieces of grit. Note the scratches in Nuskinner's pic that look somewhat broad, these are exactly the kind of scratches I'm familiar with.

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I dont know...But I can say for a fact that it will(and it may be the Kydex its probably a small piece of dirt or dust the gets inbetween the kydex and a gun though) scratch a guns finish..Ive had it scratch my Previous EDC Glock 23 and my current EDC Ruger SR9c . all I use are pretty much Kydex Holsters(RM low Rider Kydex I used with the Glock and Crossbreed super tuck with the Ruger) both got scratched at the contact points from the kydex..as some said I dont think the kydex its self is really enough to scratch it BUT just a little piece of debris in there thats probably what does it.
 
It seems both could be possible. I have had numerous kydex sheaths for knives and never had this problem. The sheath that left this damage was a custom job and apparently not a very good one. I know it was not an issue with the knife since it went new from the box right into the sheath. When my eBay dispute resolves and if the seller doesn't want it, I will pry it open and send a pic.
 
It's all in the process of making the sheath. It was mentioned already, the kydex shouldn't touch the blade. This is accomplished by layering tape on the sides of the blade prior to pressing to form. I've found that the best method is to do 2 layers of masking or carpenter tape on each side, but an inch from the tip just do one layer, and only tape the blade, not the guard, as this is the area that locks down. This should give enough clearance at the sides while giving a slightly snuggier fit at the tip to prevent rattles, but if it traps the top of the handle as it should there should be no issues.
 
Here's what I've noticed - in some respects it doesn't come down to how well the sheath is made so much as what the knife is used for. If its a working knife and you're doing a lot of one-handed retrieval and resheathing while doing active work, the blade is going to make contact with the throat of the sheath and it will get marked up. With practice one can do sort of an abbreviated method similar to sheathing a katana, where the spine makes most of the contact, but this isn't always possible.

FWIW, I've managed to line all my Kydex with a thin layer of waxed leather. This not only prevents scratches, but keeps my carbon knives from rusting, while keeping the good retention and low profile of the Kydex.
 
heavyhanded, did you ever do any more testing on kydex dulling a blade if the edge rubs the kydex ? i think the leather is a good idea. where do you get leather that thin?
 
You need to be specific about the difference between a scratch mark and a rub mark. A very narrow point of contact between blade and kydex can produce rub marks that look like scratches. To avoid most of these, wrap the blade in several turns of tissue paper before using it to mould the sheath.
 
richard j said:
heavyhanded, did you ever do any more testing on kydex dulling a blade if the edge rubs the kydex ? i think the leather is a good idea. where do you get leather that thin?
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I never went past the limited testing described above, and I encourage anyone else to try it and see what happens. Maybe they'll have a different outcome. Based on that and other observations I can say for certain the Kydex will put a "scratch" through a grind pattern or satin/brushed finish, its not a mark that can be washed off. I first became aware of this on a TOPS knife I'd stripped the traction coating off of. Back when I used to spend some time looking at edges under the microscope, these caught my eye immediately. I then began to take a closer look at the scratches appearing on the blade itself. The only pattern was where they were making contact with the sheath when being taken out/put back in. It came as no surprise to me when my Bark River necker started showing some scratches just as soon as I started using it.

Whether this is a scratch in the classic use of the word or some sort of burnishing, the end result is the same. Not so sure regular Kydex can dull a blade, but if it keeps rubbing right off the apex at a shallow angle it could certainly have some effect.


I just use scrap leather, some of it came from an old jacket I used to wear back in the mid/late 80s - it was just too groovy for me to ever wear again:) I don't do anything more fancy than rub some canning wax (paraffin) into the leather and melt it in with a hot air gun. Repeat a few times till it doesn't suck it up very well anymore. Shape to fit the inside of the sheath (the wax helps it hold its shape and makes it fairly rigid), smear the smooth outside with Goop, insert into sheath (making sure it'll accommodate the knife/handgun) and pack with foam or small rags till it dries. After it dries and if necessary, gently heat the sheath with a hot air gun if it has become too tight. It helps if the sheath has screws instead of rivets, you can spread it a bit to get a better fit and run the leather right out to the outside edge, but can be done either way. I've made a few from scratch this way and its a great way to EDC a carbon blade - they will not rust even at the hottest, sweatiest time of year. You can also get good retention on handle shapes that don't normally work well with Kydex, like puukkos, Mora classic, etc.
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Not the prettiest, but they work great.

Have to add that I originally started doing this to my handguns years ago - discovered some other custom makers were already doing so but not widely known. Holster wear diminishes considerably, better rust resistance, you get smoother retention and a quiet draw - what's not to like? Adopted it for the TOPS knife mentioned above, and I'd swear it holds its edge longer for it - maybe the waxed leather keeps it from oxidizing along the edge, but I have my own ideas...
These days I just line my Kydex SOP and have zero problems - doesn't surprise me at all that some other people have issues. Not sure what to make of folks that claim no problems - maybe they're using a high polish on the blade, or are more careful than me when taking it out/putting it back. I can only comment on my own observations and they've been pretty consistent. I've also been known to get stuff wrong too...


BTW Richard, glad to see you back on the forum.

HH
 
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i have some thin suede that would work great to line a sheath. i think i'm going to cut some up and give it to my buddy so he can try it on some of his own knives to see if it will work.

i'm slowly getting to where i can move around a little better. my incision (which is around 8" long) is causing me some discomfort and making it hard to stand up straight for very long. i'm anxious to get back to sharpening but i was told to take it easy until i heal up more. i dont think it would be fun to split myself open :D
 
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