Kydex sheathing: a possible fix for the moisture issue?

Jim March

Jim March

Knifemaker / Craftsman / Service Provider
Joined
Oct 7, 1998
Messages
3,022
The advantage of the classic sheath over kydex is in moisture wicking. When I designed The Outsider's rig I didn't care because it's ATS34 steel, but this is high carbon.

What I'm thinking is, how do we embed moisture protection and/or "removal" (wicking) into the kydex sheath?

First thought: a wooden insert strip? To have wood contact an unsharpened spine would be simple and wouldn't add a lot of bulk, but I have a hard time imagining it pulling the water all the way from the edge.

Second thought: I was wiping down my new baby with a generic silicon-impregrated "tough cloth clone" from a local gun shop, and noticed the price: less than $2. Hrmmm...stitch it INTO the kydex sheath, or better yet sew it onto the kydex before folding the kydex over the blade during the production process?

HMMMMmmmm...that would mean heating the toughcloth to at least 300f, dunno what that kind of heat will do to the cloth. I can snip off a small bit and fire up the over tomorrow and find out! If the silicon evaporates more can be sprayed onto the cloth, especially if it's my type of "side-draw" that would leave the interior more open to spray treatments. I have some very heavy waxed thread that can be used to "stitch" the cloth onto the kydex through a bunch of small-bore holes in the kydex.

Now, perhaps these two methods can be combined? Let the cloth pull the water off the faces and back to a wooden spine?

Can anyone think of any other liner type that would allow fast drying after an outdoor drenching? Remember, as a biker doing open-carry I could end up forcing enormous amounts of water into the sheath at 80mph. Four hours of that kind of treatment didn't affect the untreated ATS34 at all, I was quite pleased...but more thought will have to go into a Khukuri rig under the same circumstances.

What about a thin layer of teflon sheet grafted into the sheath, try and let the water just run out faster? Naaa...gotta punch holes in it and run *some* sort of thread and those will retain moisture.

Ideas? Kydex has mostly been applied to more modern steels, we're on some new ground here.

Jim March
 
Can't think of an answer to the sheath issue.
I can highly recommend Corrosion-X to treat Khukuris, guns, whatever against corrosion.
 
The ideas are sound, Jim, but sewing and wahatnot is impractical for Kydex, at least unless you have some kick ass equipment! The heating is almost a non-issue, though. Kydex forms just fine at temps as low as 200 degrees, and perfect is probably 225. At least that's what I've found.

------------------
My Custom Kydex Sheath pagehttp://www.geocities.com/CollegePark/Lab/1298/knifehome.html
Palmer College of Chiropractic
On Two Wheels
 
I like the way Jim's mind works. You will find the right way, Jim. Just keep the wheels spinning.

Uncle Bill
 
Chiro, if you take a standard drafting compass you can make a whole string of little "pinpricks" in the Kydex, evenly spaced around the edge. You can then come along with a small drill bit and do a string of real holes, which in turn would be how you sew the tuff-cloth or whatever onto the kydex.

Now, one problem I can see is the tuff-cloth "fraying". You could take the edges and "fold them back under the stitching" so that the stitches pierce two layers of the cloth. That would help but the stuff isn't what I'd call real durable...frequent resheathing could screw it up over time.

What about a layer of chamois leather instead? Spray a silicon-based light oil into it once a month or so, it'd be almost as good as cloth, wouldn't hurt the blade any and would be tougher?

All of this would work FAR better on a single-edge blade. Double edge would shred the "lining" of whatever type a lot faster.

It might also be possible to link the inner and outer kydex plates with screws/bolts, so that it can be disassembled for easier replacement of the lining every few years? Use the fasteners that are hollow clean through and you've also got most of your lace-holes.

Jim March
 
Well, Jim, here's my idea, and you can do with it what you want. All I ask is that if it turns out to be the next big thing, please credit me with the idea, and allow me to use the design without legal repercussions!
wink.gif

If I was trying to do this, I would use a two-piece pancake style sheath that is held together with screws for full dissasembly potential. Then I would squirt a little 3M spray adhesive onto the insides of both pieces of Kydex and slap a piece of Velcro on each side. Actually, I'd put four pieces of Velcro inside. Heat the material and mold it to the knife, then do all the finish work, etc. Then I would take the Tuf Cloth and spray the adhesive on it, attaching two of the Velcro halves to the Tuf-Cloth, and then the Tuf-Cloth would be held in place mainly by the velcro, but also by the screws. So, in cross section, you would have:
Kydex layer
velcro
velcro mate
Tuf Cloth
knife
tuf cloth
velcro
velco mate
Kydex layer.
It would be a little bulky, but it could work, and the Tuf Cloth would be replaceable simply by replacing it with a new ppiece of velcro. make sense?

------------------
My Custom Kydex Sheath pagehttp://www.geocities.com/CollegePark/Lab/1298/knifehome.html
Palmer College of Chiropractic
On Two Wheels
 
:
I don't know anything about Kydex so take what I am going to ask with that in mind Okay?
smile.gif


I am wondering about sewing any kind of cloth that could atract moisture even a silicon impregnated one.I get the drift of sewing it on with the small holes though.

Jim do you think the small hoes might cause quite a bit of structue instability to the Kydex?
How far apart are you considering them?
If the Kydex is heavy and stiff enough why wouldn't a series of good sized holes down each side of the scabbard work.They would lighten and aerate the scabbard to where moisture could run/evaporate off?

I was asking Chiro once about using some square or rectangular brass
strips to reinforce the Kydex for stiffening and there was perhaps a difficulty in getting them to stay put.I am still wondering if they couldn't be formed in thier own channels or something though.

It may be possible to add some rigidity with some kydex strips added down the side and such?
Perhaps like an "I" beam construction?

I wish I knew something about the material.Is it kind of like a hard smooth plastic that can be formed by heat.I am assumeing since Chiro said something around 225* I think.

Now to give away a thought.Since the R & D outfits have figured out how to put anti-germ agents in plastic for use in childrens plastic toys and high chair trays and such.....Why couldn't some kind of moisture proofing and/or lube be put in the plastic too?
Hellfire I know I can't be the first to have thought of that.How do we know something like that hasn't been discovered yet?

------------------


>>>>---¥vsa---->®
The civilized man sleeps behind locked doors in the city while the naked savage sleeps (with a knife) in a open hut in the jungle.

 
Yvsa, I was considering fairly small holes spaced maybe 1/4" apart, perhaps a bit closer but not much more. I don't see a structural integrity issue, kydex is REAL tough stuff. It's not "ordinary plastic", it's a high-grade thermoplastic with very few uses, really...it's expensive as plastics go, we use it for sheaths only because it can be hand-formed using standard kitchen stuff, for any kind of high volume injection molding is the way to go and that's where the antibacterial bits are added.

It actually molds easier at about 350F but can be "stiff molded" at around 225F. In fact, boiling water or steam from a kettle spout can be used to selectively soften just one area of a mostly-finished sheath, to "fine tune" one area.

It also comes in various thicknesses. .060" is about the thinnest we use, .090" (or .093") is quite common, and .125" not unheard of. I personally think .125" would make a fine "baseplate" piece and .090/.093 would make a good "top piece". Scott Evans invented a strange "two-ply top piece" made of .060 over the whole thing, but then a second layer of .060 in selected areas to increase retention without it being "too stiff". See, the stuff has "springiness properties" almost on a par with a similar weight in spring steel, it's really cool. I think he could perhaps have compromised with a single sheet of .090/.093 versus the complex two-layer top and had similar results.

In other words, Scott did something like your "I-beam reinforcement" but you can get similar effects by picking the thickness in proportion to the "spring strength" you want.

Mad Dog uses .093 exclusively, but for solidity he uses a double-layer baseplate in most of his designs, especially those that are "jump qualified". Any sheath rated for parachute use is also strong enough for motorcycle crash survival, something I have to consider.

Speaking of which: we've got to make sure any tip-up carry can't drive the point up and through the sheath on a feet-first fall where the pommel catches on something solid. That means stainless steel rivets or other (screw?) fasteners, I think.

Jim March
 
Chiro, I know you're monitoring the thread...do us all a favor, ship Bill a little bit of any kydex you might have laying around? As little as 6" by 12" or even less...it'd be GREAT to get Kami Sherpa's reaction to the stuff! Heat it at 350F in an oven for 10 minutes, handle it with gloves, it rapidly turns rock-hard in whatever position it "freezes" in...and a single .125" thickness can stop just about any knife thrust dead in it's tracks.

He'll realize the implications *immediately*
biggrin.gif
.

Jim March
 
While you're still brainstorming, here are some ideas to help you explore other possibilities.

How about making a removable liner? Make a khukuri "sock" out of Tuf Cloth, insert a wooden (or other material) frame and insert that into the sheath. When you get soaked and are ready to dry out, insert a dry liner while the wet one dries.

Or, what about suspending the blade in the sheath? (I don't know much about Kydex either) Make the throat the primary contact point around the handle and 1/2" to 1" up the handle. Ventilate the sheath so any water that goes in evaporates or runs out and keep your blade well oiled.

Well, I didn't say they were great ideas, but that's what brainstorming is all about.

Richard

[This message has been edited by RHJohnson (edited 09 September 1999).]
 
Hmmmm...Richard, you're thinking but...well, I'll show you the problems as I see 'em:

1) Removable liner: not bad, but...frequent draws and re-sheaths in the field could get annoying, and if the liner isn't anchored well it could interfere with draws.

Plus, in the gun world a key concept is "one handed re-holstering if necessary". Because if you draw and/or use in defense, odds are someone similar to a cop will be along to sort things out...putting your weapon back into a non-threatening holstered position ASAP could be critical.

I see no reason NOT to apply this to huge combat blades.

2) "Suspending" the blade: Welll...the kydex needs be molded right to the blade shape while hot and limp. You could wrap the blade first with something and then layer the kydex, but the sheath's bulk would go up if you want minimal contact with the steel, and the blade wouldn't be held very tightly...that's not good. And you STILL get some contact where rust might form.

The "springy" properties of the kydex hold the blade and part of the grip all over, evenly. That's why you can break free of traditional "pull it out the hole in the top" thinking and switch to "break sideways" draws. But that means you need lots of kydex-to-blade contact...it can be on the other side of oiled cloth though.

In case you haven't seen it yet, this thread contains a complete description of The Outsider's sheath. While it's not a Khukuri, the sheathing requirements are strikingly similar.
http://www.bladeforums.com/ubb/Forum26/HTML/000306.html

Jim March

[This message has been edited by Jim March (edited 09 September 1999).]
 
I am amazed at the variety of ideas presented here. I am sure our sarkis would be overwhelmed.

Uncle Bill
 
A Tuf-Glide coat by itself will protect the blade from water without having a liner. I have gone for walks in the winter with my large AK and had the sheath filled up with sleet / hail / snow etc. for a couple of hours, and it did not rust. Just dump it all out when I get home and recoat the blade.

I recently took two pieces of iron, one with no protection and one just coated sloppily with Tuf-Glide (squeezed out and not wiped down), and left them outside periodically spraying them with water (every time I went out on the step, say 4-5 times a day). The uncoated iron rusted within a couple of hours showing pitting already. The coated strip resisted rusting for several days and took much longer to reach the level that the uncoated iron rusted in just the first couple of hours.

However if you are on a motorcycle then the water could impact with more force and possibly knock the coating off so as to induce rusting much faster. Therefore you might very well want a self-protecting blade. One thing to consider though is that for people using their knives what kind of a mess would it make if you sheathed the blade before cleaning it.


-Cliff

[This message has been edited by Cliff Stamp (edited 09 September 1999).]
 
Hello Jim, Uncle Bill, and all,

(For Oji-chan Bill -- Oi-chan here!)

Let me first say that I’m one of those folks who believes that the concern over corrosion in non-stainless carbons tends to be exaggerated. It happens, but not overnight, and it also doesn’t take active daily vigilance to minimize/prevent rust -- just occasional TLC. (Of course, I’ve lived most of my life in dry SoCal ... Still, the folks who are most “at risk” as precisely those who don’t know much/care about knives.)

That said, I think Yvsa’s initial idea is probably worth trying out, particularly given kydex or concealex’s strength:

“If the Kydex is heavy and stiff enough why wouldn't a series of good sized holes down each side of the scabbard work.
They would lighten and aerate the scabbard to where moisture could run/evaporate off?”

Kydex sheaths usually have drain holes at the bottom -- but would it also be possible to cut out holes, slots, grids, whatever, throughout the body of the sheath to allow its knife to breathe. Besides, moisture wicking *inside* kydex may well draw moisture from the blade, but it will still take quite a while to evaporate *out* of an enclosed sheath, no? Cutting out holes to aerate, as Yvsa has suggested, may sound tacky at first ... but then again, w/a little creativity, it may well offer new design possibilities, innovative patterns which don’t compromise strength, etc. Think of it as a creative challenge!

My 2 --
Glen
 
Jim,
First let me say that I generally lurk in this forum, this time the topic caught my eye as it is something I am familiar with.
To start, there is a paralell universe here at blade forums.... bore through these March "worm holes". http://www.bladeforums.com/ubb/Forum19/HTML/000152.html and http://www.bladeforums.com/ubb/Forum19/HTML/000166.html
(forgive me if I have just in some way connected some type of matter and anti-matter!)
I have seen, and worked with, some of the current Edge Works prototyping on Khukuri style blades. With all my ranting having been rendered as a qualifier..... Jim, are your moisture concerns
A)"in service" concerns... as in... I was out for the day and during my juant my blade become overwhelmed with rust because of this kydex. In this scenario I do not see how any sheath would not have certain disadvantages and maybe synthetics having and edge due to roll off vise other material having saturation problems.
B)"post service" concerns... as in.. I was out for the day, it rained, I wiped everything down thourghly, and in the morning my blade was rusty because of this kydex. In this scenario I can see some concern but possibly not as big of a problem as might first appear. The synthetics have a tendency to stay open and thus dry extremely fast. In post service from a high moisture environment, no matter what the building material, most users would remove thier blades from the scabbard anyway.
I want to give some more thought to this, and am very intrested, but do not fully understand all of the problem.
Another question... how does the steel in a Khukuri compare as far as its disposition to rust as to the steel in an exposed edge of a Ka-Bar fighting knife? The ka-bars tend to rust and yet they do seem to hold up real well, with minimum care, in kydex.
Also, with the discussion of sewing material to kydex you are talking about custom, one at a time, or home sheathing aren't you?

------------------
>)-RadarMan-(<
age:38
Three can keep a secret if two of them are dead.... Vermont Proverb
Click to expand...


[This message has been edited by RadarMan (edited 11 September 1999).]
 
Radarman: I know that post-wet-spell, the blade will have to be dried then left OUT of the Kydex sheath while it dries. My only concern is that on a long bike trip, the "wet spell" could last a while; I've ridden up to seven hours continuous in rain, I rode four hours that way with The Outsider and it's sheath on.

Worse, while I don't consider The Outsider a great wilderness survival knife, this new Chainpuri of mine most certainly IS. And I *do* go on longish solo camping trips once in a while, although not lately (sigh). Anyways, that's probably close to a "worst case scenario".

All that said, I've been reading up on the rust-resistance left by these thin-film silicon cloths. Quite impressive, to say the least...it's possible the whole subject is "overkill thinking" on my part.

As to Edgeworks: Scott Evans helped fine-tune that sheath design. He's a *great* craftsman, great guy. As I've told him in private EMail, I feel he's "part owner" of the design and has my blessing to develop it further or make variants for other people with no "royalties" to me. We both feel Khukuris are a top target.

I'll be very interested to see what he comes up with for Craig's customers, and again: he has my blessing to do so.

Feel free to link this thread into those discussions.

--------------

Glen/Storyville: Very interesting post! For starters, you're probably right that some of these measures may be overkill. Second, the "drainhole" concept is not only sound, it can perhaps be used to solve a second problem at the same time: the "tension issue".

Scott found that .125" Kydex for a top panel made the whole thing "way too stiff on the draw". His solution was two .060" sheets bonded together and the upper layer mostly cut away to reduce tension across key areas. But that's DAMN difficult to pull off for anyone lesser.

Well gee...you could get the same effect with holes? Swiss-cheese one area and it'll flex easier, you could fine-tune the tension that way. Cover the whole thing with a thin layer of some semi-absorbent cloth (Cordura?) and it would look great.

God I can't wait to score some Kydex, try some of this stuff out.

Jim March
 
Jim,
I also believe that the rust inhibiting products on the market today are the ticket for blade protection. As kydex is extremely resilient to chemicals, barring deet which is more like a hazardous waste, I think the best "liner" for kydex would be a silicon or teflon chemical alone. Applied to the blade and put in the sheath I think you are getting a good protection. As always there are trade offs... anytime you put anything in a kydex sheath except blade you increase the chances of contamination. Again, a chemical is better than a clothe lining because you can still rinse the sheath out, possibly with another chemical that would flush out the sheath completely for dry use. So basically we may be looking for a large "flush" hole or slot vise a "drain" hole. hmmmm...... I seem to be thinking out loud again.....

------------------
&gt;)-RadarMan-(&lt;
age:38
Three can keep a secret if two of them are dead.... Vermont Proverb
Click to expand...


 
Namaste!

Will someone send me a piece of this kydex so I can see what it is? And perhaps instruct me as to how it is used.

Thank you.

Pala
 
You must log in or register to reply here.
Back
Top