Kydex vs. Zytel vs. Leather Sheaths in Freezing Temps

C

CraigR

Joined
Dec 23, 2003
Messages
42
Ok, I recently ordered a Kydex sheath to go with my F1 knife. After taking it out on multi-day hikes I started noticing a problem. The friction fit was starting to collect a lot of dirt. Finally, after working on some wood with a lot of pine resin, the knife actually got stuck in the sheath and was hard to remove. Since I live in an area where we get very wet snow during the day and freezing temps at night I thought that in winter conditions this kind of Kydex sheath would be a problem as the knife could freeze inside. So I tested it in my freezer and sure enough it did bind up.

Well I decided to take this a step further and have a collection of my knife sheaths from Kydex, Zytel and Leather exposed to the same tests. What I found is that the Kydex sheaths were poor to marginal performers when put into freezing temps. Leather was second best. Zytel, as used with the Fallkniven brand knives, was the best. I made a video of my tests here:

http://www.youtube.com/watch?v=6LhBfUbPtfs

This video not only has my results from controlled testing, but also I have a response from Peter Hjortberger of Fallkniven about why they use Zytel in their knife sheaths and moved away from Kydex some years ago. I think people interested in knives will find his response enlightening. I hope you enjoy this video, I enjoyed making it and learned a few things about knife sheath design for cold weather myself.
 
Good to know. Thanks.
 
I commented on youtube earlier, but just wanted to say again that I think this video was a great idea and very well done.
 
That's a unique question answering review. Mostly it make me happy I live in a milder climate. How os the VG10 holding up to all the moisture?
 
Deviltooth said:
That's a unique question answering review. Mostly it make me happy I live in a milder climate. How os the VG10 holding up to all the moisture?
Click to expand...

VG10 works great. No problems. CPM154 is also working great in other knives. 3G I've been testing and it is getting microchips on the edge and I don't recommend it. Carbon steel is OK, but you need to be really careful and mostly it's so wet at times that it's going to rust no matter what you do.
 
Good test Craig.

Ive got a custom kydex sheath for my F1 and a SpecOps Combat Master for my A1. The Combat Master is a cordura sheath with a kydex insert, and after seeing your vid, i think im going to boil the insert and remould it to be looser fitting.

Ive still got the original Zytel sheaths for my Fallkies.

Thanks for posting :thumbup:
 
Great review, very clear and succinct. Thanks for the enlightening information, even though I've yet to camp in snow or freezing temps- it's something to consider. As I usually have my F1 (with a leather sheath) in wet conditions, I'll be looking out for their Zytel sheaths on my next Fallkniven purchase; an A1.

Look forward to looking up the rest of your reviews. Please keep it going.

Best,
-di
 
Great review !
Quick question: If someone had a custom kydex sheath that held the blade a little too snugly once the handle was popped lose, could you put some duct tape on blade-insert the sheath in hot water-& resheath the knife w/duct tape (for greater thickness) to eliminate the wet/freezing sticking knife issue ???
 
Many thanks for something that's very relevant here in the Rockies! -50 F ambient happens on occasion, and I believe most folks know all too well "Murphy Never Sleeps."
 
TwinStick said:
Great review !
Quick question: If someone had a custom kydex sheath that held the blade a little too snugly once the handle was popped lose, could you put some duct tape on blade-insert the sheath in hot water-& resheath the knife w/duct tape (for greater thickness) to eliminate the wet/freezing sticking knife issue ???
Click to expand...

I don't know. Some of the other kydex sheaths were still pretty loose but still held water enough that it could be a problem. You don't want anywhere for the water to collect. It must drain well and the Fallkinven sheaths were very good about letting the water out. Others weren't as good. Also I'm concerned the Kydex will be brittle at cold temps. The Kydex sheaths felt like they could crack if they were just a little colder. The Zytel felt still flexible and the leather felt kind of in between.
 
Great work Craig.

Kydex definitely gets more brittle in cold. In hard impacts it can crack or the construction itself (rivets and other hardware) can break. It has in the past.

Nylon hardware also get brittle in cold temps. The high performance version, Delrin does somewhat better.

As for leather, it is and has been a reliable material choice for an awful long time in northern/arctic countries for a huge range of applications.

But this really underlines the importance of design and construction considerations. In professional applications work functions and conditions can cause the item to damage, fall out of a holster or a pouch or a sheath fill it with debris. It should be obvious that application, Water, sand and other debrii are all things that should be considered by the maker. It is my guess that the amateur kydex benders don't much...
 
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Yes you are right that the sheath design is very critical. Peter at Fallkniven put importance on the sheath design because he correctly stated that the sheath design affects the knife availability. After having my knife get literally glued into my tight fitting Kydex due to some small amount of pine sap on the blade it made me realize that the friction fits are not that great of an idea. The sheath was already starting to collect lots of dirt that was making the blade tough to insert and remove, but the sap was the final straw. So even if you are not in a freezing environment, there are still other environmental considerations.
 
Great video and insight, thanks!!

While on subject, are there any businesses out there that offer services to make custom zytel or SpecOps sheaths for blades like the services to make custom kydex sheaths?
 
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