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anyone heard that after time a zytel handle may warp causing the blade to loosen due to hot cold changes??
thermoplastic-zytel warpage?
- Thread starter paulwesley
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Oh, Oh, I'm busted.
Zytel will not warp due to hot cold changes that you would find during any kind of standard use. The Zytel grades that are used for knife handles might tweak if you got them above 150F and subjected them to a substantial mechanical pressure (maybe a 10,000 PSI) for a short time or a somewhat lower pressure for a very long time (hundreds of hours). Below 150 F you can break it, but you cannot warp it.
Just as an example, Zytel is molded at ~500F and ~7500PSI. Takes a lot of heat to melt it and even then it takes a walloping lot of pressure to make it flow.
It is possible to have a part that comes out of the mold warped due to improper molding temps and pressures. But if it comes out good, it stays good.
The stuff is pretty bullet proof at the temperatures and pressures found when using knives.
Which is why I can't understand unlined Zytel closing up on the blade when EDC'd after 6 weeks, like my Gen 1 Endura. Or why it opened back up.
Zytel is made of nylon, and nylon does have cold flow character according to my reference, meaning when put under pressure over time, it will change shape. It has nothing to do with the convenience of large scale production temps and presssures. One of the unfavorable reasons it's not used as a bearing material, etc since its invention 50 years ago. It was noted as a disappointment at the time, as it was the specific intent. Glass reinforcing is the answer to the problem now and under normal use most knives don't seem to exhibit much of it - except mine.
Large framed knives seem to always have liners now that resist it - but IMHO it's always there.
Zytel is made of nylon, and nylon does have cold flow character according to my reference, meaning when put under pressure over time, it will change shape. It has nothing to do with the convenience of large scale production temps and presssures. One of the unfavorable reasons it's not used as a bearing material, etc since its invention 50 years ago. It was noted as a disappointment at the time, as it was the specific intent. Glass reinforcing is the answer to the problem now and under normal use most knives don't seem to exhibit much of it - except mine.
Large framed knives seem to always have liners now that resist it - but IMHO it's always there.