Have to kindly disagree @KLE. The point of failure varies greatly, and simple physics apply. I did a study on plastics for my Mech Engineering degree, and without getting too nerdy, heres a quick breakdown of a few material type and temps where they go into brittle states (Tg below).
If we knew the exact polymer compound KelTec used we could speculate a good usable range.
I would still contact Keltec because they likely have these material specs, which combined with shock of small explosions happening in close proximity to the polymer would have them advising us what the effective environmental limits should be. Primarily because they are warranting the product, but maybe they care a little about personal injury too
[quote=“Stircrayzy, post:4, topic:12457”]
point of failure varies greatly
Excellent chart and explanation.
Didn’t find that there are structural failures occurring at normal temperatures or temperatures outside the norm both hot and cold.
After searching the web I did find the type of plastic used by KalTec to fabricate most of the SUB2K.
The polymer of the weapon is made of an impact modified glass reinforced Zytel.
Not listed on your chart, but I found this link.
No temperature ranges mentioned but does say this;
The properties of Zytel will vary with the specific formulation. Formulation Zytel HTN 35% Glass Reinforced Resin, consisting of 35% glass fiber by weight, has a tensile strength of around 30kpsi and a flexural modulus of 1500kpsi under room temperature conditions. Zytel also offers good chemical resistance to common chemicals such as motor oil, transmission fluid, and methanol, and shows little thermal expansion. Other additives or treatments may be used to increase toughness, wear resistance, and temperature tolerance.
Out of apprx. 35 Dupont listed variations i could find of Zytel, the Tg brittleness (*i interpret that spec as our potential failure point) rating starts at -58C which means you should probably be good in most humanly tolerable conditions . Most of the Tg specs are in the neighborhood of -100C .
For the record, the melting points are in the 200-260C range, so dont feel bad about leaving your sub in the car out in the desert, where you wont even likely get to 90C.
***Standard disclaimer applies, im not liable for anyones use of my interpretations.
Bear in mind we’re talking about Kel-tec here. We’re also talking about the “pure” forms of Zytel. There have been catastrophic failures of the polymer used in KT firearms, especially due to the coloring process used. I wouldn’t rely on those temperatures being the actual failure points for KT - they cut corners and squeeze pennies until Old Abe himself hands John Wilkes Booth a bullet.
There is no pure zytel, its just a trade name for a family of similar nylon resin based products.
The numbers i stated were taken from the known, standard zytel polymers.
You are right to point out that additives create unknowns, and KT’s proprietary mixture cant “directly” be compared here, just generally discussed.
Excellent points… as always!
I was trying to sweep the facts under the carpet, LOL.
Now I am not that sure anymore.
It would be great to keep including the SUB2K in the monthly shoot Division “B” PCC 50 yards, but I think if it’s well below zero I will not take a chance.
Like the old saying goes “How much is your piece of mind worth”.