FRN Strength / Durability

[James Y]

I own an old Seki-made SOG Seal 2000 fixed blade knife from 20 years ago, and its handle is Zytel (FRN). The FRN used for it must have had a very high glass content, because its handle is VERY hard, heavy, and dense.

Jim

[Bill1170]

I own an old Seki-made SOG Seal 2000 fixed blade knife from 20 years ago, and its handle is Zytel (FRN). The FRN used for it must have had a very high glass content, because its handle is VERY hard, heavy, and dense.

Jim

I recall handling a Gerber LST that was similar to what you described. Very stiff and hard. What I like about Seki FRN is its softness, which is kind to the hand. And yet my linerless Pacific Salt isn’t all floppy in use. It’s about the balance of properties.

[The Deacon]

I suppose you're right. Just makes me curious as to what temperature it can survive exactly. Where the melting point of FRN sits at, might be surprising I feel like.

[James Y]

I own an old Seki-made SOG Seal 2000 fixed blade knife from 20 years ago, and its handle is Zytel (FRN). The FRN used for it must have had a very high glass content, because its handle is VERY hard, heavy, and dense.

Jim

I recall handling a Gerber LST that was similar to what you described. Very stiff and hard. What I like about Seki FRN is its softness, which is kind to the hand. And yet my linerless Pacific Salt isn’t all floppy in use. It’s about the balance of properties.

Yes I, too, really like Spyderco’s Seki/G. Sakai FRN. As you say, it has a perfect balance.

Jim

[DeadForests]

I suppose you're right. Just makes me curious as to what temperature it can survive exactly. Where the melting point of FRN sits at, might be surprising I feel like.

Mleting Point Of Nylon.png

If this is comparable to the melting point of FRN, then I think it is suitable. 500 degrees is pretty solid, as that is basically an oven at that point. My guess would be correct if this is true as well, as then FRN would only be susceptible to very high levels of heat like a open flame. If your knife is being subjected to an open flame levels of heat, I think you have other problems at that point.

[DeadForests]

FRN's cheapness is only a perception.

One day over 20 years ago, I was on a paved walking trail at the beach, and some guy asked if I had a knife, and could I help him. I suppose he saw the pocket clip of the Delica 3 in my pocket. I'm not 100% on what it was he wanted cut, but best I can recall, it was a zip tie or some type of plastic strap on his daughter's roller skate. I pulled out my D3 and he said, "You sure that plastic knife can handle it?" Almost before he could finish his sentence, I severed the zip tie, or strap, or whatever it was, and he said, "Oh..."



Jim

I honestly wonder if we didn't use so much disposable plastics, if we would still find plastics to be cheap in concept. If plastics were only used for applications that would see use, rather than things like plastic wrapping for a box, I wonder if we would view plastics for what they really are.

[James Y]

FRN's cheapness is only a perception.

One day over 20 years ago, I was on a paved walking trail at the beach, and some guy asked if I had a knife, and could I help him. I suppose he saw the pocket clip of the Delica 3 in my pocket. I'm not 100% on what it was he wanted cut, but best I can recall, it was a zip tie or some type of plastic strap on his daughter's roller skate. I pulled out my D3 and he said, "You sure that plastic knife can handle it?" Almost before he could finish his sentence, I severed the zip tie, or strap, or whatever it was, and he said, "Oh..."



Jim

I honestly wonder if we didn't use so much disposable plastics, if we would still find plastics to be cheap in concept. If plastics were only used for applications that would see use, rather than things like plastic wrapping for a box, I wonder if we would view plastics for what they really are.

I think that plastic is often associated with cheaply-made products like kids' toys, plastic tableware, red solo cups, straws, and other disposables. People in general don't realize there are different categories of plastics. And that something like FRN, which most people wouldn't even know what that is, is in a totally different category of plastics.

Jim

[The Deacon]

If this is comparable to the melting point of FRN, then I think it is suitable. 500 degrees is pretty solid, as that is basically an oven at that point. My guess would be correct if this is true as well, as then FRN would only be susceptible to very high levels of heat like a open flame. If your knife is being subjected to an open flame levels of heat, I think you have other problems at that point.

While I'm sure it would take a much higher temperature to melt the glass fiber flock component of the FRN, I doubt it would have a significant impact on the melting point of the nylon. Kinda like melting chocolate chip ice cream. But yes, there would be other problems at that point. Heck, you'd have other problems long before that point. That doesn't change the fact that, compared with most other "something embedded in a polymer" composite materials commonly used for knife handles, FRN is either the least heat resistant, or among the least heat resistant. Still, it's likely that the only "real world" scenarios where this matters is if you want to drill or sand your knife's handle. Power tools and FRN do not play well together.

[Bill1170]

Some make a distinction between plastics and “engineering plastics” in an effort to distinguish between cheap disposables such as Solo cups and durable goods such as Delica handle slabs. Another distinction to be made is between “just plastic” and fibered composites like FRN where nylon (a plastic resin) is the matrix and glass fibers are the tensile reinforcement that give it such strength. Of course, both G10 and carbon fiber composite are also fiber-reinforced plastics, but they both use long fibers (often cloth) and thermoset resins like epoxy, so they can’t be injection molded like FRN, which uses a thermoplastic (nylon) and short-fiber reinforcement.

[DeadForests]

Some make a distinction between plastics and “engineering plastics” in an effort to distinguish between cheap disposables such as Solo cups and durable goods such as Delica handle slabs. Another distinction to be made is between “just plastic” and fibered composites like FRN where nylon (a plastic resin) is the matrix and glass fibers are the tensile reinforcement that give it such strength. Of course, both G10 and carbon fiber composite are also fiber-reinforced plastics, but they both use long fibers (often cloth) and thermoset resins like epoxy, so they can’t be injection molded like FRN, which uses a thermoplastic (nylon) and short-fiber reinforcement.

Do you think you could give me a quick rundown on engineering plastics? I think it has to do with plastics that are designed for certain applications, but I might be wrong.

[DeadForests]

FRN's cheapness is only a perception.

One day over 20 years ago, I was on a paved walking trail at the beach, and some guy asked if I had a knife, and could I help him. I suppose he saw the pocket clip of the Delica 3 in my pocket. I'm not 100% on what it was he wanted cut, but best I can recall, it was a zip tie or some type of plastic strap on his daughter's roller skate. I pulled out my D3 and he said, "You sure that plastic knife can handle it?" Almost before he could finish his sentence, I severed the zip tie, or strap, or whatever it was, and he said, "Oh..."



Jim

I honestly wonder if we didn't use so much disposable plastics, if we would still find plastics to be cheap in concept. If plastics were only used for applications that would see use, rather than things like plastic wrapping for a box, I wonder if we would view plastics for what they really are.

I think that plastic is often associated with cheaply-made products like kids' toys, plastic tableware, red solo cups, straws, and other disposables. People in general don't realize there are different categories of plastics. And that something like FRN, which most people wouldn't even know what that is, is in a totally different category of plastics.

Jim

But don't forget about Legos. Those bricks are strong! Also painful.

[James Y]

FRN's cheapness is only a perception.

One day over 20 years ago, I was on a paved walking trail at the beach, and some guy asked if I had a knife, and could I help him. I suppose he saw the pocket clip of the Delica 3 in my pocket. I'm not 100% on what it was he wanted cut, but best I can recall, it was a zip tie or some type of plastic strap on his daughter's roller skate. I pulled out my D3 and he said, "You sure that plastic knife can handle it?" Almost before he could finish his sentence, I severed the zip tie, or strap, or whatever it was, and he said, "Oh..."



Jim

I honestly wonder if we didn't use so much disposable plastics, if we would still find plastics to be cheap in concept. If plastics were only used for applications that would see use, rather than things like plastic wrapping for a box, I wonder if we would view plastics for what they really are.

I think that plastic is often associated with cheaply-made products like kids' toys, plastic tableware, red solo cups, straws, and other disposables. People in general don't realize there are different categories of plastics. And that something like FRN, which most people wouldn't even know what that is, is in a totally different category of plastics.

Jim

But don't forget about Legos. Those bricks are strong! Also painful.

So true. Ouch!



Jim

[James Y]

Some make a distinction between plastics and “engineering plastics” in an effort to distinguish between cheap disposables such as Solo cups and durable goods such as Delica handle slabs. Another distinction to be made is between “just plastic” and fibered composites like FRN where nylon (a plastic resin) is the matrix and glass fibers are the tensile reinforcement that give it such strength. Of course, both G10 and carbon fiber composite are also fiber-reinforced plastics, but they both use long fibers (often cloth) and thermoset resins like epoxy, so they can’t be injection molded like FRN, which uses a thermoplastic (nylon) and short-fiber reinforcement.

Thank you for sharing.

Jim

[Bill1170]

Some make a distinction between plastics and “engineering plastics” in an effort to distinguish between cheap disposables such as Solo cups and durable goods such as Delica handle slabs. Another distinction to be made is between “just plastic” and fibered composites like FRN where nylon (a plastic resin) is the matrix and glass fibers are the tensile reinforcement that give it such strength. Of course, both G10 and carbon fiber composite are also fiber-reinforced plastics, but they both use long fibers (often cloth) and thermoset resins like epoxy, so they can’t be injection molded like FRN, which uses a thermoplastic (nylon) and short-fiber reinforcement.

Do you think you could give me a quick rundown on engineering plastics? I think it has to do with plastics that are designed for certain applications, but I might be wrong.

There are so many plastics that fall under that label. Some are optimized for strength, others for machinability, others for high melting point, and so on.

There’s a lot of current interest in high temperature thermoplastics that can be heated to liquid and infused to saturate a fiber preform and thereby create a strong composite part much faster than possible with a thermoset. Cooling a hot melt to freeze it solid is much faster than waiting for a chemical reaction to cross link small molecules into long chains.

Another benefit to thermoplastics is ease of recycling. So-called “plastic lumber” is often fibers of recycled cellulose (from plant matter originally) encased in a thermoplastic matrix derived in whole or part from recycled plastic products taken out of the waste stream.