Polymer Plastic (Nitrolon) flashlights vs. Aluminum

moerush04

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I scoured the CPF database and could not come up with much that talks about this topic. Why are most flashlights these days still mostly made of metal instead of plastic like some of the Surefire lights? I want to get your opinions on this topic. Modern handguns and assault rifles are made of as many plastic polymer parts as they can. At first the gun advocates shunned the 'tupperware' guns. But history has proven, polymer has become the 'standard' of which most guns are made of now. Why not flashlights too? Here is my take.

I think the integration of polymer or Nitrolon (I guess they call it) into the Surefire G2X type lights are close to what what the future flashlights will look like. The tailcap, and battery tube are made of polymer plastic, the head may still be made of aluminum to dissipate heat, and the bezel is also made of polymer.

1. Polymer does not scratch as easily as aluminum. The type of aluminum all of my lights are made of has no malleability at all, the smallest force that causes it to deform is permanent. Polymers 'bounce back'. A light that has plastic will absorb much more shock than a light made of aluminum. And that's not to say that there would not be aftermarket stainless steel bezels, tailcaps, whatever. Or if the light comes with metal parts that you could get plastic aftermarket parts.

2. When a polymer is scratched, it does not expose the natural color of the material because the surface color of the polymer is its natural color. So no worrying about scratching off the finish or paint. Aluminum, even with the type III hard anodizing still scratches. Every one of my metal lights has a ding exposing the bare aluminum. It is hard to avoid, unless it spends most of its time on the display shelf. For those of us who use our lights every day, it is hard to avoid. All the dings and scratches give the light a beat up look, or a nice patina depending on how you look at it. Either way it does not look factory new after a few months of use.

3. Polymer lights are much lighter than aluminum lights.
4. I am speculating, but I am guessing that manufacturing plastic light parts has to be cheaper than turning an aluminum part on a lathe or machine.
5. Battery rattle in a plastic light will not be nearly as noticeable as in a metal one.
6. Do threaded plastic parts need O-rings to be water tight? This one I do not know but am trying to stir up more support for my theory.

Again, I know the idea or plastic polymer lights might seem like blasphemy to a lot of people who simply cannot imagine a 'tupperware' flashlight. It is just some food for thought/discussion. I personally like the metal light for reasons that echo some of the same reasons gun owners might prefer metal over polymer. I like the feeling of the metal in my hand. It feels solid. A lot more craftsmanship goes into making metal parts.

Does polymer plastic dissipate heat as well as metal? Do you think if an all polymer light was made (besides the electronics for all you jokesters), would the head still need to be made of metal for heat dissipation? I Think because of that and because polymer is malleable it will deform under pressure and might not protect the circuitry as well as aluminum, it would be best for the head to be metal.

As you can see, I have been pondering this topic for a while and look forward your thoughts on this matter. Thanks in advance.
Dan

Edit: My apologies, this thread might be more appropriate in the 'general flashlight' forum. Moderators please do not penalize me for this mistake, I did not realize it until after I opened the thread.
 
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BBL

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I agree. From a rational point of view, polymer should be the first choice for any normal-sized flashlight. And i dont understand why they carry plastic rifles with attached aluminium surefires. Probably too much money to spend...
When it comes to civilian buyers, theres often the 'toy aspect' - an aluminium flashlight is just more appealing than a plastic one.
 

Lynx_Arc

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Two big reasons polymer lights are less popular
1)They don't conduct heat away from the LED emitter well at all which makes for lights that cannot match high output LED lights.
2)It is easier to mill aluminum into a tube than it is to set up custom molds for plastic lights so the setup and development cost of metal lights is a lot cheaper with a lot quicker time to market.
I light polymer based lights myself but LEDs need to get more efficient to let plastic shine brighter.
 

kramer5150

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Plastics are thermal insulators, so they can't be used effectively in high current LED designs.
Many plastics can melt under extreme temperatures. So they are not the best choice for high output incans. Plastic mold tooling is more costly to tool up, versus milling, spinning and cutting Aluminum.

Lower current / cool running lights however can/do use plastics very effectively.

2 of my fave lights are a SF-G2 incan and LD25, both make use of thermo-formed plastics. They are GREAT cold/wet winter lights, when Aluminum chills the hands. Neither however are required to withstand high temperatures, or sink a lot of heat away from the LED....
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Both lights are water submersible (G2 O-ring gaskets pictured)
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dsc03530r.jpg
 
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geckoblink

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Like Lynx_Arc said, heat dissipation is the big issue. For my own part, I really love my all Nitrolon G2 with Malkoff M61LL. That dropin doesn't even heat up the Nitrolon head at all even after it runs 10+ hours straight.

Nitrolon + 100-ish lumens + long runtime = win.
 

peterharvey73

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I agree, plastic is a very good material with excellent value for money, hence it is used in entry level lights esp those sold in supermarkets.

However, when it comes to high quality flashlights at premium prices, aluminium is used - it looks and feels more upmarket in the hands, and it helps in heat dissipation, but it is not lighter, nor more scratch resistant, nor more durable, nor cheaper to manufacture.

Really really premium flashlights use titanium - looks great, but practicality wise, it is actually too heavy, the fully polished titanium surface is very slippery in the hand, and poor heat dissipation too...
 

tam17

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This was a hot topic some 30(ish) years ago in a small arms community, after a relatively unknown European manufacturer decided to introduce large reinforced polymer components into a handgun design.

Opponents of plastic materials were bragging about mechanical and thermal stress, unpredictable long-term fatigue properties, resistance to cleaners/lubricants and other chemicals, w/e.

Nevertheless, plastics proved to be up to the task, and Glock designers are today praised as visionaries and trend-setters. Just my EUR 0.02

Cheers,

Tam
 

StandardBattery

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The main reasons have already been stated. As LEDs become more efficient (less heat) though look for flashlights used in demanding applications to use more Polymers. Streemlight is also making several polymer based lights and have been for quite a while. Most people for EDC though don't need the top in performance so for smaller EDC lights the average person is not dependant on the performance characteristics of the build material and eastetics will probably always win out.

For my car light I was using G2, that had a failure (it was the drop-in), so I had switched back to MD2, TK-11 and Jetbeam III-M; now I'm back to the polymer G2Z in OD and I like it. I really light the polymer lights for applications where there is a good chance it could get dropped, kicked, smucked or where weather extremes can be expected. Luckily that's not the case with my EDC light where the weight of stainless steel is less of an issue to get the robustness I need in my keychain light.

Once it's easy to address the heat and electrical characteristics needed, and the manufacturing volume warrants it, I'm sure we'll see some good, and nice lookin', polymer designs.
 

Pandorum

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I once was a big fan of polymers but lately not so much anymore.
I believe they are inherently less stable over time than their metal counterparts, aluminum and stainless steel.
 

gcbryan

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Yes, o-rings are still needed. As a matter of fact I think aluminum threaded lights with a proper o-ring are easier to waterproof. I'm not a machinist but I am a diver and I've found small aluminum lights seem easier to mod for diving than small plastic ones. I think (with the right light) threads can be made finer in aluminum than in plastic.

That may not be fact but it is my experience. Both make good dive lights however.

I'd prefer a plastic (Delrin type) light for its lighter weight. To dissipate head I think in general you need an aluminum head and with higher powered designs you might need a hybrid such as metal strips running down the sides to a metal tail cap or some way to transfer the head.

Underwater Kinetics makes recreational dive lights and they have a fairly high powered one where they use the recoil design and mount the emitter and head sink through the front lens. At that point water does the cooling of course but you have to move the heat to the outside of the body for that to be able to happen.

I think with volume it's probably cheaper to mold plastic than machine aluminum but for smaller numbers it's probably the reverse.

With outdoor headlamps (hiking/camping) plastic is common even on reasonably expensive lights You don't have to worry about corrosion with plastic. You have more options with different shapes and lighter weight of course.

I'm sure more lights will be made from plastic in the future.
 
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duro

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As far as heat dissipation goes, polymer lights could have an aluminum insert? Just like with polymer handguns, steel inserts are used (mainly for the contact between the slide and the frame.)

So, polymer lights could very well be used with higher leds provided there is an aluminum insert. So I guess it would have to come down to more design implementations, and retooling.
 

duro

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Oh, in case you're wondering. Steel inserts have nothing to do with heat dissipation, but friction rather. Although for hand guards for polymer rifles, there are aluminum, or steel inserts that protect the users hand from heat, and of course the polymer melting from the heat of the barrel. So yeah. It could be done for flashlights. Main reason again, seems like cost to manufacture.
 

Th232

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The problem with a metal insert of some kind is that you've still got to get the heat from inside the light to the outside and then to the surrounding air. If I'm reading you right (I know nothing about polymer handguns) there'll still be a layer of polymer over the metal, so you'll still have a good amount of heat building up inside it.
 
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afdk

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:huh:I have wrote about this about one year ago. The first lights I bought were Underwater Kinitics polymer and have proven to be very reliable. Their LED lights are not as bright, but meet all safety requirments. I still keep one of the lights in my car loaded with AA lithium primary cells. It's 45 lumen output is fine for most car situations and runs a long time.
 
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GaAslamp

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Modern handguns and assault rifles are made of as many plastic polymer parts as they can.

The frames and stocks of firearms (and occasionally some other external parts such as triggers) are made out of plastic to save on weight and cost, as well as improve their environmental resilience, but there are trade-offs in many cases. For example, plastic-framed semiautos, due to their lower inertia, are generally more prone to "limp-wristing," which can induce malfunctions when used by those who are relatively inexperienced (or have weak hands, wrists, and arms); recoil is typically harsher as well.

At first the gun advocates shunned the 'tupperware' guns. But history has proven, polymer has become the 'standard' of which most guns are made of now. Why not flashlights too?

Many still do shun them because let's face it, plastic looks and feels cheesy and cheap--that's why they're still disparagingly called "combat tupperware." They're *A* standard that many people--law enforcement officers, private citizens, and some military alike--use for utilitarian purposes, but they're certainly not *THE* standard when it comes to judging the quality of firearms, particularly with regard to handguns. In fact, some of the factors that led to the popularity of plastic handguns, such as their reputation for reliability, have nothing to do with the plastic--like so many other things, the market was largely shaped by timing and happenstance (and the lower cost of molded plastic).

Don't get me wrong, my primary self-defense sidearm happens to be a plastic-framed pistol (M&P40) because it's extremely reliable and practical, but the plastic is still awfully cheesy--it's an ugly tool for an ugly purpose, but it gets the job done and the price was right. If I had paid a premium for it, then I'd expect something nicer, and some people feel the same about flashlights (as I'm sure you're aware--I'm just pointing it out for my argument).

I think the integration of polymer or Nitrolon (I guess they call it)

Polymer is a rather broad term, but for the purposes of this discussion it's a euphemism for plastic. Nitrolon specifically appears to be a glass-plastic composite, which in the common vernacular is fiberglass. All we really need to be concerned about is that it's a particularly tough plastic that is tailored for its purpose.

into the Surefire G2X type lights are close to what what the future flashlights will look like. The tailcap, and battery tube are made of polymer plastic, the head may still be made of aluminum to dissipate heat, and the bezel is also made of polymer.

It would be better to have the whole flashlight's body (and ultimately the user's body) act as a heat sink in order to dissipate heat far more rapidly. Plastics are superior for handguns in this respect since they help keep heat away from one's hands, but they are generally inferior for today's high-powered LED-based flashlights, since LEDs are so fragile when it comes to heat.

1. Polymer does not scratch as easily as aluminum. The type of aluminum all of my lights are made of has no malleability at all, the smallest force that causes it to deform is permanent. Polymers 'bounce back'. A light that has plastic will absorb much more shock than a light made of aluminum. And that's not to say that there would not be aftermarket stainless steel bezels, tailcaps, whatever. Or if the light comes with metal parts that you could get plastic aftermarket parts.

There are advantages and disadvantages to every material that could be used, and I think that having a choice, based on the individual's intended purpose and personal taste if that's a factor, is a good thing.

2. When a polymer is scratched, it does not expose the natural color of the material because the surface color of the polymer is its natural color.

And some of those who worry about appearance may think that plastic is naturally ugly, scratched or otherwise. :)

So no worrying about scratching off the finish or paint. Aluminum, even with the type III hard anodizing still scratches. Every one of my metal lights has a ding exposing the bare aluminum. It is hard to avoid, unless it spends most of its time on the display shelf. For those of us who use our lights every day, it is hard to avoid. All the dings and scratches give the light a beat up look, or a nice patina depending on how you look at it. Either way it does not look factory new after a few months of use.

Yep, some people actually like the appearance of wear from real-world use, sort of like the holster wear that some gun owners constantly fret about while others appreciate.

That aside, I have plastic flashlights that look like crap because of hard use (they haven't changed in color, but the wear is still quite visible), and an old stainless steel flashlight that still looks great despite hard use. In analogy, some people prefer bare stainless steel guns, as well, because they don't show wear nearly as much as other materials and finishes. If the looks of tools that are actually used is important, then I think that bare stainless steel is the way to go (although you'll be paying a cost and weight penalty for it).

3. Polymer lights are much lighter than aluminum lights.

So they're easier to carry but less formidable as improvised weapons. :)

Again, I know the idea or plastic polymer lights might seem like blasphemy to a lot of people who simply cannot imagine a 'tupperware' flashlight. It is just some food for thought/discussion.

I get it, and you have made some valid points about the advantages of plastics, but as you yourself hinted at, every design and material has its good and bad points. I certainly think people should give plastic flashlights a chance, depending on what purposes they have in mind.
 

AaronG

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I personally have no ill feelings towards quality polymers. To most of the population plastic = cheap and poor quality. The biggest downfall that's already been mentioned though is poor heat transfer. All aluminium lights actually get warm right to the tail, so the whole body is a heatsink. Also most metal lights use the body as part of the circuit which allows for a secure connection and the smallest possible size.

The pluses of polymer are that it's more comfortable to hold in cold conditions and it doesn't cause damage to other things it bangs and scratches against.
 

kramer5150

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As far as heat dissipation goes, polymer lights could have an aluminum insert? Just like with polymer handguns, steel inserts are used (mainly for the contact between the slide and the frame.)

So, polymer lights could very well be used with higher leds provided there is an aluminum insert. So I guess it would have to come down to more design implementations, and retooling.

Physically yes this works, as in the LD25 I pictured above. Its an aluminum light with a rubber/plastic grip molded around it. It works on the LD25 because it does not drive the XPG hard enough to generate that much heat.

So in a high heat design, thermally no... this won't work. Plastics historically have always been thermal insulators (materials of high thermal resistance, that do not conduct heat). I am not aware of any plastics that have a low enough thermal resistance to be used as heatsink material.

Heatsinks work on principles of conduction and convective radiation... Aluminum serves as an optimal material for both elements. First the heat must be conducted away from the LED, the heat needs a low thermal resistance path to "move" heat away from the heat source (LED). Heat always travels from a hot body to a cold body. This is why heatsinks are always designed to be cooler than the object they are drawing heat from.

So once the heat is conducted away from the source (via the low resistance path), it now needs to be convectively radiated outwards to the surrounding air, otherwise you just have a heat trap... a constantly warming object. The most effective way to accomplish this is to directly radiate the heat off the Aluminum to the surrounding/adjacent air. Heat once again travels from the hot object to the cold object. In convection the hot object is the heatsink and the cold object is the surrounding air, so heat naturally exits the warm body.

So if you encapsulate the heatsink in a plastic thermal insulator, you are preventing convective radiation to the surrounding air, and trapping heat.
 
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GaAslamp

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This was a hot topic some 30(ish) years ago in a small arms community, after a relatively unknown European manufacturer decided to introduce large reinforced polymer components into a handgun design.

Actually, Heckler & Koch, a well-known arms manufacturer, came up with the concept of a plastic-framed pistol, the VP70:

http://en.wikipedia.org/wiki/Heckler_%26_Koch_VP70

It didn't succeed for various reasons, including marketing and other aspects of its design, but it was the first plastic-framed pistol by about 12 years.

Opponents of plastic materials were bragging about mechanical and thermal stress, unpredictable long-term fatigue properties, resistance to cleaners/lubricants and other chemicals, w/e.

As well they should have, since many things made of plastic, then and even still now, exhibited poor stability, particularly over time. One of my other hobbies is collecting fountain pens, most of which are made from various forms of plastic, and I can tell you from firsthand experience that their material stability is highly variable. For example, the legendary Parker "51" was made of an acrylic that seems virtually eternal, while its successor, the 61, was made of a cheaper polystyrene that usually shrank and cracked after 10-20 years, making it difficult to find intact specimens. Lest we think poorly of lowly polystyrene, however, I have several vintage Sheaffer fountain pens that are made of polystyrene, and they all look brand-new--no shrinking, cracking, or fading on any of them. Additionally, I've seen acrylic parts on other items degrade over time, so it's not just the type of material, but how it's made.

Nevertheless, plastics proved to be up to the task, and Glock designers are today praised as visionaries and trend-setters. Just my EUR 0.02

Plastic per se was hardly the selling point, though. Glock proved over time that it could be done practically, but the real selling points were low cost (partly due to the plastic frame and partly due to its simple design), relatively light weight (also due to the plastic), low cost, the simplicity and safety of its trigger system (although many still strongly contest this point), low cost, reliability (nothing to do with the plastic), low cost, high ammunition capacity (again, nothing to do with the plastic), and low cost. ;) Once they took over the market with low cost, ease of use, and high reliability--a compelling combination--obviously this paved the way for others to follow, but it's not because plastic is better, just cheaper.

I once was a big fan of polymers but lately not so much anymore.
I believe they are inherently less stable over time than their metal counterparts, aluminum and stainless steel.

As I explained above, it depends on the plastic and how it is made. We can say at this point that experience in the firearms community has shown that plastic pistol frames CAN be stable over long periods of time, and in fact CAN have superior durability than aluminum. The problem is that plastics appear to be significantly easier to screw up than metals (although the latter can certainly be poorly made as well), so I don't blame you for being apprehensive. I guess I'm just asking people to keep an open mind to both the potential and problems of plastics. Obviously if you've had bad experiences, then that's going to weigh heavily on your decision-making process, and I wouldn't blame you there, either.

As far as heat dissipation goes, polymer lights could have an aluminum insert?

Yes, it could have a metal heat sink, but after a while that's going to get hot, too, and the heat has to go somewhere. Exposing the heat sink to the air (with as much surface area as possible) would be a good start (but then the flashlight wouldn't be all-plastic on the outside), and coupling it to a metal body would be ideal because the whole flashlight could then be a larger heat sink with a larger surface area that transfers heat to both the air and your body, which is basically another even bigger heat sink. Unfortunately, plastic blocks this valuable process rather effectively, limiting how brightly you can run a lamp and for how long--unless, that is, you install a truly massive internal metal heat sink, but that would obviously compromise the weight and balance of the flashlight.

Just like with polymer handguns, steel inserts are used (mainly for the contact between the slide and the frame.)

That's so the steel slide doesn't chew up the plastic frame, which has nothing to do with flashlights beyond the broad topic of using various materials, and the limitation of that regarding flashlights is described above.

So, polymer lights could very well be used with higher leds provided there is an aluminum insert. So I guess it would have to come down to more design implementations, and retooling.

It's at least partly about how and where to transfer the heat, and plastic, being a thermal insulator, always gets in the way. This is not a problem for firearms (it could even be an advantage in some cases), but it is for flashlights.

Oh, in case you're wondering. Steel inserts have nothing to do with heat dissipation, but friction rather. Although for hand guards for polymer rifles, there are aluminum, or steel inserts that protect the users hand from heat, and of course the polymer melting from the heat of the barrel. So yeah. It could be done for flashlights. Main reason again, seems like cost to manufacture.

If you're talking about lamps that get so hot that you have to protect the user from the heat, then yes, that could be done as you describe, and the resulting flashlight would probably somewhat resemble a rifle with a heat shield in some ways as well. ;) For the usual hand-held LED flashlight, however, it is better in terms of heat management to use a metal body for the reasons given above.
 
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Bullzeyebill

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I scoured the CPF database and could not come up with much that talks about this topic.

Try goodle, cpf only, at the top of every CPF page for searching. Entering "plastic vs aluminum" will bring up several posts re this topic. Also, see the Similar Threads found at the bottom of this page.

Bill
 
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