Ensuring ANSI FL-1 STANDARD impact shock drop resistance

Flashlight Modding and DIY Parts
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*FOI* the other day i bought 1m of so-called heat shrink tubing (or: heat shrinkable wrap) from ebay seller goldpart, 2.99$ shipped.


Since 1xAAA lights are small or slippery, I was inspired by cpf posts where some user was protecting his lights by such shrinkable wrap. I immediately liked his idea. The rubber ring/band/wrap/stripe on both ends of the flashlight serve multiple purposes:

  1. mainly, to absorb the shock force and dampen its stress peaks
  2. to protect the aluminum edges and anodization against scratches
  3. to provide better grip when the knurling is insufficient
  4. and to provide a more comfortable tooth grip when holding the tail area between your incisor teeth

Note: Commercial heat shrink tubing isnt available in all kinds of diameters. For a 14.0mm bezel diameter the next bigger tubing diameter is 16mmØ; 15.0mm or 14.0mm diameter heat shrink tubing does not exist! Of course you could also use 19.0mmØ tubing but this would result in thicker tubing walls because the wrap has to shrink from 19mm all the way down to 14mm. Personally, i am thinking that the chosen 16mmØ is just perfect for 14mm bezel diameters!

When you drop your light, the tubing should do a good protective job and the glass lens shouldnt break within the ANSI FL-1 STANDARD impact resistance indication! By the way, the trick to use rubber rings as shock absorbers was known to me from my other electronic gadget: the rugged aluminum USB sticks by Corsair!!

here the naked gadgets:

Luckily the Corsair rubber rings fit quite well on the Quark (my very preferred 1xAA EDC!!) so that i wont have to buy heat shrink tubing for 22.0mmØ bezels. Well, if i get a chance i would buy heat shrink tubing for my 21.5-23.0mmØ flashlight heads but until then, the Corsair rubber rings will do the trick of absorbing shocks from accidental drops: ( click to enlarge! )

I have learned from personal experience that the ANSI FL-1 STANDARD rating for impact resistance is worth a pos. I had broken my Xeno E03 V3 XML (shattered glass lens, plus short-circuited PCB by the violent swinging and impacting 14500 between the front and rear springs of the battery compartment) from 1.0m drops bezel down, although the Xeno company proudly published a video showing off the "1.0m drop resistance" .. which is a joke. It is a joke because in the video the Xeno engineer does not let the E03 hit the floor at all possible angles (e.g. what about 100% straight bezel down??), and what kind of ground is it anyway? Concrete company floor covered with green PVC? Doesnt look very smooth and as crystal-hard as bathroom marble tiles, huh. So why didnt he use a green carpet from the very beginning? If, after watching the video, you believe that the Xeno E03 is very drop-resistant, then they succeeded in fooling you. So my good advise is: Dont let yourself be fooled by such drop test videos (if they have a positive outcome) and for Christ's sake dont believe in published ANSI FL-1 STANDARD impact resistance data. Go figure, Klarus never published such data for the MiX6 (Mi10, MiX5, ..), and 4Sevens never published such data for any of their production lights (Quark, Preon, ..). It is good to know that Fenix takes ANSI FL-1 STANDARD measurements and tests very very seriously but it is in one's own responsibility to take measures to protect the lights against shocks, impact and drops. That's why the manufacturer often includes a lanyard, a wrist strap or a holster, right? Right.

The only light known to man to withstand drops 100% straight bezel down is the Rayovac Indestructible which has a ANSI FL-1 STANDARD impact resistance rating of 10m no kidding. The reason why its glass lens doesnt break is: the light has two rubberized ends (head, tail), and the glass lens is made out of plastic. Cheap construction with cheap materials and much glue but highly effective: Rubber doesnt break when you drop it!! Neither does plastic (in comparison to glass)! The disadvantage is: such rubberized lights can never be finalized in compact, beautiful and tiny designs as in our beloved Chi*a EDC lamps (DQG Tiny III, Quark, Fenix, ..):

Not a coincidence, the aforementioned Corsair company also manufactures a rubberized USB stick which has been an extreme selling success since its first market release. There you can observe as well: the rubberized USB stick is much bulkier and uglier than the elegant (yet rugged) blingy USB flash drive designs by the competitors. We learn from all this: Rubberizing is a common and known measure to protect electronic gadgets such as flashlights (Rayovac Indestructible, ..) or USB thumb drives (Corsair Survivor (ends) (Survivor worn o-ring dimensions: outer diameter 18.6-18.8mm, inner diameter: 14.9mm, thickness: 1.90mm), Corsair Voyager (whole body), ..) but they do make them (or their extremities) bulkier and uglier.

Minimally thin heat shrink tubing comes to the rescue!!

Since i dislike being afraid of dropping my lights and since i also dislike babying my lights, i am taking this protective shock absorbing measure to relieve my mind and release a good portion of worries. Otherwise i should be worried: the Klarus MiX6, the iTP A3 XP-G R5 Titanium and the Fenix LD01 R4 are current flashlight models, recently acquired, and very expensive for what they are .. primitive 1xAAA lights:

( click to enlarge! )

Once i've resurrected my Worm SS 2012, i will heat shrink some tubing around it too. The Tank E09 .. no protective measures for this inexpensive 1xAAA light! I got several copies of it (V1, V2), and i am going to buy more of it once the improved version is out (V3). So there is effectively no need to protect it with tubing ;)

Smooth surfaces. For smooth heads (polished stainless steel, or anodized aluminum with no bumps or grooves or effective knurling) i recommend using a thin rubber layer beneath the shrinkable wrap to enhance the friction on all interfaces. Where to get rubber tubing? Simply use the orifice of party balloons; in fact it has the perfect dimensions (diameter and thickness) to fit 14mm bezels. Without the rubber layer the shrunk wrap tends to loosen and lose its tension (tightness around the head). Why? Because the warmth of your inner pockets/pants expands the wrap, since heat expands matter as you know from physics. Rubber has high friction on all dry surfaces, so this idea works out very well, for example on iTP A3 which has a very smooth head with no effective knurling:

The idea was discussed in KLowD9x's thread Strongest keychain light.

How to shrink the tubing? - Very simple. By heat. Either by a heat gun, a hair dryer, a kitchen's stove, a home-made popcorn machine, or a lighter (zippo), candle, hot incandescent bulb, etc. In my case, i used a lighter and a candle with a very small flame. I do recommend using a tealight candle because you can easily adjust the size of the burning flame by cutting the wick shorter; a smaller flame is better for our purposes! It requires some practice to produce uniformly shrunk tubing with a flame because a flame is a 1-dimensional point source of heat whereas a heat gun (=standard machinery for heat shrink tubing!) is a 2-dimensional wall of heat. You can buy 1m of heat shrinkable wrap from any local hardware (or electronics) store. I went the ebay route only because my local electronics shop didnt have 16mmØ tubing in stock and I wasnt keen on buying his 19mmØ stock.

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Cool post, and nice pics.

FYI, you can turn the tubing inside-out if the printing is too distracting. My OCD forces me to do so.

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ChiX you've been using this flashlight protective technique too? :)

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Hah! I had the same thought when I saw the pics. Me thinks we have the same OCD.

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I have. I like to cover the pocket clips to prevent scratching, as well.

6

Nice descriptive writeup Kreisler. But dang those lights surely become visually challenging compared to the original slender and shiny look.

Does it not hurt you to put that on them? I could not do that to so sweet little lights. I would go have to take the standpoint " If it dies young - it becomes a beautiful corpse" :-)

BTW Me thinks the lights must be really poorly designed. I googled a little and the stories of AAA/AA EDC lights that die are plethora.

My EDC for several years ( 2,5 or 3,5 cannnot remember when I bought it - the first one that is) was the much beloved Sipik SK68. I dropped it several stories once ( litterally a 2 story drop) and I've dumped it in salt water, left it in 5 cm oil and used it the only way it likes to be used - on 14500 batts and for a full battery down to cut off several times in a 40°C + environment. It still works :-) So 10 USD well spent.

But what would BLF be without your entertaining articles and humorous views on these matters? Poorer - a lot poorer. So thank you for the idea and keep it up :-)

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"visually challenging" .. haha i like that. yeah, it hurt in the beginning.

now i enjoy it .. it's part of my fiddling with those little lights and some fun! if a light dies because of over-extended 10440 use, then it's acceptable (because i was warned by the manufacturer and fellow users) and i will feel sad only; but if a light dies or the glass lens breaks because i dropped it from 1.0-1.5m height, i will feel frustrated and furious and very angry at the manufacturer .. because they did state ANSI FL-1 STANDARD impact resistance on the retail packaging. Please note that 4sevens doesnt state such silly numbers and that Klarus doesnt specify drop resistance for the Mi-series (MiX5, MiX6, Mi10, ..). From a physics book:

As physics texts explain well in detail, matter doesnt break or fail because of drop height but because of the peak tension in the material x(times) its duration; and the key quantity here isnt the duration but the peak tension. The harder the ground (e.g. tiles, ceramics) the shorter will be the duration of the impact and the higher is going to be the peak tension, also called peak stress. Since the duration can never be infinitely short in the real world, the peak stress will increase with increased drop height. The softer the ground (e.g. asphalt, concrete, tar, PVC flooring, iron, steel!) the impact duration will be much longer with no force peaks at all, the result is: a flat graph of the force vs. time, and the impact is harmless, and that's what you see in the Xeno company-made videos of the Xeno E03 flashlight. The point is, the ANSI FL-1 STANDARD doesnt specify bathroom tiles or marble tiles as drop ground, and it is on such hard flat surfaces that any flashlight (glass lens, ..) fails, even from low drop heights < 1.0m, because only such super flat super hard surfaces generate top peak stresses in the impacting material.

I had once drop-tested the E03 on standard tiled floor and it failed after the 1st drop from 1m. ( I was furious about it, complained about it to XYZ and got a FREE replacement copy. )

Nowadays i enjoy my wrapped lights (i've ebay ordered heat shrink tubing for my 1xAA lights too!) much better since i can use them with a freer mind, less worries. it's like a big party.

haha

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I guess if you really want an indestructible light and have lots of money you could buy an HDS. Supposedly it was tested by dropping it onto rocks from 15' up and then throwing it a concrete walls as hard as possible for half an hour and it still worked and the glass didn't break. Very pricey though.

9

Ahh! Now I see why your operations aren't compromised ;) I was visualising a rubber sleeve the full length of the torch. I wondered how you could still use the twisty mech, this explains things. Thanks for the write-up :)

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Thanks for the information…