Any interest in a potted BLF light?

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ValuseekeR
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Any interest in a potted BLF light?
Yes
79% (68 votes)
No
21% (18 votes)
Total votes: 86
ValuseekeR
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Kind of a random thought, but I’ve seen several threads about durability/reliability lately.

Has there ever been any talk about developing a “budget” community light for folks who are interested in having at least one light built with durability prioritized over being moddable? Would it even be possible to offer a potted light with high-end features (emitter choices, UI, etc…) in say, the $30-40 range?

bmengineer
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Realistically, Armytek sells potted lights at this price range with exactly the UI I’d want in an emergency light, when they go on sale – I paid $35 for my Partner C4 Pro.
If we could convince them to use a high CRI emitter and do a group by at that price in a light like the Partner C1 or C2, and use the right optic, I’d be very interested. If you’re talking about just filling a FET light from Astrolux or Sofirn with silicone, I still wouldn’t trust it to take a beating.

Find all my reviews of flashlights and more gear at www.bmengineer.com

Ozythemandias
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Potting matters less for overall durability than the actual design, quality of components and consistency of the manufacturer’s production.

Anyway, there probably is an interest in this, it’s what motivated the Sofrin C01 development.

Paradise
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In the first instance, I would like to know about the design principles of potting and/or that of a durable light. Then I would want to hear more how that proposed solution meets all of these. If the price is high-ish, could be cheaper to just buy an available product?

Since I already have plenty of lights – how difficult is potting the existing herd?

ValuseekeR
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I’m definitely more ignorant than knowledgeable here, mainly interested in some discussion.

I’ve looked at the Pflexpro S2+ a few times, but they’re fairly expensive (I understand it’s a small shop,) the store is currently down, and while I’m an S2+ fan, they’re a bit big for edc. Will definitely look into Armytek, but just got to thinking about this again after ordering my FW3A this morning.

Design and production quality are important, but assuming they’re on point, proper potting should make a well-built light nigh indestuctible from vibration or impact, correct?

Diy may be feasible, but I’d generally rather just buy one that came that way.

Caleb
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Hmm… a potted light could be designed for easy emitter swaps… allowing some modability.

DB Custom
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So the real question is, what makes a light reliable or indestructable? It isn’t simply potting. the electrical components have to be high quality, capable of running the light at it’s design specs for a lifetime. Potting is good for a weapon mounted light, not so much any other reason.

Case in point, Eagle Eye built an X6 for cheap monies with a military grade type III hard coat. Super tough relatively small light. While everybody else was drop testing it and driving over it I tossed it out the window of a car going 60 mph. The light got a slight few scrapes but was comparatively undamaged, the only real damage was that a couple of the impacts (I video’ed it) collapsed the springs so the light quit working. I replaced the springs and the light is good to this day (years later) Now , had it been potted it likely would not have been possible to replace the spring on the driver and the light would have been trash.

I’ve modded potted Army Tek lights too, they even stole my pictures because they had never seen inside their own light! Designed in Canada, made in China… they warranty by throwing away defective lights and replacing them.

So that, ultimately, is what potting does for a light… makes it gun proof and trash ready.

Oh, I’ve potted my own builds before, and I’ve cut through a driver on the lathe to get back inside and rebuild it. Manufacturers like to pot as a warranty measure, lock it in so people can’t mess with or copy their design, and for that I can hardly blame them.

Good gun mount potting is NOT silicone, normally those have a black epoxy that is hard as a rock. You just aren’t gettin in that one and have the driver remain intact. And for this flooding of epoxy, well, normally it comes at a price…

Good luck!

Nichia
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Caleb wrote:
Hmm... a potted light could be designed for easy emitter swaps... allowing some modability.

 

 

 yes please! 

Nichia!

ValuseekeR
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DB Custom wrote:
So the real question is, what makes a light reliable or indestructable? It isn’t simply potting. the electrical components have to be high quality, capable of running the light at it’s design specs for a lifetime. Potting is good for a weapon mounted light, not so much any other reason…

Good luck!

Thanks for the post DB! Definitely a lot of good food for thought there.

I’ve had many lights fail over the years after seemingly trivial impacts or for no discernable reason at all (to me anyway). This had led me to question the durability of flashlights and to baby the ones I have now as a result.

Maybe potting isn’t as straightforward a solution as I thought, but I’m also not immediately convinced that it’s really only warranted for weapon-mounted lights either.

The prospect of manufacturers making more inexpensive spare parts available is a positive and another possible point against potting, but at the end of the day I’m interested in what it takes to make an affordable light that won’t break in the first place.

And yeah, I could “afford” to buy more expensive lights with a good warranty or whatever, but there are other reasons I don’t really want to go over ~$30-40 on a light in general these days. In the meantime I’ll start researching the most durable budget lights.

Agro
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ValuseekeR wrote:
DB Custom wrote:
So the real question is, what makes a light reliable or indestructable? It isn’t simply potting. the electrical components have to be high quality, capable of running the light at it’s design specs for a lifetime. Potting is good for a weapon mounted light, not so much any other reason…

Good luck!

Thanks for the post DB! Definitely a lot of good food for thought there.

I’ve had many lights fail over the years after seemingly trivial impacts or for no discernable reason at all (to me anyway). This had led me to question the durability of flashlights and to baby the ones I have now as a result.

Maybe potting isn’t as straightforward a solution as I thought, but I’m also not immediately convinced that it’s really only warranted for weapon-mounted lights either.

The prospect of manufacturers making more inexpensive spare parts available is a positive and another possible point against potting, but at the end of the day I’m interested in what it takes to make an affordable light that won’t break in the first place.

And yeah, I could “afford” to buy more expensive lights with a good warranty or whatever, but there are other reasons I don’t really want to go over ~$30-40 on a light in general these days. In the meantime I’ll start researching the most durable budget lights.


Please let me join you in thanking DB Custom – ineed a very interesting post.
texas shooter
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DB Custom wrote:
So the real question is, what makes a light reliable or indestructible? It isn’t simply potting. the electrical components have to be high quality, capable of running the light at it’s design specs for a lifetime. Potting is good for a weapon mounted light, not so much any other reason.

Good gun mount potting is NOT silicone, normally those have a black epoxy that is hard as a rock.

This what got me potting a few lights. I’ve also found another reason, it’s water proofing and to some degree strengthening perpendicular board-to-board connection. I picked up a few Mateminco TK01 lights. A great and over looked light in my limited opinion. It’s got one glaring weakness. It’s charging port is too open. Meaning a gap around the Micro-USB leading right inside. I potted one for the pool test with the port cover off. After two days at 7 feet it came up dry inside.

Virisenox_
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Related to previously asked questions, but what kills a flashlight when it’s dropped? I assume it’s just components coming loose from the impact, right? I think I read somewhere that linear 7135 based drivers tend to be more durable for that reason, because all of the components are fairly low profile.

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Paradise
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My S2+ lights get dropped all the time, like all-year-round. So far, nothing has ever happened to them? The cells look a bit dented, but that will buff out Big Smile
Lights are fine.

So what would potting bring in addition to the regular protection? Higher drops? break-resistant lens? different solder?

DBs post was excellent and gave me details I needed.

KawiBoy1428
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You need to restrict the movement of the battery from impacting the driver spring, which when bottomed out (coil bind) impacts the driver, Potting also aids in thermal transfer if you use the right stuff.

KB1428 “Live Life WOT”

Agro
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A related question:
In the future BLF projects…what can we do to make sure the lights are tough?

Agro
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KawiBoy1428 wrote:
You need to restrict the movement of the battery from impacting the driver spring, which when bottomed out (coil bind) impacts the driver, Potting also aids in thermal transfer if you use the right stuff.

Do you mean that the spring should be long and stiff or that it should be short and not move much (like Emisar…or even more – DQG)?
KawiBoy1428
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Agro wrote:
KawiBoy1428 wrote:
You need to restrict the movement of the battery from impacting the driver spring, which when bottomed out (coil bind) impacts the driver, Potting also aids in thermal transfer if you use the right stuff.

Do you mean that the spring should be long and stiff or that it should be short and not move much (like Emisar…or even more – DQG)?

Not really…. battery/cell stops in the battery tube, a shoulder restricting the cell from going too far forward on impact/recoil…usually a shoulder with an o-ring to eliminate abrasions to the cell wrapper.

.

. Even a bumper on the tail cap….limits movement allowing the spring(s) to maintain contact

.

KB1428 “Live Life WOT”

Agro
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Smart. Smile

BlueSwordM
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Or just use dual BeCu springs. Smile

They resist deformation against shocks extremely well, even in heavy lights.

One example of this was when I threw my Q8 on concrete. By accident of course. Smile

Didn’t turn off at all during the bump.

Even hitting it on a wooden table with all my might couldn’t shut the light off.

My very own high current Beryllium Copper springs: http://budgetlightforum.com/node/64047
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

KawiBoy1428
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Agro wrote:
Smart. Smile

It is easy to do with the Surefire lights because they are all mostly CR123 powered and have to be bored for the 18650/350 cells, even my 6P mods can be weapon mounted, I machined a battery stop into the battery tube on the head end.

.

.

. Then polish the battery tube for a tight slip fit for certain cells like the VTC5A’s I use.

. Came up with a quick change module system fully potted driver, copper sink and reflector, the whole head is thermally potted and can be changed out from 2 different battery tubes depending on what emitter head I want to run.

.

.

.

.

.

KB1428 “Live Life WOT”

KawiBoy1428
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BlueSwordM wrote:
Or just use dual BeCu springs. Smile

They resist deformation against shocks extremely well, even in heavy lights.

One example of this was when I threw my Q8 on concrete. By accident of course. Smile

Didn’t turn off at all during the bump.

Even hitting it on a wooden table with all my might couldn’t shut the light off.


Usually the batteries will get damaged. I have a few batteries with dents from lights falling hard enough to break the lens and smash the flat top in from the spring bottoming out. Restrict the battery movement = less damage.

KB1428 “Live Life WOT”

BlueSwordM
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That’s why it’s so nice.

Your idea is better though.

The problem with springs is that not all of them are made equal.

Steel wire springs are good springs, but they don’t absorb a lot of energy on impact, meaning the cell has to absorb a lot of kinectic energy from impact.

BeCu springs are different since they take much more force to compress, depending on wire thickness and the number of coils, along with top diameter to bottom diameter ratio.

A large thick 1mm BeCu wire spring will take beating like a champ. A smaller 0,5-0,7mm BeCu spring will protect the cell, but might collapse.

My very own high current Beryllium Copper springs: http://budgetlightforum.com/node/64047
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

ValuseekeR
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Really appreciate ALL of the replies so far, very interesting and informative. Thumbs Up

CREEXHP70LED
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KawiBoy1428 wrote:
BlueSwordM wrote:
Or just use dual BeCu springs. Smile

They resist deformation against shocks extremely well, even in heavy lights.

One example of this was when I threw my Q8 on concrete. By accident of course. Smile

Didn’t turn off at all during the bump.

Even hitting it on a wooden table with all my might couldn’t shut the light off.


Usually the batteries will get damaged. I have a few batteries with dents from lights falling hard enough to break the lens and smash the flat top in from the spring bottoming out. Restrict the battery movement = less damage.

I agree with what you have said. I have my first 2 Malkoff lights arriving tomorrow, and I ordered the battery bumper kits for both lights, and of course they are potted. I understand these are not budget lights, but it isn’t expensive to add a couple o rings to the front and back of the light. Then if you have a solid built light and you pot it, your good to go. Just as long as your not looking to mod it.

 

 

 

KawiBoy1428
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Malkoff’s are double thermally potted and done very well, a copper shelf, potting, driver with brass battery contact/sink, potting, spring. Heavy duty to say the least.

KB1428 “Live Life WOT”

Agro
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I view it like that:

1. Battery stop
Initially the spring compresses, transferring some impact energy to MCPCB. Then there’s stop which quickly transfers the rest of impact energy directly to the body.
2. Stiff battery
All the energy is transferred to MCPCB but unless the spring bottoms out – the transfer is much smoother and peak forces much lower.
BlueSwordM, did you try to bottom out with protected cells? That should be easier to do.

Big force on the driver will make it crack. A little smaller – will make it bend. Repeated bending will make it crack eventually.
Intuition tells me that both long stiff battery and a stop should work well enough. Note at the tail cap there’s a similar issue. Though I think it’s easier to support the tail PCB with the tailcap wall, at least in lights that don’t have tail switches.

But that’s not all of it.
F.e. this light died due to a sideways impact. Managing battery impact wouldn’t help.

This may be related to

"Virisenox_" wrote:
Related to previously asked questions, but what kills a flashlight when it’s dropped? I assume it’s just components coming loose from the impact, right? I think I read somewhere that linear 7135 based drivers tend to be more durable for that reason, because all of the components are fairly low profile.

But there’s also another thing making me think this is not a full picture. DB Custom’s EE X6 experiments. A spring collapsed there so it was not very stiff and there was nothing that would prevent it bottoming out. Yet the driver (as well as the tailcap) survived despite being directly hit with a cell multiple times.

Agro
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I did a bit of learning on solder joint failure in drop shock. It happens to be a rather well studied topic and there’s even a standard way of measuring resistance (JEDEC JESD22-B111). In the era of everyone carrying one and often more electronic devices with them, drop resistance is a common requirement.

It is often said that SAC305 is not great for shock resistance. Though in most studies that I’ve seen it’s actually a great performer. There’s a number of specialized alloys that target high shock resistance, typically proprietary with undisclosed composition. I’ve seen indication that these are low-silver products.
F.e. Indium’s SACM is Sn0.5Ag1.0Cu0.03Mn

PCB finish matters.

Overall…the disconnect between common recommendations and study results that I found makes me feel that I don’t have any idea of what’s going on.

Interesting read:
http://www.circuitinsight.com/pdf/reliability_comparison_lead_free_smta.pdf
http://www.techni-tool.com/site/ARTICLE_LIBRARY/Indium%20-%20Choosing%20...
https://alphaassembly.com/-/media/Files/CooksonElectronics/Drop-Shock-Re...
http://www.circuitinsight.com/pdf/Effect_Solder_Composition_PCB_Surface_...

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Well, I probably forgot what actually happened in the X6 road test… the cell compressed the cell to it’s max and then dented in the top of the lap pull cell. This made it too short to reach the spring, so between some spring collapse and the dented cell the light wouldn’t work. I still have that cell and that light, both still work. But at the scene, under an extreme duress, the light did actually fail.

My thought to do the test was remembering those times something got left on top of the car, or on the toolbox on the truck, even on the bumper of the truck after looking underneath. So the 60 mph test was an extreme real world possibility. The light survived, took very little to resume working condition. Again though, had it been potted it might not have been repairable.

The Type III ano actually survived sliding on asphalt quite well, the major damage came when a pebble in the surface started the light flipping and it rebounded into the air then impacted very hard at landing. Comparatively minor damage even then, but the sliding action that could be heard in the video did virtually nothing to the light.

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I found the two video’s relevant to this conversation, uploading them to YouTube… it was September 06, 2014. Wink

Agro
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Spring collapse may be fixable – get stronger springs or go springless. Smile
Performance of the rest of the light is remarkable and it would be good if future BLF lights could match it. Or exceed it. Smile
[ADDED]
I mean: it doesn’t feature Elzetta-like wall thickness. It’s not made from high-end alloy. It doesn’t use potting. It doesn’t use any exotic construction. It’s not expensive. There seems nothing special about it but nevertheless it performed incredibly well. Maybe they just did something right…and I’d really like to know what it is.
Though seeing that was a single test of a single specimen makes me wonder if the result was not a pure luck. I guess we won’t be able to do tests at scale though…
[/ADDED]

I’m looking at X6 disassembly pics now.


Looks like there’s a generously sized ring for the driver to sit on. The driver doesn’t seem to be supported from the centre of its back which surprises me slightly. I wonder what’s the driver PCB thickness…

At the tail it looks like the spring presses on PCB which presses on the switch which presses on alu ring which presses on tailcap. So it’s complex but there is some support directly behind the spring.

BTW it just occurred to me that Zebralight or similar light engines are inherently safe against the batery damaging the driver – because it’s easy to make positive contact supported directly by the shelf.
Combine this with DQG style springless construction you have fat contacts at each end (which means relatively small chance of denting the cell) and the result seems very robust.

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