does potting have a thermal impact though?
seems like if you just potted an existing light, you might screw up some of the assumptions the designers made about thermal paths, resistance etc…
wle
Potting, especially with a thermal epoxy, will improve the thermal handling. Generally speaking air is an insulator so unless the epoxy is designed for insulative properties it should be an improvement.
The issues were usually people. lol
Like, build a light with 4 modes and last mode memory, pot it, test it, ready to ship out… they say Oh no! I wanted 3 modes and no memory! UGH! Of course it is almost always in writing, the original requests and all correspondence, but you know how it is…
Here it sounds like you know it makes the light tougher.
Here is seems like it doesn’t.
I think most would agree that two lights that are identical will always be tougher when potted.
Again, define tough.
Potting it won’t make the glass lens stronger. Won’t improve the springs or make the pcb less likely to fracture. Even embedded in the potting media, some components can and will fail. How do you fix it then? The impact or extreme vibration that warrants potting can indeed cause Cap’s to break, especially the stupid yellow ones. Or a cold solder joint to crack and cause flickering. Potting isn’t the end all be all.
No, potting it wont make the glass lens any stronger, I heard that is why Malkoff switched to acylic. No, it wont improve the springs, but like already mentioned battery stops will fix, or highly mitigate that issue. When potted in thermal epoxy the light will withstand more drops, shock and abuse than a non potted light that is exactly the same. Potting isn’t the end all be all but it sure does make the light tougher, and by tougher I mean less likely to have any components fail that will cause the light not to work. The OP is asking for a cheap light that can be made tougher by potting it. So if something does break inside, (which is more likely with a cheap light than a Malkoff, Elzetta or Surefire. Yes I know Surefires are not fully potted just conformal coated) then getting inside the light is no problem, because it only cost 30-40 USD. Just buy another one if there is no warranty. If it fails in a Malkoff or Elzetta, you have a lifetime warranty.
The light thrown out of the window at 60 MPH would have been fine with simple battery stops, or bumpers and the cell would have been also. The Elzetta video shows a tough light in my opinion.
Now, having said all that, for the O.P. is it possible to get a well engineered light and have a manufacturer pot it for cheap? IDK if that is possible, but I do personally think it will make it tougher. Like you said about your customers throwing them in the back of a truck, so you potted them to make the lights stand up to more abuse/shock.
How much would it cost for a cheap 30-40 USD light to be potted by the maker? Mentioned above Armytek does it and they are some models are not really expensive, your paying mostly for time. I would buy some cheap Convoy lights that were normally 14 USD and potted were 25 USD. https://youtu.be/1ozstdsnHNs
Talk to Simon, see if he’d agree to do a Tactical S2+ or C8 with potting. He just might go for it for the extra $10 a pop…
From Elzetta:
Elzetta Modular Flashlights have earned the title, “The Toughest Flashlights on the Planet”. They have been used as hammers, shot with shotguns, and dropped from helicopters. Elzetta Modular Flashlights are not just tougher than other flashlights, they are orders of magnitude tougher than other flashlights. The key to this extreme durability lies primarily in two factors. First is the solid acrylic optical lenses (see blog on Beam Projection for more information). The other key ingredient is fully-potted electronics.
To understand the importance of potted electronics, one must have a basic knowledge of circuit board construction. In the simplest terms, a circuit board is comprised of electrical components held to a fiberglass/copper board by thin solder joints. The solder is made of a tin alloy which, by nature, has very poor mechanical properties. With solder joints in modern electronics commonly measuring less than 1 mm in thickness, the force required to break these spindly tin connections is pitifully small. A short drop to the floor is often adequate to fracture a solder joint which, in most cases, will render the circuit board in operable.
Enter electrical potting. This technology has been around for decades and is used to harden many aviation and critical military electronics. Potting compound is a thermoset substance that is applied in liquid form and subsequently solidifies to a rigid structure with strong mechanical properties. When dispensed into a housing that contains electronics and/or circuit boards, the liquid potting compound fills the housing and flows around every electrical component and every solder joint. The potting compound then hardens and locks everything together into one solid structural mass. (It’s a bit like pouring concrete on a miniature scale. Once the concrete has cured, there is no way the rebar is going to bend or break.) An electrical device without potting is only as strong as its weakest solder joint. A device with electrical potting is vastly more rugged as the solder joints are completely surrounded and reinforced. The additional strength supplied by the potting compound not only increases load bearing capabilities, but also resistance to shock, impact, and vibration.
Additionally, potting compound provides a hermetic seal for the encapsulated electronics. This keeps all electrical components completely protected from water and other fluids that can quickly destroy unpotted devices.
It is hard to overstate the robustness that potted electronics bring to Elzetta Flashlights. As stated before, Elzetta Modular Flashlights are not just tougher than other flashlights, they are orders of magnitude tougher than other flashlights. Other manufacturers boast of 1.5 meter drop tests (less than 5 feet) while Elzetta Modular Flashlights have survived 300-feet drops. Other manufacturers claim waterproofing to depths of a few meters relying on o-rings to keep water away from vulnerable circuit boards while Elzetta Modular Flashlights can be submerged to nearly any depth for any amount of time as the electronics are fully encapsulated inside the device.
I’m now speculating on the robustness of a 21700 light with:
- an 18650 cell in it
- 1.5mm thick o-rings on the cell to stop it rattling and cushion it sideways
- fat 2mm or 3mm thick o-rings inside the tube at each end as cell bumpers
- longer springs probably needed as well
A very interesting thread, thanks everyone, and a special mention to Dale for the videos!
Here is the video version 
The Key to Extreme Durability; Potted Electronics in Tactical Flashlight, Elzetta vlog episode 7 - YouTube
And while on this matter I may know better, potting does not need to be indiscriminately done in order to improve toughness in a flashlight. It could also be done with some sort of removable stuff via gas/turpentine bath or sort of, like some thermal glues. But it seems it is also done, as DB Custom says, to make 'em tamper-proof modification-proof trash ready.
No, I do not buy expensive trash ready flashlights. Vade retro, satana! :-D
:-)
Actually…it may. 
Or, strictly speaking, support it rather than reinforce.
There are optically clear silicone based potting compounds. I’ve fantasized about having a reflector light where not just the driver but the entire head is potted.
But then….you showed me this Eagle Eyes. With improved springs its toughness would probably be overkill already. Simpler, cheaper, lighter, repairable, upgradable.
That was just a single test. If I trusted the light to be able to sustain many milder (say 4m freefall) drops - I would call it the right way for almost all BLF lights. Almost - because of indication that weapon lights need to be potted nevertheless.
As of now I’m still a little unconvinced, I feel I’ve seen too little evidence to say that a well done unpotted light can be seriously tough. I consider it likely rather than certain.
BTW, I wonder why thermally or chemically toughened glass lenses are so rare…
One more thought about the DB Custom experiment.
The initial hit was on the tail. That’s where the PCB is supported. The head side got much weaker hits.
Dale…do you know which spring collapsed? Was it front or rear?
I was not a big fan of the way Emisar does the driver assembly.
Glue?…meh.
But now I think that glue is actually an elegant way to transfer impact energy from the spring to the body, as long is it’s hard. In X6 or FW3A or any other light where the driver is held by a retining ring alone there’s an air gap between the driver and the shelf. What happens on impact?
Driver PCB takes the energy at the centre and transfers it to the body at the sides.
If deforms while doing so. Hopefully not enough to make components hit the shelf. But even if the light is designed with large enough air gap, the deformation is likely to cause some micro damage to the glass firbres inside the MCPCB. And repeated hits will make it crack.
Glue…as long is it’s not elastic (f.e. soft silicone would be a bad choice) takes the impact energy and transfers it directly to shelf. There are only compression forces and these are not really problematic for PCBs.
Initially I thought about silicone thermal pad…but differences in heights of driver components make it bad. And transfer occurs mostly through the components. And regardless of thermal pad harness - the higher components take much larger forces than the lower ones. Overall…I don’t think it would work.
At the time of this post there are a high percentage of people here who would like a potted budget light. 68 votes (79) say yes 18 votes (21) say no.
I think if we make the lights very well, and at a very affordable price point, that number has the potential to rise a lot.
So the next step is, what budget light do people want to see thermally potted? We might need a post/poll for that and see where we stand. Possibly offer four or five models and be open to suggestions as well, then narrow it down.
My favorite flashlight durability video. I have one of these. I don't doubt they are as shock proof as they claim - based on these two videos. The only downside - it's a pain to replace the batteries - you will need a screw driver.
Only a 14.5K pound fork lift could make it fail (partially).
I thought it was a joke at first the way they were talking. LOL!!! It does look like a good work light for working on a car or other things though.