The topic shows up from time to time….
Most zoomies are not waterproof. The reason is that while zooming, they need to move air in and out of the body which doesn’t allow them to be fully sealed.
I wanted to compile a number of ways to let the air in and out while not letting water in. Or to otherwise make the light give at least very basic waterproofing guaranties.
1. Tight o-rings.
With this method zoomie is sealed while the bezel doesn’t move but breaks the seal while zooming
Pros:
- cheap
- simple
- tried and tested
Cons:
- very stiff zoom travel
- not fully waterproof while zooming
2. Internal zoom, camera-lens style
With camera lenses there is no air movement in and out, so the body can be fully sealed
Pros:
- tried and tested (in cameras)
Cons:
- expensive
- bulky
3. Internal zoom, enclosed lens
One can build a regular zoomie but enclose the entire bezel in another box. That other box can be waterproof because again any zoom travel doesn’t change volume of the light
Pros:
- works well under water
Cons:
- bulky
- somewhat less throw due to smaller lens
4. Secondary internal lens
Don’t try to waterproof the entire interior but only the electronics. Put a flat waterproofing-lens below the main one, fixed to the main body. The light is much like a mule with a moving aspheric put in front of it. Note: you can use a pre-collimator lens instead of a flat one. Either TIR or spherical.
Pros:
- quite simple
- reasonably compact
Cons:
- applicable only to aspheric zoomies, not TIR ones
- water ingress below the lens may force interior cleanup
5. Fixed lens, moving pill
Volume doesn’t change, so no problems with waterproofing the lens.
Pros:
- I fail to find any
Cons:
- the light is always in the largest position which adds bulk
- moving the pill is complex, especially if it’s done in a waterproof way
- poor thermal path from pill to body
6. Lock-seal
Seal that engages only when the bezel if fully retracted. The light is waterproof in flood mode, but not in throw or intermediate. You probably want to store the light retracted anyway, so it’s waterproof then.
Pros:
- quite simple
- compact
- cheap
Cons:
- not waterproof while zooming
7. Membrane
Gore-tex style membrane allows air to move in and out but keeps water out
Pros:
- compact
Cons:
- untested, novel, may or may not work well
8. Conformal coating
Let the water in but protect the electronics by:
- coating the LED and wires with something waterproof (except for LED lens obviously)
- sealing wire holes and pill (if there’s one) so water can’t enter driver / battery compartment
Pros:
- compact
- lightweight
- inexpensive
- does not have to be designed into the light - can be applied by modders
Cons:
- any water ingress may leave residue on LED dome so you’d better clean it up with IPA after such event
- makes LED swaps more effortful
9. Driver seal
Like above but don’t apply conformal coating. Be sure to use a driver with LVP and thermal protection.
Pros:
- simple
- compact
- lightweight
- inexpensive
- does not have to be designed into the light - can be applied by modders
Cons:
- any water ingress may leave residue on LED dome so you’d better clean it up with IPA after such event
- water can cause a short. The light will stop working then and battery may discharge. But current is still regulated by the driver and can be reduced when the light overheats. This should be enough to prevent damage.
10. Variable-shape lenses
A lens that changes shape to provide zoom
Pros:
- cool
Cons:
- expensive
- low performance (the working area of the lens is very small)
- untested