SureFire uses a variety of methods to ensure it's flashlights can recover from being flooded - anodising, Chem-coating, conformal coatings for the electronics, plating and such for other components.
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Al
Bold emphasis added by me.
As I understand the designation, waterproof, at least as Ralph Nadar and crew intended, an item is waterproof if it can be subjected to water and continue to function properly. In the case of a watch, the watch had to be able to survive a flood with all components getting wet, and continue to function properly. That is a tough act to perform.
I was real impressed to find that SF had gone to the extent they did in researching conformal coatings and implementing them on the electronic circuits. This would be a mandatory step in truly making a light waterproof but I don't think any light is really waterproof and especially if the water is salt water. I know of no existing reflectors which can be subjected to salt water and continue to perform as they should. Perhaps a light with an optic lens or TIR might qualify. I have my doubts that any of the LED's can be subjected to saltwater under pressure and not be adversly effected to some extent. If you have an electric potential present in a salt water flood, the electrons will flow in places unintended and they will induce galvanic corrosion in real time!!
IMHO, one aspect to a good dive equipment design is consideration of a flood event and addressing the ease of replacement of those components that would likely be compromised in such an event.
A fresh water or even fresh muddy water flood would be much less destructive to a light and a clean water rince may be all that is required. A light could be flooded in fresh water and continue to operate in some cases. I am guesing that the A2 which was the subject in the OP was flooded with fresh and not salt water.
To my way of thinking, the water, fresh or salt, is more significant in consideration than given credit by most people or manufacturers in their claims. I have taken some aluminum lights (not dive lights) into the ocean and had them function properly and not flood. However, saltwater got into areas which were not cleared out sufficiently upon a fresh water rince and over a short period of time corrosion took place. I have experienced this with lights of my own build, some SF lights, a Gladius and a limited production light of one of our own CPF members. It is my opinion that aluminum in salt water must have a good hard anodize film and in any areas that this film has been compromised or is not present, corrosion will occur unless all salt is removed immediately. If there is current passing through any area that is not electrically isolated by a hard anodize film, you will have galvanic action.
I believe a light can be considered fresh water safe but not saltwater safe. This is true regardless of whether the light floods or not but certainly in the case of a flood, the stakes are much higher!
Ironically, the UW camera housing I mentioned in a post above is for the most part waterproof. That is to say that a flood of salt water doesn't really damage it. It does have an electronic circuit with its own battery that functions as a leak or flood detector. There is a red LED that blinks when the circuit's probe senses water. Cool except that this circuit doesn't have effective conformal coating and after a single flood of only a couple drops, if these drops flow over the circuit, the circuit dies!! :green: Oh yeah, the housing is waterproof but of course in the case of a serious flood, the camera within is toast as is the lens! Easy to remedy though. Just replace camera and lens and away you go.
