Leak testing flashlights

[tvodrd]

I did a quick search- no joy, so forgive me if this has been suggested before.

1. Remove the batteries- not for safety, to increase the air volume inside the light.

2. Put the light in the freezer with the cap or head loose enough to insure an unsealed condition. Let it get good and cold!

3. Fill a container (large enough to submerge the light) with hot water.

4. Open the freezer and quickly seal the cap/head.

5. Submerge the light in the hot water and watch for bubbles. As the cold air inside the light warms, it will attempt to expand and raise the pressure. /ubbthreads/images/graemlins/smile.gif

(Disclaimer- Most of the O-ring seal designs I see will seal bidirectionally. Some seal designs are specifically intended to seal best in a single direction.

Larry

 

[Deanster]

or you could just stick them in your hot tub like I did:

http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Board=UBB1&Number=478457

 

[tvodrd]

Hi Deanster,

I saw (and forgot /ubbthreads/images/graemlins/frown.gif ) that post. One advantage of the above is you can see where the leak if any is. Freezing first without batts also increases the pressure, and it will be air leaking out rather than water in.

(You submerged an M6! /ubbthreads/images/graemlins/faint.gif - that took stones! )

Larry

 

[McGizmo]

Larry,

Thanks for the tip! Since some of the seals are not bi-directional as you have stated, do you have any clever ideas on testing for pressure? Heat the light instead and then look for moisture going in after you put it in cold water?

It seems to me that an optimal design would be one that is sealed against external pressure, but burps readily if you have an internal pressure build up (gassing of the batteries, for instance) /ubbthreads/images/graemlins/icon3.gif /ubbthreads/images/graemlins/thinking.gif /ubbthreads/images/graemlins/wink2.gif

 

[BatteryCharger]

I tried putting a mag at the bottom of my pool. It stayed lit and I didn't see any water looking in the lens, so I thought it was ok. I opened it a week later to change the batteries, and dumped out a few ounces of water. /ubbthreads/images/graemlins/rolleyes.gif Now it's all corroded inside and the light flickers when I focus it...

 

[McGizmo]

BatteryCharger,

I have had the same problem with a few lights. They don't necessarily suffer from a catastrophic flood but may have some water ingress in an area not visible from outside.

On a similar note, the design can be flawless but foreign objects or pinched or nicked O-rings and seals can spell disaster. /ubbthreads/images/graemlins/icon15.gif Been there and done that! /ubbthreads/images/graemlins/eek.gif

 

[tvodrd]

Don,

I can't recall seeing a directional seal on a flashlight, but I have zero experience with dive lights. The simplest have "lips" which the pressure forces tighter against their sealing surface. Do dive lights incorporate these types? I believe that O-rings with proper glands/compression/lubrication are about the best available solution for our lights.

As to pressure relief, there are very inexpensive molded rubber "umbrella valves" which can be used as both check or relief valves. Might be a little tricky to get one into an Arc AAA, which seems to be the only place I've read they may be needed. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/wink2.gif

Edit: Seems to me the worst case for a directionally-sealed dive light would be a false positive in the described test. /ubbthreads/images/graemlins/icon15.gif

Larry

 

[The_LED_Museum]

I usually test flashlights for water-resistance by dropping them in the sink or toliet bowl (usually the sink).
Positive pressure on the outside of the light, where the water is trying to enter, is what I'm looking for in these tests. If the O-ring (or multiple O-rings) are doing their job, the flashlight should not admit water at depths of a foot or so. I'm not equipped to test at greater depths; so these tests are left up to somebody who has access to water deeper than about a foot.

My Pelican Sabrelite 2020 is equipped with an obvious umbrella valve; however I am not equipped to test it. This test would have to be up to somebody with venting (bad) batteries, a Pelican Sabrelight, and access to water where the flashlight can be watched for bubbling - which might take awhile. This valve is triggered by internal air pressure greater than what can be achieved by sealing your lips around the open end of the flashlight and blowing into the flashlight barrel.

 

[Deanster]

Most current dive lights have some sort of relief valve as well as catalyst pellets - Pelican has it across nearly their entire dive-rated line now.

I was just being a wise guy in my post up top, but it's actually a reflection of my overall philosophy that you should directly test the quality or qualities you wish to learn about to the greatest extent possible.

If it's water intrusion that you're worried about, it's intrusion that you should test - I've said here many times that I think manufacturers should test lights for the electronics industry submersion standard of one meter for 30 minutes.

While the idea of creating gas expansion inside the light to test the seal is very cool, I wonder a bit about how much you really learn - I'll leave the calculations of how much pressure could be created inside an E2e from a temp shift from 30*F to 80*F to someone else, but I think it would be less the pressure differential from one meter submergence.

(Somebody please correct me if I'm wrong!)

Anyway - I've got in mind a project to take out the old boat onto the lake, and submerge the same batch of lights as the last test to 30 and 60 feet for, say, 15 minutes at each depth, and see how they do... I might leave out the lamp assemblies, though, as I wouldn't be able to test switching....

I'll let ya know if it actually happens!

 

[tvodrd]

Hi Craig,

Each 27.68" of water depth = 1 psig. (That ones im memory.) It's a rare set of human cheeks that can make 5psig. /ubbthreads/images/graemlins/icon15.gif Boyle's law will calculate the internal pressure rise from the described test. I haven't bothered- requires temp in Rankin and I'd have to hit the books again.

Larry

 

[McGizmo]

Larry,
I haven't *seen* any either but I have an idea in mind.... /ubbthreads/images/graemlins/tongue.gif

On the other hand, the E battery tube to head O-ring seal is likely more sound in an external pressure greater than internal differential because of the pocket clip issue.

 

[BC0311]

/ubbthreads/images/graemlins/popcorn.gif

 

[tvodrd]

Don,

I concur. I think with the E-series the internal chamfer for the threads in the head serves to squeeze the O-ring radially inwards against the body and the support provided by the plastic "insert" definately helps. External pressure should tend to force the O-ring harder against the chamfer and body. Internal pressure would force it against the chamfer and body face which includes the "insert." As a static seal, I would predict a capability of at least 100 psid in either direction. /ubbthreads/images/graemlins/icon3.gif (And that's pretty deep! /ubbthreads/images/graemlins/grin.gif )

Larry

 

[Rothrandir]

[ QUOTE ]
tvodrd said:
Hi Deanster,

I saw (and forgot /ubbthreads/images/graemlins/frown.gif ) that post. One advantage of the above is you can see where the leak if any is. Freezing first without batts also increases the pressure, and it will be air leaking out rather than water in.

(You submerged an M6! /ubbthreads/images/graemlins/faint.gif - that took stones! )

Larry

[/ QUOTE ]

he may have stones, but he's sure as heck lost his marbles /ubbthreads/images/graemlins/grin.gif

 

[NikolaTesla]

You are one brave dude, Deanster. I wanna read this review SureFire lights sent to 60 Feet! I would trust my UKE LC100 but SureFire states it cost extra for the Navy SEAL modification. Good Luck.....

NikolaTesla /ubbthreads/images/graemlins/wink.gif
An Arc lamp is the Spark that takes away the Dark--

My Lights:

http://www.tjtech.org/gallery/NikolaTesla

 

[Lurker]

This freezer thing is an interesting test and as long as you understand the limitations, I think it can really tell you a lot about the quality of the seals. It's not perfect, but it's a lot better and more practical than anything else I have heard.

Interestingly it is similar to how a watch is tested for water resistance. In the most common test, the watch is suspended in a sealed jar that contains water. The watch is kept dry above the water level. The jar is then pressurized. At this point if the seals are weak, the high pressure air will seep into the watch. The watch is then lowered into the water and the pressure is released from the jar. If the watch bubbles, then it failed the test.

The key difference between these two tests is that with the watch test, the air must leak both into and then out of the watch, whereas in the freezer test, the leak is only outward.

One of these watch testers would be great for testing flashlights, but only the smallest flashlights would fit inside, and they are pretty expensive. Maybe someone could figure out how to rig up something similar out of cheap components.