DIY Submersible LED Flashlight

[mbram]

Article here:
Make: Online : DIY $5 LED dive light

Video here:
MechanicalMashup Episode 20

Basically he's filling the inside of an LED flashlight with a non-conductive liquid, mineral oil. Probably won't be attractive to cavers and wreck penetrators, but for the open-water guys who don't want to spend $50+ on a small LED flashlight, this looks great. I'll definitely be trying it out.

 

[Jake25]

What's stopping the mineral oil from leaking OUT of the flashlight

 

[CMAN]

What's stopping the mineral oil from leaking OUT of the flashlight

The o-rings. One small problem I see is you will have to refill the oil every battery change which could be problematic while on a boat or on a dive vacation, still I think I will give it a try.

 

[BoneCrusher]

Thats cool. I knew they did that with some dive computers. Just hadn't thought of doing it with a cheap LED flashlight. Im going to try it as well! Thanks for posting it!

 

[elmer fudd]

The one thing I'd be wondering about is the switch. Almost all of the cheap LED lights I have seen have button style switches with rubber covers. Since mineral oil is not compressible, every time you push the switch in you are either going to push a little bit of mineral oil out or you are going to cause something like the lens to bulge. If mineral oil leaks out when you turn the light on, then one of two things is going to happen, either water will flow in to fill the void or the switch will remain pushed in. Neither one of these is really acceptable. If salt water gets inside your light will soon be toast and a dive light really should be something you can turn off.

 

[Bob01]

Any updates on the implementations of this DIY project? I'm considering picking up a "nicer" cree light off dealextreme to try this out on ;-)

 

[jeasy]

I'd be curious to actually see what brands/models of flashlights this has worked with and too what depths. I went to the home depot website but I couldn't find any LED flashlights that were 3 for $10 like the ones used in the video.

 

[elmer fudd]

Harbor Freight usually has them. They're generally 2/$10, but they discount them to 2/$4 regularly. I bought a bunch last winter and used them to illuminate hanging targets at night on an airgun range that I had set up. They worked pretty well for that, but I'd want something much brighter for a serious dive light.

 

[ac777]

My home depot had them for $2 a peice. The only thing I see is the lense needs an o'ring to make it work right.With out it may leak????

 

[sleepr]

I just made one and tested it in 45 feet. The light I found was at Home Depot, a 19 led light with 3 AAA batteries and an aluminum case. One issue I had was the lens did not have an o ring so I ran a bead of silicon around the outer perimeter of the lens. Getting the air bubbles out of the led board was done with the drill like shown in the video and then by using a small syringe to push the mineral oil into the lens displacing the air. This was just to see how it would work and it did like a charm. Light was $9.99 and mineral oil was about $10. I probably could have got away with less oil but did not have a shallow long enough container for the light. Did seem to weep a little oil so I stowed it in a ziploc bag for transport.

PS I will change batteries at at home before any trip so I don't have to find mineral oil.